research article synthesis, structural characterization...

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Research Article Synthesis, Structural Characterization, and Biological Activity Studies of Ni(II) and Zn(II) Complexes Palakuri Kavitha and K. Laxma Reddy Department of Chemistry, National Institute of Technology, Warangal 506 004, India Correspondence should be addressed to K. Laxma Reddy; [email protected] Received 28 October 2013; Accepted 26 March 2014; Published 28 April 2014 Academic Editor: Imre Sovago Copyright © 2014 P. Kavitha and K. L. Reddy. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Ni(II) and Zn(II) complexes were synthesized from tridentate 3-formyl chromone Schiff bases such as 3-((2-hydroxyphenyli- mino)methyl)-4H-chromen-4-one (HL 1 ), 2-((4-oxo-4H-chromen-3-yl)methylneamino)benzoic acid (HL 2 ), 3-((3-hydroxypyri- din-2-ylimino)methyl)-4H-chromen-4-one (HL 3 ), and 3-((2-mercaptophenylimino)methyl)-4H-chromen-4-one (HL 4 ). All the complexes were characterized in the light of elemental analysis, molar conductance, FTIR, UV-VIS, magnetic, thermal, powder XRD, and SEM studies. e conductance and spectroscopic data suggested that, the ligands act as neutral and monobasic tridentate ligands and form octahedral complexes with general formula [M(L 1−4 )2]nH 2 O (M = Ni(II) and Zn(II)). Metal complexes exhibited pronounced activity against tested bacteria and fungi strains compared to the ligands. In addition metal complexes displayed good antioxidant and moderate nematicidal activities. e cytotoxicity of ligands and their metal complexes have been evaluated by MTT assay. e DNA cleavage activity of the metal complexes was performed using agarose gel electrophoresis in the presence and absence of oxidant H 2 O 2 . All metal complexes showed significant nuclease activity in the presence of H 2 O 2 . 1. Introduction Metal complexes of O, S, and N containing Schiff bases have been the subject of current and growing interest because it has wide range of pharmacological activities [1]. In particular Schiff bases with 2-amino thiophenol, 2-amino phenol, 2- amino benzoic acid, and 2-amino 3-hydroxy pyridine exhibit various biological activities such as antimicrobial activity, protein tyrosine phosphatases inhibition, and nuclease activ- ity [2, 3]. Several aromatic amine Schiff bases have been investigated but few works deal with chromone skeleton derivatives. Chromones are a group of naturally occurring compounds that are ubiquitous in nature especially in plants. Molecules containing the chromone skeleton have extensive biological applications including antimycobacterial, anti- fungal, anticancer, antioxidant, antihypertensive, and anti- inflammatory applications and tyrosinase and protein kinase C inhibitors [413]. DNA plays an important role in the life process since it contains all the genetic information for the cellular func- tion. However, DNA is the primary intracellular target of anticancer drugs, damaged under various conditions such as interactions with some small molecules, which cause DNA damage in cancer cells blocking the division of cancer cells and resulting in cell death. Metal complexes such as cobalt, nickel, copper, and zinc with Schiff base ligands have shown excellent binding and cleavage activities [1416]. ere is substantial literature supporting the DNA binding studies of chromone Schiff bases and their metal complexes [1719]. Compounds showing the properties of effective binding as well as cleaving double stranded DNA under physiological conditions are of great importance since these could be used as diagnostic agents in medicinal and genomic research. Fluorescent transition metal centres are particularly attractive moieties because they oſten possess distinctive electrochemical or photophysical properties, thus enhancing the functionality of the binding agent [20]. In previous papers we presented synthesis, detailed characterization, and biological activity studies of 3-formyl chromone Schiff bases such as 3-((2-hydroxy phenylimino)- methyl)-4H-chromen-4-one (HL 1 ), 2-((4-oxo-4H-chromen- 3-yl)methylneamino)benzoic acid (HL 2 ), 3-((3-hydroxypy- Hindawi Publishing Corporation Bioinorganic Chemistry and Applications Volume 2014, Article ID 568741, 13 pages http://dx.doi.org/10.1155/2014/568741

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Page 1: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Research ArticleSynthesis Structural Characterization and Biological ActivityStudies of Ni(II) and Zn(II) Complexes

Palakuri Kavitha and K Laxma Reddy

Department of Chemistry National Institute of Technology Warangal 506 004 India

Correspondence should be addressed to K Laxma Reddy laxmareddychem12gmailcom

Received 28 October 2013 Accepted 26 March 2014 Published 28 April 2014

Academic Editor Imre Sovago

Copyright copy 2014 P Kavitha and K L Reddy This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Ni(II) and Zn(II) complexes were synthesized from tridentate 3-formyl chromone Schiff bases such as 3-((2-hydroxyphenyli-mino)methyl)-4H-chromen-4-one (HL

1) 2-((4-oxo-4H-chromen-3-yl)methylneamino)benzoic acid (HL

2) 3-((3-hydroxypyri-

din-2-ylimino)methyl)-4H-chromen-4-one (HL3) and 3-((2-mercaptophenylimino)methyl)-4H-chromen-4-one (HL

4) All the

complexes were characterized in the light of elemental analysis molar conductance FTIR UV-VIS magnetic thermal powderXRD and SEM studiesThe conductance and spectroscopic data suggested that the ligands act as neutral andmonobasic tridentateligands and form octahedral complexes with general formula [M(L

1minus4)2]sdotnH

2O (M=Ni(II) and Zn(II)) Metal complexes exhibited

pronounced activity against tested bacteria and fungi strains compared to the ligands In addition metal complexes displayed goodantioxidant and moderate nematicidal activities The cytotoxicity of ligands and their metal complexes have been evaluated byMTT assayThe DNA cleavage activity of the metal complexes was performed using agarose gel electrophoresis in the presence andabsence of oxidant H

2O2 All metal complexes showed significant nuclease activity in the presence of H

2O2

1 Introduction

Metal complexes of O S and N containing Schiff bases havebeen the subject of current and growing interest because ithas wide range of pharmacological activities [1] In particularSchiff bases with 2-amino thiophenol 2-amino phenol 2-amino benzoic acid and 2-amino 3-hydroxy pyridine exhibitvarious biological activities such as antimicrobial activityprotein tyrosine phosphatases inhibition and nuclease activ-ity [2 3] Several aromatic amine Schiff bases have beeninvestigated but few works deal with chromone skeletonderivatives Chromones are a group of naturally occurringcompounds that are ubiquitous in nature especially in plantsMolecules containing the chromone skeleton have extensivebiological applications including antimycobacterial anti-fungal anticancer antioxidant antihypertensive and anti-inflammatory applications and tyrosinase and protein kinaseC inhibitors [4ndash13]

DNA plays an important role in the life process sinceit contains all the genetic information for the cellular func-tion However DNA is the primary intracellular target of

anticancer drugs damaged under various conditions such asinteractions with some small molecules which cause DNAdamage in cancer cells blocking the division of cancer cellsand resulting in cell death Metal complexes such as cobaltnickel copper and zinc with Schiff base ligands have shownexcellent binding and cleavage activities [14ndash16] There issubstantial literature supporting the DNA binding studies ofchromone Schiff bases and their metal complexes [17ndash19]Compounds showing the properties of effective binding aswell as cleaving double stranded DNA under physiologicalconditions are of great importance since these could be usedas diagnostic agents in medicinal and genomic research

Fluorescent transition metal centres are particularlyattractive moieties because they often possess distinctiveelectrochemical or photophysical properties thus enhancingthe functionality of the binding agent [20]

In previous papers we presented synthesis detailedcharacterization and biological activity studies of 3-formylchromone Schiff bases such as 3-((2-hydroxy phenylimino)-methyl)-4H-chromen-4-one (HL

1) 2-((4-oxo-4H-chromen-

3-yl)methylneamino)benzoic acid (HL2) 3-((3-hydroxypy-

Hindawi Publishing CorporationBioinorganic Chemistry and ApplicationsVolume 2014 Article ID 568741 13 pageshttpdxdoiorg1011552014568741

2 Bioinorganic Chemistry and Applications

ridin-2-ylimino)methyl)-4H-chromen-4-one (HL3) 3-((2-

mercapto phenylimino)methyl)-4H-chromen-4-one (HL4)

and their Cu(II) Co(II) and Pd(II) complexes [21ndash23] Thepresent paper deals with the synthesis characterization ofNi(II) and Zn(II) complexes of 3-formyl chromone Schiffbases (HL

1 HL2 HL3 and HL

4) and various biologi-

cal activity studies that is antimicrobial antioxidant andnematicidal activities and cytotoxicity and DNA cleavage

2 Experimental

21 Materials and Physical Measurements All the chemicalsused were of analytical grade and procured from Spec-trochem Pvt Ltd Mumbai India 3-Formyl chromone wassynthesized according to the literature [24]

The elemental analysis of carbon hydrogen nitrogen andsulphur contents was performed using Perkin Elmer CHNSanalyser Molar conductance of the complexes was measuredusing a Digisun conductivity meter in DMF The electronicabsorption spectra of the complexes were recorded on JASCOV-670 Spectrophotometer in the wavelength region of 250ndash1400 nm in the solid stateThe FTIR spectra of the complexeswere recorded on Tensor 2 FTIR spectrophotometer in theregion of 4000ndash400 cmminus1 using KBr disc The magnetic sus-ceptibilities of Ni(II) complexes were measured with a Sher-wood scientific balance Diamagnetic corrections were calcu-lated from Pascalrsquos constants The magnetic moment valueswere calculated using the relation 120583eff = 283 (120594119898119879)

12 BMThermal studies of the complexeswere carried out on aPerkinElmer diamond TGA instrument at a heating rate of 10∘C andnitrogen flow rate of 20mLmin The fluorescence spectra ofthe complexes were recorded on Fluorolog FL3-11 spectroflu-orometerThe X-ray patterns of the complexes were recordedonXpert-Pro X-ray diffractometer with CuK120572 radiation (120582 =15406 A) The diffraction data are integrated by using theNakamuta program Scanning electron micrograph (SEM)of the complexes was obtained in a Hitachi S-520 electronmicroscope at an accelerated voltage of 15 kV

22 Synthesis of Ligands All the Schiff base ligands HL1

HL2 HL3 and HL

4(Figure 1) were prepared according to the

literature methods [21 25 26]

23 Synthesis of Metal Complexes The ligands (2mM)and metal acetates (Ni(CH

3COOH)

2sdot4H2O and Zn(CH

3

COOH)2sdot2H2O) (1mM) were dissolved in methanol The

mixtures were stirred at room temperature for 2-3 h variouscolour precipitates were separated from the solution bysuction filtration purified by washing several times withmethanol and dried for 12 h in vacuum

24 Antimicrobial Activity In vitro antimicrobial activity ofthe metal complexes towards the bacteria Proteus vulgarisKlebsiella pnuemoniae Staphylococcus aureus and Bacillussubtili and fungi Candida albicans was carried out using discdiffusion method The antibiotics kanamycin and clotrima-zole are the standards for antibacterial and antifungal activitystudies Standard inoculum 1-2 times 107 cfumL 05Mc Farland

O

O HC N

OH

3-(-(2-Hydroxyphenylimino)methyl)-4H-chromen-4-one(HL1)

(a)

O

O HC N

C OHO

2-((4-Oxo-4H-chromen-3-yl)methyleneamino)benzoic acid(HL2)

(b)

O

O HC N

N

OH

3-((3-Hydroxypyridin-2-ylimino)methyl)-4H-chromen-4-one(HL3)

(c)

O

O HC N

SH

3-(-(2-Mercaptophenylimino)methyl)-4H-chromen-4-one(HL4)

(d)

Figure 1 Structures of Schiff base ligands

standards [27] was introduced onto the surface of sterilenutrient agar plate and evenly spread by using a sterile glassspreader Sterile antibiotic discs (6mm in diameter preparedusing Whatmann number 1 paper) were placed over thenutrient agar medium Each disc was spread by 100 120583g of thecompounds (initially dissolved in DMSO) The plates wereincubated with bacterial cultures for 24 h at 37∘C and fungalcultures at 25∘C for 48 h The activity of the compounds wasdetermined by measuring the diameter of inhibition zonein ldquomillimetresrdquo and compared with standard antibioticsDMSO (which has no activity) and standard antibioticswere used as negative and positive controls for antimicrobialactivity studies The activity results are calculated as a meanof triplicates

Minimum inhibitory concentrations (MIC) of the com-plexes which showed antimicrobial activity were determinedusing the literature method [28] All the compounds thatwere diluted within the range of 100ndash10 120583gmL were mixedin nutrient broth and 01mL of active inoculums was addedto each tube The tubes were incubated aerobically at 37∘Cfor bacteria and 25∘C for fungi up to 24 h The lowestconcentration of the compound that completely inhibited

Bioinorganic Chemistry and Applications 3

bacterial growth (no turbidity) in comparison to control wasregarded as MIC

25 Nematicidal Activity Root knot nematodeMeloidogyneincognita is major plant parasitic nematodes affecting quan-tity and quality of the crop production in many annual andperennial crops Meloidogyne nematode can develop gallsand lesions in the roots thereby causing stunted growth ofthe plants Some of the chemicals can be used to controlnematodes [29]

Nematicidal activity of the complexes was carried outon Meloidogyne incognita Fresh egg masses of Meloidogyneincognita are collected from stock culture maintained ontomato (Lycopersicon esculentum) root tissues and kept inwater for egg hatchingThe eggs suspensions were poured ona cotton wool filter paper and incubated at 30∘C to obtainfreshly hatched juveniles (J2) Juveniles collected within48 h were used for screening nematicidal activity of thecompounds

The compounds were initially dissolved in dimethyl sul-foxide (DMSO) and then in distilled water to make dilutionsof 250 150 and 50 120583gmL Experiments were performedunder laboratory conditions at 30∘C About 100 freshlyhatched second stage juveniles were suspended in 5mL ofeach diluted compound and incubated Distilled water withnematode larvae was taken as control The dead nematodeswere observed under an inverted binocularmicroscope Afteran incubation of 24 and 48 h percentage of mortality wascalculated Nematodes were considered dead if they did notmove when probed with a fine needle [30]

26 DPPH Radical Scavenging Activity The free radicalscavenging activities of themetal complexes were determinedby using DPPH free radical scavenging method according tothe literature [31] DPPH is a stable free radical containing anodd electron in its structure and usually utilized for detectionof the radical scavenging activity in chemical analysis Inthe spectrophotometric assay the ability to scavenge thestable free radical DPPH is measured by decrease in theabsorbance at 517 nm Each compound was dissolved inmethanol (10mg10mL) and it was used as stock solutionFrom the stock solutions 1mL of each compound solutionwith different concentrations (025120583gndash100 120583g) was addedto the 3mL of methanolic DPPH (0004) solution After30min the absorbance of the test compounds was taken at517 nm using UV-VIS spectrophotometer BHT was used asstandard DPPH solution was used as control without the testcompounds andmethanol was used as blankThe percentageof scavenging activity of DPPH free radical was measured byusing the following formula

Scavenging activity () = [(119860

119900minus 119860

119894)

119860

119900

] times 100 (1)

where 119860119900is the absorbance of the control and 119860

119894is the

absorbance of the sample

27 Cytotoxic Activity The human breast carcinoma cellline (MCF-7) human colon carcinoma cell line (COLO

205) and murine microphage cell line (Raw 2647) wereobtained from the National Centre for Cell Science (NCCS)Pune and grown in Dulbeccorsquos Modified Eagles Medium(DMEM) containing 10 fetal bovine serum (FBS) ampho-tericin (3 120583gmL) gentamycin (400 120583gmL) streptomycin(250 120583gmL) and penicillin (250 unitsmL) in a carbon diox-ide incubator at 5CO

2 About 700 cellswell were seeded in

96-well plate using culture medium the viability was testedusing trypan blue dye with help of haemocytometer and 95of viability was confirmed After 24 h the new medium withcompounds in the concentration of 100 10 and 1120583gmL wereadded at respective wells and kept in incubation for 48 hAfter incubation MTT assay was performed

271 MTT Assay After 48 h of the drug treatment themedium was changed again for all groups and 10120583L of MTT(5mgmL stock solution) was added and the plates wereincubated for an additional 4 h The medium was discardedand the formazan blue which was formed in the cells wasdissolved with 50120583L of DMSO The optical density wasmeasured on microplate spectrophotometer at a wavelengthof 570 nmThe percentage of cell inhibition was calculated byusing the following formula [32]

Growth inhibition = 100 minus (119860

119894

119860

119900

) times 100 (2)

where 119860119894is the absorbance of the sample and 119860

119900is the

absorbance of the control IC50values were determined using

Graph Pad Prism software

28 DNA Cleavage Activity The DNA cleavage activity ofmetal complexes was monitored by agarose gel electrophore-sis pUC19 plasmid was cultured isolated and used as DNAfor the experiment Test samples (1mgmL) were preparedin DMF 25 120583g of the test samples was added to the isolatedplasmid and incubated for 2 h at 37∘C After incubation30 120583L of plasmid DNA sample mixed with bromophenol bluedye (1 1) was loaded into the electrophoresis chamber wellsalong with the control DNA 5M FeSO

4(treated with DNA)

and standard DNA marker containing TAE buffer (484 gTris base pH 80 05M EDTA1 L) Finally it was loadedon to an agarose gel and electrophoresed at 50V constantvoltage up to 30min After the run gel was removed andstained with 1001 120583gmL ethidium bromide and image wastaken in Versadoc (Biorad) imaging system The results werecompared with standard DNA marker The same procedurewas followed in the presence of H

2O2also

3 Results and Discussion

All the Ni(II) complexes were colored stable and nonhygro-scopic in nature The complexes are insoluble in commonorganic solvents but soluble inDMF andDMSOThe elemen-tal analysis showed that the complexes have 1 2 stoichiome-try of the type [M(L

1ndash4)2]sdot119899H2O where L stands for singlydeprotonated ligands Molar conductance of the complexeswas measured in DMF The conductance values which are

4 Bioinorganic Chemistry and Applications

presented in the Table 1 indicate the nonelectrolytic natureof the complexes [33]

31 Determination of the Metal Content of the ComplexesKnown amount (0150 g) of complexes was decomposedwith concentrated nitric acid This process was repeatedtill the organic part of the complexes got completely lostThe excess nitric acid was expelled by evaporation withconcentrated sulphuric acid The Ni(II) and Zn(II) contentsof the complexes were determined as per the procedureavailable in the literature [34]

32 FTIR Spectra The FTIR spectra of the complexes arecompared with those of the ligands in order to determinethe coordination sites that may involve in chelation Theposition andor the intensities of bands are expected to bechanged while the coordination The most important IRbands of the metal complexes with probable assignments aregiven in Table 2 The Schiff base ligands showing a bandaround 1650ndash1620 cmminus1 is assigned to the (C=O) group ofthe chromone system Upon complexation the ](C=O) groupis shifted to 20ndash35 cmminus1 lower wavenumber region [35] Theligands show the most characteristic ](C=N) bands in theregion 1605ndash1563 cmminus1 In the spectra of their correspond-ing metal complexes this band appears at 25ndash45 cmminus1 tolower wavenumber region indicating the coordination of theazomethine nitrogen atom to the metal ion [36] A broadband appeared in HL

1and HL

3at 3241 and 3246 cmminus1

respectively and is attributed to the ](OndashH) group Theabsence of the band in the spectra of their correspondingmetal complexes is due to the involvement of oxygen atomof (OH) group coordination to the metal ion In HL

2ligand

a strong band appeared at 1365 cmminus1 and is due to the ](CndashO)of carboxylic group In its metal complexes it is shifted to 18ndash47 cmminus1 lower wavenumber region [37] Since SH stretchingfrequency band is very weak the peak corresponding toSH is not clearly observed in the case of HL

4ligand [38]

Presence of band around 3400 cmminus1 in all the complexes is theindication of water molecules present in the complexes Thepresence of oxygen and nitrogen in the coordination sphereis further confirmed by the presence of ](MndashN) and ](MndashO)bands at 400ndash600 cmminus1 regionThe FTIR results show that allSchiff base ligands act as tridentate chelating ligands

33 Electronic Spectra andMagneticMoments The electronicabsorption spectra of the Schiff base metal complexes insolid state were recorded at room temperature and theband positions of the absorption maxima band assignmentsligand field parameters and magnetic moment values arelisted in Table 3 The electronic spectra of [Ni(L

4)2]sdotH2O

and [Zn(L4)2]sdotH2O complexes are depicted in Figure 2

The electronic spectra of Ni(II) complexes displayed threeabsorption bands in the range 8000ndash9000 14000ndash16000 and20000ndash24000 cmminus1 Thus these bands may be assigned tothe three spin allowed transitions 3A

2g (F)rarr3T2g (F) (]1)

3A2g (F) rarr 3T

1g (F) (]2) and 3A

2g (F) rarr 3T1g (P) (]

3)

respectively characteristic of octahedral geometryThe values

of transition ratio ]2]1and 120573 lie in the range of 170ndash180

and 089ndash095 respectively providing further evidence foroctahedral geometry of Ni(II) complexes [39] The B valuesfor the complexes are lower than the free ion value therebyindicating orbital overlap anddelocalisation of d-orbitalsThe120573-values obtained are less than unity suggesting the covalentcharacter of the metal-ligand bonds All Ni(II) complexes areparamagnetic and the magnetic movement values at roomtemperature are in the range of 291ndash325 BM which is wellagreed with the reported octahedral Ni(II) complexes [40]All Zn(II) complexes showed two bands around 25000 and30000 cmminus1 and are attributed to the 119899 rarr 120587lowast and 120587 rarr120587

lowast transitions respectively Zn(II) complexes that are in d10configuration are diamagnetic and do not show any d-dtransitions

34 Thermal Analysis The thermogravimetric analysis(TGA) of the metal complexes was carried out within thetemperature range from room temperature to 1000∘C TheTG-DTA graphs of [Ni(L

4)2] and [Zn(L

4)2]sdotH2O complexes

are given in Figure 3 The TGA data and their assignments ofall the metal complexes are listed in Table 4 Metal complexesdecompose gradually with formation of respective metaloxides The TG graphs of [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Zn(L1)2]sdotH2O and [Zn(L

4)2]sdotH2O complexes decompose

in two to three steps The first step corresponds to the lossof lattice water molecule in the temperature range between30 and 140∘C with a weight loss of 2-3 In the second andthird steps the total loss of ligand molecules was observedin the temperature range between 160 and 850∘C leavingbehindmetal oxide as residueThe thermal decomposition ofremaining metal complexes ([Ni(L

1)2] [Ni(L

4)2] [Zn(L

2)2]

and [Zn(L3)2]) occurs in two to three steps Upon starting

heating these metal complexes losses of the organic moietiesof Schiff base ligands were observed in two to three successivesteps within the temperature range of 150ndash850∘C In all thecomplexes the final mass loss is due to the formation of metaloxides as residue

On the basis of all spectral data (elemental analysisFTIR electronic spectra and thermal analysis) the suggestedstructures of the complexes are shown in Figure 4

35 Powder XRD and SEM Studies Single crystals of thecomplexes could not be obtained because of their insolubilityin most organic solvents hence the powder diffraction datawere obtained for structural characterization The powderXRD patterns of all metal complexes were recorded in therange 2120579 = 10ndash50∘ The powder XRD pattern of [Ni(L

1)2]

and [Zn(L1)2]sdotH2O are presented in Figure 5 Observed and

calculated powder XRD data of [Ni(L1)2] and [Zn(L

1)2]sdotH2O

are given in Tables 5(a) and 5(b) Unit cell parameterswere found by using trial and error methods All complexesare triclinic with different unit cell parameters All metalcomplexes display sharp crystalline peaks except [Zn(L

2)2]

and [Zn(L4)2]sdotH2O these two complexes do not exhibit well-

defined crystalline peaks due to their amorphous natureThe unit cell parameters of metal complexes are as follows[Ni(L1)2] 119886 = 880 A 119887 = 852 A 119888 = 750 A 120572 = 9993∘

Bioinorganic Chemistry and Applications 5

Table 1 Elemental analysis and physical properties of metal complexes

Molecular formulaColour( yield)

found(cald) Molar conductivity

(Ohmminus1 cm2 molminus1)C H N S M(NiZn)

[Ni(L1)2] Brick red 6449 321 423 991 10[Ni(C16H10O3N)2] (71) (6545) (340) (477) (1000)[Ni(L2)2]sdotH2O Light green 6159 302 421 879 12[Ni(C17H10O4N)2]sdotH2O (62) (6175) (332) (424) (888)[Ni(L3)2]sdotH2O Brick red 6107 323 923 943 15[Ni(C15H9O3N2)2]sdotH2O (85) (6115) (339) (951) (997)[Ni(L4)2] Black 6221 309 461 930 921 14[Ni(C16H10O2NS)2] (82) (6206) (323) (452) (1034) (949)[Zn(L1)2]sdotH2O Orange 6291 352 462 1058 15[Zn(C16H10O3N)2]sdotH2O (88) (6280) (360) (458) (1070)[Zn(L2)2] Yellow 6279 315 425 995 11[Zn(C17H10O4N)2] (61) (6283) (308) (431) (1007)[Zn(L3)2] Brick red 6021 325 935 1051 18[Zn(C15H9O3N2)2] (87) (6046) (302) (940) (1098)[Zn(L4)2]sdotH2O Yellow 6022 335 421 1001 1031 20[Zn(C16H10O2NS)2]sdotH2O (73) (5968) (341) (435) (993) (1046)

Table 2 IR spectral data of ligands and their metal complexes (cmminus1)

Compound ](OH) ](C=O) (120574 pyrone) ](C=N) ](CO) (carboxylate) ](CndashS) ](MndashN) ](MndashO)HL1 3241 1643 1605HL2 1651 1605 1365HL3 3246 1647 1591HL4 1622 1597 790[Ni(L1)2] 1619 1563 467 586[Ni(L2)2]sdotH2O 1618 1570 1318 419 514[Ni(L3)2]sdotH2O 1615 1563 480 500[Ni(L4)2] 1598 1564 743 443 524[Zn(L1)2]sdotH2O 1614 1574 460 599[Zn(L2)2] 1615 1563 1347 480 500[Zn(L3)2] 1615 1563 488 521[Zn(L4)2]sdotH2O 1609 1581 751 441 505

120573 = 11671

∘ 120574 = 9001∘ and 119881 = 562 (A)3 [Ni(L2)2]sdotH2O

119886 = 824 A 119887 = 924 A 119888 = 732 A 120572 = 10412∘ 120573 = 12444∘120574 = 9804

∘ and 119881 = 557 (A)3 [Ni(L3)2]sdotH2O 119886 = 940 A

119887 = 920 A 119888 = 846 A 120572 = 9745∘ 120573 = 10738∘ 120574 = 9145∘and 119881 = 731 (A)3 [Ni(L

4)2] 119886 = 773 A 119887 = 824 A

119888 = 849 A 120572 = 9830∘ 120573 = 10476∘ 120574 = 9055∘ and119881 = 540 (A)3 [Zn(L

1)2]sdotH2O 119886 = 960 A 119887 = 994 A

119888 = 889 A 120572 = 10234∘ 120573 = 10969∘ 120574 = 9394∘ and119881 = 848 (A)3 [Zn(L

3)2] 119886 = 876 A 119887 = 904 A 119888 = 861 A

120572 = 10578

∘ 120573 = 10302∘ 120574 = 9021∘ and 119881 = 682 (A)3The average crystallite sizes (119863) of the metal complexes arecalculated from the Scherrer formula [41]

119863 =

09120582

120573 cos 120579 (3)

where 120582 is the X-ray wavelength 120573 is the full width at halfmaximum of prominent intensity peak and 120579 is the diffrac-tion angle The [Ni(L

1)2] [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Ni(L4)2] [Zn(L

1)2]sdotH2O and [Zn(L

3)2] complexes have an

average crystallite size of 70 17 16 27 42 and 53 nm respec-tively suggesting that the complexes are in nanocrystallinephase

The SEM (Scanning Electron Microscope) is used toevaluate the morphology and particle size of the compoundsThe SEM photographs of [Ni(L

3)2]sdotH2O and [Ni(L

4)2] are

shown in Figure 6 The SEM micrographs show the agglom-erate particles of the complexes In case of [Ni(L

3)2]sdotH2O

and [Ni(L4)2] complexes some agglomerates appear to have

tiny needles while the other agglomerates appear to be ofspherical plates like morphologies

6 Bioinorganic Chemistry and Applications

Table 3 Electronic magnetic and ligand field parameters of Ni(II) complexes

Compound Absorption maxima(cmminus1) Tentative assignments Magnetic moment

(BM)]2]1

10Dq(cmminus1)

B(cmminus1)

120573

LFSE(kJsdotmolminus1)

[Ni(L1)2]85321520024900

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

312 178 8532 966 092 12250

[Ni( L2)2]sdotH2O87871600024390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

318 182 8787 935 089 12619

[Ni(L3)2]sdotH2O8313147052083324390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

325 176 8313 943 090 11940

[Ni(L4)2]86281631324570

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

291 189 8628 999 095 12392

Table 4 Thermal analysis results of metal complexes

Compound Temperature (∘C) Found (cald) Assignment

[Ni(L1)2][Ni(C16H10O3N)2]

180ndash420 1938 (1836) C6H4ON

421ndash718 6855 (6902) C26H16O5N

gt718 1207 (1262) NiO

[Ni(L2)2]sdotH2O[Ni(C17H10O4N)2]sdotH2O

30ndash90 283 (272) H2O335ndash478 6071 (6205) C24H14O5N2

479ndash849 2393 (2361) C10H6O2

gt849 1253 (1162) NiO

[Ni(L3)2]sdotH2O[Ni(C15H9O3N2)2]sdotH2O

30ndash65 309 (296) H2O180ndash879 8340 (8473) C30H18O5N4

gt880 1351 (1231) NiO

[Ni(L4)2][Ni(C16H10O2NS)2]

171ndash410 4591 (4525) C16H10O2NS411ndash670 4214 (4267) C16H10ONSgt670 1195 (1207) NiO

[Zn(L1)2]sdotH2O[Zn(C16H10O3N)2]sdotH2O

30ndash135 245 (295) H2O194ndash422 2495 (2592) C10H6O2

423ndash790 5948 (5809) C22H14O3N2

gt791 1312 (1304) ZnO

[Zn(L2)2][Zn(C17H10O4N)2]

195ndash265 1555 (1601) C7H4O266ndash661 6976 (7146) C27H16O4N2

gt662 1469 (1253) ZnO

[Zn(L3)2][Zn(C15H9O3N2)2]

157ndash192 1091 (1293) C5H3N193ndash485 2865 (2922) C10H6O2N486ndash835 4603 (4418) C15H9O3N2

gt836 1441 (1367) ZnO

[Zn(L4)2]sdotH2O[Zn(C16H10O2NS)2]sdotH2O

30ndash124 241 (279) H2O165ndash348 2741 (2673) C10H6O2N389ndash632 5698 (5784) C22H14ONS2gt632 1320 (1264) ZnO

Bioinorganic Chemistry and Applications 7

Table 5 Observed and calculated powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L1)2]sdotH2O

(a)

S number 2120579

Δ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1057 1057 0 83627 83627 0 1 02 1129 1129 0 78314 78314 1 0 03 1344 1344 0 65805 65805 0 0 14 1479 1479 0 59847 59847 minus1 1 05 1575 1575 0 56205 56205 minus1 minus1 16 1779 1779 0 49805 49805 minus1 1 17 1885 1868 0164 47046 47455 0 1 18 2116 2122 minus006 41962 41845 1 0 19 2214 2206 0074 40121 40255 1 minus1 110 2405 2407 minus0013 36968 36948 minus1 0 211 2504 2499 0054 35533 35608 1 2 012 2633 2635 minus0017 3382 33799 minus1 2 113 281 2804 0061 31731 31799 minus1 1 214 3265 3265 0 27404 27405 2 2 015 3506 3507 minus0012 25575 25566 minus3 1 016 3892 3886 0054 23124 23155 minus2 3 117 4389 4395 minus0058 20612 20586 minus1 3 218 4513 4516 minus0033 20076 20062 minus2 minus3 3

(b)

S number 2120579 valuesΔ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1258 1258 0 70315 70315 1 1 02 1381 1381 0 64077 64077 minus1 0 13 1573 1573 0 56299 56299 1 0 14 1735 1735 0 51064 51064 minus1 1 15 2075 2077 minus0017 42777 42742 minus1 3 06 2409 2413 minus0031 36907 36859 minus1 minus3 27 2532 2531 0012 35141 35158 2 2 08 2793 2797 minus0038 31916 31873 minus1 minus4 29 3015 3016 minus0008 29620 29612 0 minus3 310 3192 3190 0021 28015 28033 2 minus5 211 3443 3445 minus0017 26028 26016 minus1 5 012 3605 3606 minus0008 24892 24886 minus1 0 313 4275 4283 minus0081 21137 21099 3 1 2

36 Fluorescence Spectra The fluorescence characteristics ofmetal complexes were studied at room temperature in solidstate In metal complexes metal to ligand coordination maylead to significant changes of the fluorescence properties ofthe ligand including increase or decrease of the intensityemission wavelength shift quenching of the fluorescence orappearance of new emissions [42] The fluorescence spectraof HL

1ligand and its metal (Ni(II) and Zn(II)) complexes

were depicted in Figure 7 The Ni(II) and Zn(II) complexesof HL

1were characterised by emission bands around (522

569) nm and (458 644) nm upon photo excitation at 453and 357 nm respectively The Ni(II) complex of HL

2exhibits

emission bands at 449 and 524 nm Zn(II) complex of HL2

does not show any emission spectra The Ni(II) and Zn(II)complexes of HL

3were characterised by an emission bands

at (504 570 and 668) and 419 nm respectively The Ni(II)and Zn(II) complexes of HL

4exhibit emission bands around

539 and 613 nm respectively From the results red shift andquenching of the metal ions was observed in the case ofligands and its metal complexes

37 Antimicrobial Activity Theminimum inhibitory concen-trations (MIC) of the complexes compared with the ligandsand standard drugs are listed in Table 6 The results indicatethat themetal complexes displayedmore antibacterial activitycompared to the parent ligands under similar experimental

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

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Page 2: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

2 Bioinorganic Chemistry and Applications

ridin-2-ylimino)methyl)-4H-chromen-4-one (HL3) 3-((2-

mercapto phenylimino)methyl)-4H-chromen-4-one (HL4)

and their Cu(II) Co(II) and Pd(II) complexes [21ndash23] Thepresent paper deals with the synthesis characterization ofNi(II) and Zn(II) complexes of 3-formyl chromone Schiffbases (HL

1 HL2 HL3 and HL

4) and various biologi-

cal activity studies that is antimicrobial antioxidant andnematicidal activities and cytotoxicity and DNA cleavage

2 Experimental

21 Materials and Physical Measurements All the chemicalsused were of analytical grade and procured from Spec-trochem Pvt Ltd Mumbai India 3-Formyl chromone wassynthesized according to the literature [24]

The elemental analysis of carbon hydrogen nitrogen andsulphur contents was performed using Perkin Elmer CHNSanalyser Molar conductance of the complexes was measuredusing a Digisun conductivity meter in DMF The electronicabsorption spectra of the complexes were recorded on JASCOV-670 Spectrophotometer in the wavelength region of 250ndash1400 nm in the solid stateThe FTIR spectra of the complexeswere recorded on Tensor 2 FTIR spectrophotometer in theregion of 4000ndash400 cmminus1 using KBr disc The magnetic sus-ceptibilities of Ni(II) complexes were measured with a Sher-wood scientific balance Diamagnetic corrections were calcu-lated from Pascalrsquos constants The magnetic moment valueswere calculated using the relation 120583eff = 283 (120594119898119879)

12 BMThermal studies of the complexeswere carried out on aPerkinElmer diamond TGA instrument at a heating rate of 10∘C andnitrogen flow rate of 20mLmin The fluorescence spectra ofthe complexes were recorded on Fluorolog FL3-11 spectroflu-orometerThe X-ray patterns of the complexes were recordedonXpert-Pro X-ray diffractometer with CuK120572 radiation (120582 =15406 A) The diffraction data are integrated by using theNakamuta program Scanning electron micrograph (SEM)of the complexes was obtained in a Hitachi S-520 electronmicroscope at an accelerated voltage of 15 kV

22 Synthesis of Ligands All the Schiff base ligands HL1

HL2 HL3 and HL

4(Figure 1) were prepared according to the

literature methods [21 25 26]

23 Synthesis of Metal Complexes The ligands (2mM)and metal acetates (Ni(CH

3COOH)

2sdot4H2O and Zn(CH

3

COOH)2sdot2H2O) (1mM) were dissolved in methanol The

mixtures were stirred at room temperature for 2-3 h variouscolour precipitates were separated from the solution bysuction filtration purified by washing several times withmethanol and dried for 12 h in vacuum

24 Antimicrobial Activity In vitro antimicrobial activity ofthe metal complexes towards the bacteria Proteus vulgarisKlebsiella pnuemoniae Staphylococcus aureus and Bacillussubtili and fungi Candida albicans was carried out using discdiffusion method The antibiotics kanamycin and clotrima-zole are the standards for antibacterial and antifungal activitystudies Standard inoculum 1-2 times 107 cfumL 05Mc Farland

O

O HC N

OH

3-(-(2-Hydroxyphenylimino)methyl)-4H-chromen-4-one(HL1)

(a)

O

O HC N

C OHO

2-((4-Oxo-4H-chromen-3-yl)methyleneamino)benzoic acid(HL2)

(b)

O

O HC N

N

OH

3-((3-Hydroxypyridin-2-ylimino)methyl)-4H-chromen-4-one(HL3)

(c)

O

O HC N

SH

3-(-(2-Mercaptophenylimino)methyl)-4H-chromen-4-one(HL4)

(d)

Figure 1 Structures of Schiff base ligands

standards [27] was introduced onto the surface of sterilenutrient agar plate and evenly spread by using a sterile glassspreader Sterile antibiotic discs (6mm in diameter preparedusing Whatmann number 1 paper) were placed over thenutrient agar medium Each disc was spread by 100 120583g of thecompounds (initially dissolved in DMSO) The plates wereincubated with bacterial cultures for 24 h at 37∘C and fungalcultures at 25∘C for 48 h The activity of the compounds wasdetermined by measuring the diameter of inhibition zonein ldquomillimetresrdquo and compared with standard antibioticsDMSO (which has no activity) and standard antibioticswere used as negative and positive controls for antimicrobialactivity studies The activity results are calculated as a meanof triplicates

Minimum inhibitory concentrations (MIC) of the com-plexes which showed antimicrobial activity were determinedusing the literature method [28] All the compounds thatwere diluted within the range of 100ndash10 120583gmL were mixedin nutrient broth and 01mL of active inoculums was addedto each tube The tubes were incubated aerobically at 37∘Cfor bacteria and 25∘C for fungi up to 24 h The lowestconcentration of the compound that completely inhibited

Bioinorganic Chemistry and Applications 3

bacterial growth (no turbidity) in comparison to control wasregarded as MIC

25 Nematicidal Activity Root knot nematodeMeloidogyneincognita is major plant parasitic nematodes affecting quan-tity and quality of the crop production in many annual andperennial crops Meloidogyne nematode can develop gallsand lesions in the roots thereby causing stunted growth ofthe plants Some of the chemicals can be used to controlnematodes [29]

Nematicidal activity of the complexes was carried outon Meloidogyne incognita Fresh egg masses of Meloidogyneincognita are collected from stock culture maintained ontomato (Lycopersicon esculentum) root tissues and kept inwater for egg hatchingThe eggs suspensions were poured ona cotton wool filter paper and incubated at 30∘C to obtainfreshly hatched juveniles (J2) Juveniles collected within48 h were used for screening nematicidal activity of thecompounds

The compounds were initially dissolved in dimethyl sul-foxide (DMSO) and then in distilled water to make dilutionsof 250 150 and 50 120583gmL Experiments were performedunder laboratory conditions at 30∘C About 100 freshlyhatched second stage juveniles were suspended in 5mL ofeach diluted compound and incubated Distilled water withnematode larvae was taken as control The dead nematodeswere observed under an inverted binocularmicroscope Afteran incubation of 24 and 48 h percentage of mortality wascalculated Nematodes were considered dead if they did notmove when probed with a fine needle [30]

26 DPPH Radical Scavenging Activity The free radicalscavenging activities of themetal complexes were determinedby using DPPH free radical scavenging method according tothe literature [31] DPPH is a stable free radical containing anodd electron in its structure and usually utilized for detectionof the radical scavenging activity in chemical analysis Inthe spectrophotometric assay the ability to scavenge thestable free radical DPPH is measured by decrease in theabsorbance at 517 nm Each compound was dissolved inmethanol (10mg10mL) and it was used as stock solutionFrom the stock solutions 1mL of each compound solutionwith different concentrations (025120583gndash100 120583g) was addedto the 3mL of methanolic DPPH (0004) solution After30min the absorbance of the test compounds was taken at517 nm using UV-VIS spectrophotometer BHT was used asstandard DPPH solution was used as control without the testcompounds andmethanol was used as blankThe percentageof scavenging activity of DPPH free radical was measured byusing the following formula

Scavenging activity () = [(119860

119900minus 119860

119894)

119860

119900

] times 100 (1)

where 119860119900is the absorbance of the control and 119860

119894is the

absorbance of the sample

27 Cytotoxic Activity The human breast carcinoma cellline (MCF-7) human colon carcinoma cell line (COLO

205) and murine microphage cell line (Raw 2647) wereobtained from the National Centre for Cell Science (NCCS)Pune and grown in Dulbeccorsquos Modified Eagles Medium(DMEM) containing 10 fetal bovine serum (FBS) ampho-tericin (3 120583gmL) gentamycin (400 120583gmL) streptomycin(250 120583gmL) and penicillin (250 unitsmL) in a carbon diox-ide incubator at 5CO

2 About 700 cellswell were seeded in

96-well plate using culture medium the viability was testedusing trypan blue dye with help of haemocytometer and 95of viability was confirmed After 24 h the new medium withcompounds in the concentration of 100 10 and 1120583gmL wereadded at respective wells and kept in incubation for 48 hAfter incubation MTT assay was performed

271 MTT Assay After 48 h of the drug treatment themedium was changed again for all groups and 10120583L of MTT(5mgmL stock solution) was added and the plates wereincubated for an additional 4 h The medium was discardedand the formazan blue which was formed in the cells wasdissolved with 50120583L of DMSO The optical density wasmeasured on microplate spectrophotometer at a wavelengthof 570 nmThe percentage of cell inhibition was calculated byusing the following formula [32]

Growth inhibition = 100 minus (119860

119894

119860

119900

) times 100 (2)

where 119860119894is the absorbance of the sample and 119860

119900is the

absorbance of the control IC50values were determined using

Graph Pad Prism software

28 DNA Cleavage Activity The DNA cleavage activity ofmetal complexes was monitored by agarose gel electrophore-sis pUC19 plasmid was cultured isolated and used as DNAfor the experiment Test samples (1mgmL) were preparedin DMF 25 120583g of the test samples was added to the isolatedplasmid and incubated for 2 h at 37∘C After incubation30 120583L of plasmid DNA sample mixed with bromophenol bluedye (1 1) was loaded into the electrophoresis chamber wellsalong with the control DNA 5M FeSO

4(treated with DNA)

and standard DNA marker containing TAE buffer (484 gTris base pH 80 05M EDTA1 L) Finally it was loadedon to an agarose gel and electrophoresed at 50V constantvoltage up to 30min After the run gel was removed andstained with 1001 120583gmL ethidium bromide and image wastaken in Versadoc (Biorad) imaging system The results werecompared with standard DNA marker The same procedurewas followed in the presence of H

2O2also

3 Results and Discussion

All the Ni(II) complexes were colored stable and nonhygro-scopic in nature The complexes are insoluble in commonorganic solvents but soluble inDMF andDMSOThe elemen-tal analysis showed that the complexes have 1 2 stoichiome-try of the type [M(L

1ndash4)2]sdot119899H2O where L stands for singlydeprotonated ligands Molar conductance of the complexeswas measured in DMF The conductance values which are

4 Bioinorganic Chemistry and Applications

presented in the Table 1 indicate the nonelectrolytic natureof the complexes [33]

31 Determination of the Metal Content of the ComplexesKnown amount (0150 g) of complexes was decomposedwith concentrated nitric acid This process was repeatedtill the organic part of the complexes got completely lostThe excess nitric acid was expelled by evaporation withconcentrated sulphuric acid The Ni(II) and Zn(II) contentsof the complexes were determined as per the procedureavailable in the literature [34]

32 FTIR Spectra The FTIR spectra of the complexes arecompared with those of the ligands in order to determinethe coordination sites that may involve in chelation Theposition andor the intensities of bands are expected to bechanged while the coordination The most important IRbands of the metal complexes with probable assignments aregiven in Table 2 The Schiff base ligands showing a bandaround 1650ndash1620 cmminus1 is assigned to the (C=O) group ofthe chromone system Upon complexation the ](C=O) groupis shifted to 20ndash35 cmminus1 lower wavenumber region [35] Theligands show the most characteristic ](C=N) bands in theregion 1605ndash1563 cmminus1 In the spectra of their correspond-ing metal complexes this band appears at 25ndash45 cmminus1 tolower wavenumber region indicating the coordination of theazomethine nitrogen atom to the metal ion [36] A broadband appeared in HL

1and HL

3at 3241 and 3246 cmminus1

respectively and is attributed to the ](OndashH) group Theabsence of the band in the spectra of their correspondingmetal complexes is due to the involvement of oxygen atomof (OH) group coordination to the metal ion In HL

2ligand

a strong band appeared at 1365 cmminus1 and is due to the ](CndashO)of carboxylic group In its metal complexes it is shifted to 18ndash47 cmminus1 lower wavenumber region [37] Since SH stretchingfrequency band is very weak the peak corresponding toSH is not clearly observed in the case of HL

4ligand [38]

Presence of band around 3400 cmminus1 in all the complexes is theindication of water molecules present in the complexes Thepresence of oxygen and nitrogen in the coordination sphereis further confirmed by the presence of ](MndashN) and ](MndashO)bands at 400ndash600 cmminus1 regionThe FTIR results show that allSchiff base ligands act as tridentate chelating ligands

33 Electronic Spectra andMagneticMoments The electronicabsorption spectra of the Schiff base metal complexes insolid state were recorded at room temperature and theband positions of the absorption maxima band assignmentsligand field parameters and magnetic moment values arelisted in Table 3 The electronic spectra of [Ni(L

4)2]sdotH2O

and [Zn(L4)2]sdotH2O complexes are depicted in Figure 2

The electronic spectra of Ni(II) complexes displayed threeabsorption bands in the range 8000ndash9000 14000ndash16000 and20000ndash24000 cmminus1 Thus these bands may be assigned tothe three spin allowed transitions 3A

2g (F)rarr3T2g (F) (]1)

3A2g (F) rarr 3T

1g (F) (]2) and 3A

2g (F) rarr 3T1g (P) (]

3)

respectively characteristic of octahedral geometryThe values

of transition ratio ]2]1and 120573 lie in the range of 170ndash180

and 089ndash095 respectively providing further evidence foroctahedral geometry of Ni(II) complexes [39] The B valuesfor the complexes are lower than the free ion value therebyindicating orbital overlap anddelocalisation of d-orbitalsThe120573-values obtained are less than unity suggesting the covalentcharacter of the metal-ligand bonds All Ni(II) complexes areparamagnetic and the magnetic movement values at roomtemperature are in the range of 291ndash325 BM which is wellagreed with the reported octahedral Ni(II) complexes [40]All Zn(II) complexes showed two bands around 25000 and30000 cmminus1 and are attributed to the 119899 rarr 120587lowast and 120587 rarr120587

lowast transitions respectively Zn(II) complexes that are in d10configuration are diamagnetic and do not show any d-dtransitions

34 Thermal Analysis The thermogravimetric analysis(TGA) of the metal complexes was carried out within thetemperature range from room temperature to 1000∘C TheTG-DTA graphs of [Ni(L

4)2] and [Zn(L

4)2]sdotH2O complexes

are given in Figure 3 The TGA data and their assignments ofall the metal complexes are listed in Table 4 Metal complexesdecompose gradually with formation of respective metaloxides The TG graphs of [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Zn(L1)2]sdotH2O and [Zn(L

4)2]sdotH2O complexes decompose

in two to three steps The first step corresponds to the lossof lattice water molecule in the temperature range between30 and 140∘C with a weight loss of 2-3 In the second andthird steps the total loss of ligand molecules was observedin the temperature range between 160 and 850∘C leavingbehindmetal oxide as residueThe thermal decomposition ofremaining metal complexes ([Ni(L

1)2] [Ni(L

4)2] [Zn(L

2)2]

and [Zn(L3)2]) occurs in two to three steps Upon starting

heating these metal complexes losses of the organic moietiesof Schiff base ligands were observed in two to three successivesteps within the temperature range of 150ndash850∘C In all thecomplexes the final mass loss is due to the formation of metaloxides as residue

On the basis of all spectral data (elemental analysisFTIR electronic spectra and thermal analysis) the suggestedstructures of the complexes are shown in Figure 4

35 Powder XRD and SEM Studies Single crystals of thecomplexes could not be obtained because of their insolubilityin most organic solvents hence the powder diffraction datawere obtained for structural characterization The powderXRD patterns of all metal complexes were recorded in therange 2120579 = 10ndash50∘ The powder XRD pattern of [Ni(L

1)2]

and [Zn(L1)2]sdotH2O are presented in Figure 5 Observed and

calculated powder XRD data of [Ni(L1)2] and [Zn(L

1)2]sdotH2O

are given in Tables 5(a) and 5(b) Unit cell parameterswere found by using trial and error methods All complexesare triclinic with different unit cell parameters All metalcomplexes display sharp crystalline peaks except [Zn(L

2)2]

and [Zn(L4)2]sdotH2O these two complexes do not exhibit well-

defined crystalline peaks due to their amorphous natureThe unit cell parameters of metal complexes are as follows[Ni(L1)2] 119886 = 880 A 119887 = 852 A 119888 = 750 A 120572 = 9993∘

Bioinorganic Chemistry and Applications 5

Table 1 Elemental analysis and physical properties of metal complexes

Molecular formulaColour( yield)

found(cald) Molar conductivity

(Ohmminus1 cm2 molminus1)C H N S M(NiZn)

[Ni(L1)2] Brick red 6449 321 423 991 10[Ni(C16H10O3N)2] (71) (6545) (340) (477) (1000)[Ni(L2)2]sdotH2O Light green 6159 302 421 879 12[Ni(C17H10O4N)2]sdotH2O (62) (6175) (332) (424) (888)[Ni(L3)2]sdotH2O Brick red 6107 323 923 943 15[Ni(C15H9O3N2)2]sdotH2O (85) (6115) (339) (951) (997)[Ni(L4)2] Black 6221 309 461 930 921 14[Ni(C16H10O2NS)2] (82) (6206) (323) (452) (1034) (949)[Zn(L1)2]sdotH2O Orange 6291 352 462 1058 15[Zn(C16H10O3N)2]sdotH2O (88) (6280) (360) (458) (1070)[Zn(L2)2] Yellow 6279 315 425 995 11[Zn(C17H10O4N)2] (61) (6283) (308) (431) (1007)[Zn(L3)2] Brick red 6021 325 935 1051 18[Zn(C15H9O3N2)2] (87) (6046) (302) (940) (1098)[Zn(L4)2]sdotH2O Yellow 6022 335 421 1001 1031 20[Zn(C16H10O2NS)2]sdotH2O (73) (5968) (341) (435) (993) (1046)

Table 2 IR spectral data of ligands and their metal complexes (cmminus1)

Compound ](OH) ](C=O) (120574 pyrone) ](C=N) ](CO) (carboxylate) ](CndashS) ](MndashN) ](MndashO)HL1 3241 1643 1605HL2 1651 1605 1365HL3 3246 1647 1591HL4 1622 1597 790[Ni(L1)2] 1619 1563 467 586[Ni(L2)2]sdotH2O 1618 1570 1318 419 514[Ni(L3)2]sdotH2O 1615 1563 480 500[Ni(L4)2] 1598 1564 743 443 524[Zn(L1)2]sdotH2O 1614 1574 460 599[Zn(L2)2] 1615 1563 1347 480 500[Zn(L3)2] 1615 1563 488 521[Zn(L4)2]sdotH2O 1609 1581 751 441 505

120573 = 11671

∘ 120574 = 9001∘ and 119881 = 562 (A)3 [Ni(L2)2]sdotH2O

119886 = 824 A 119887 = 924 A 119888 = 732 A 120572 = 10412∘ 120573 = 12444∘120574 = 9804

∘ and 119881 = 557 (A)3 [Ni(L3)2]sdotH2O 119886 = 940 A

119887 = 920 A 119888 = 846 A 120572 = 9745∘ 120573 = 10738∘ 120574 = 9145∘and 119881 = 731 (A)3 [Ni(L

4)2] 119886 = 773 A 119887 = 824 A

119888 = 849 A 120572 = 9830∘ 120573 = 10476∘ 120574 = 9055∘ and119881 = 540 (A)3 [Zn(L

1)2]sdotH2O 119886 = 960 A 119887 = 994 A

119888 = 889 A 120572 = 10234∘ 120573 = 10969∘ 120574 = 9394∘ and119881 = 848 (A)3 [Zn(L

3)2] 119886 = 876 A 119887 = 904 A 119888 = 861 A

120572 = 10578

∘ 120573 = 10302∘ 120574 = 9021∘ and 119881 = 682 (A)3The average crystallite sizes (119863) of the metal complexes arecalculated from the Scherrer formula [41]

119863 =

09120582

120573 cos 120579 (3)

where 120582 is the X-ray wavelength 120573 is the full width at halfmaximum of prominent intensity peak and 120579 is the diffrac-tion angle The [Ni(L

1)2] [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Ni(L4)2] [Zn(L

1)2]sdotH2O and [Zn(L

3)2] complexes have an

average crystallite size of 70 17 16 27 42 and 53 nm respec-tively suggesting that the complexes are in nanocrystallinephase

The SEM (Scanning Electron Microscope) is used toevaluate the morphology and particle size of the compoundsThe SEM photographs of [Ni(L

3)2]sdotH2O and [Ni(L

4)2] are

shown in Figure 6 The SEM micrographs show the agglom-erate particles of the complexes In case of [Ni(L

3)2]sdotH2O

and [Ni(L4)2] complexes some agglomerates appear to have

tiny needles while the other agglomerates appear to be ofspherical plates like morphologies

6 Bioinorganic Chemistry and Applications

Table 3 Electronic magnetic and ligand field parameters of Ni(II) complexes

Compound Absorption maxima(cmminus1) Tentative assignments Magnetic moment

(BM)]2]1

10Dq(cmminus1)

B(cmminus1)

120573

LFSE(kJsdotmolminus1)

[Ni(L1)2]85321520024900

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

312 178 8532 966 092 12250

[Ni( L2)2]sdotH2O87871600024390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

318 182 8787 935 089 12619

[Ni(L3)2]sdotH2O8313147052083324390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

325 176 8313 943 090 11940

[Ni(L4)2]86281631324570

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

291 189 8628 999 095 12392

Table 4 Thermal analysis results of metal complexes

Compound Temperature (∘C) Found (cald) Assignment

[Ni(L1)2][Ni(C16H10O3N)2]

180ndash420 1938 (1836) C6H4ON

421ndash718 6855 (6902) C26H16O5N

gt718 1207 (1262) NiO

[Ni(L2)2]sdotH2O[Ni(C17H10O4N)2]sdotH2O

30ndash90 283 (272) H2O335ndash478 6071 (6205) C24H14O5N2

479ndash849 2393 (2361) C10H6O2

gt849 1253 (1162) NiO

[Ni(L3)2]sdotH2O[Ni(C15H9O3N2)2]sdotH2O

30ndash65 309 (296) H2O180ndash879 8340 (8473) C30H18O5N4

gt880 1351 (1231) NiO

[Ni(L4)2][Ni(C16H10O2NS)2]

171ndash410 4591 (4525) C16H10O2NS411ndash670 4214 (4267) C16H10ONSgt670 1195 (1207) NiO

[Zn(L1)2]sdotH2O[Zn(C16H10O3N)2]sdotH2O

30ndash135 245 (295) H2O194ndash422 2495 (2592) C10H6O2

423ndash790 5948 (5809) C22H14O3N2

gt791 1312 (1304) ZnO

[Zn(L2)2][Zn(C17H10O4N)2]

195ndash265 1555 (1601) C7H4O266ndash661 6976 (7146) C27H16O4N2

gt662 1469 (1253) ZnO

[Zn(L3)2][Zn(C15H9O3N2)2]

157ndash192 1091 (1293) C5H3N193ndash485 2865 (2922) C10H6O2N486ndash835 4603 (4418) C15H9O3N2

gt836 1441 (1367) ZnO

[Zn(L4)2]sdotH2O[Zn(C16H10O2NS)2]sdotH2O

30ndash124 241 (279) H2O165ndash348 2741 (2673) C10H6O2N389ndash632 5698 (5784) C22H14ONS2gt632 1320 (1264) ZnO

Bioinorganic Chemistry and Applications 7

Table 5 Observed and calculated powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L1)2]sdotH2O

(a)

S number 2120579

Δ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1057 1057 0 83627 83627 0 1 02 1129 1129 0 78314 78314 1 0 03 1344 1344 0 65805 65805 0 0 14 1479 1479 0 59847 59847 minus1 1 05 1575 1575 0 56205 56205 minus1 minus1 16 1779 1779 0 49805 49805 minus1 1 17 1885 1868 0164 47046 47455 0 1 18 2116 2122 minus006 41962 41845 1 0 19 2214 2206 0074 40121 40255 1 minus1 110 2405 2407 minus0013 36968 36948 minus1 0 211 2504 2499 0054 35533 35608 1 2 012 2633 2635 minus0017 3382 33799 minus1 2 113 281 2804 0061 31731 31799 minus1 1 214 3265 3265 0 27404 27405 2 2 015 3506 3507 minus0012 25575 25566 minus3 1 016 3892 3886 0054 23124 23155 minus2 3 117 4389 4395 minus0058 20612 20586 minus1 3 218 4513 4516 minus0033 20076 20062 minus2 minus3 3

(b)

S number 2120579 valuesΔ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1258 1258 0 70315 70315 1 1 02 1381 1381 0 64077 64077 minus1 0 13 1573 1573 0 56299 56299 1 0 14 1735 1735 0 51064 51064 minus1 1 15 2075 2077 minus0017 42777 42742 minus1 3 06 2409 2413 minus0031 36907 36859 minus1 minus3 27 2532 2531 0012 35141 35158 2 2 08 2793 2797 minus0038 31916 31873 minus1 minus4 29 3015 3016 minus0008 29620 29612 0 minus3 310 3192 3190 0021 28015 28033 2 minus5 211 3443 3445 minus0017 26028 26016 minus1 5 012 3605 3606 minus0008 24892 24886 minus1 0 313 4275 4283 minus0081 21137 21099 3 1 2

36 Fluorescence Spectra The fluorescence characteristics ofmetal complexes were studied at room temperature in solidstate In metal complexes metal to ligand coordination maylead to significant changes of the fluorescence properties ofthe ligand including increase or decrease of the intensityemission wavelength shift quenching of the fluorescence orappearance of new emissions [42] The fluorescence spectraof HL

1ligand and its metal (Ni(II) and Zn(II)) complexes

were depicted in Figure 7 The Ni(II) and Zn(II) complexesof HL

1were characterised by emission bands around (522

569) nm and (458 644) nm upon photo excitation at 453and 357 nm respectively The Ni(II) complex of HL

2exhibits

emission bands at 449 and 524 nm Zn(II) complex of HL2

does not show any emission spectra The Ni(II) and Zn(II)complexes of HL

3were characterised by an emission bands

at (504 570 and 668) and 419 nm respectively The Ni(II)and Zn(II) complexes of HL

4exhibit emission bands around

539 and 613 nm respectively From the results red shift andquenching of the metal ions was observed in the case ofligands and its metal complexes

37 Antimicrobial Activity Theminimum inhibitory concen-trations (MIC) of the complexes compared with the ligandsand standard drugs are listed in Table 6 The results indicatethat themetal complexes displayedmore antibacterial activitycompared to the parent ligands under similar experimental

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Theoretical ChemistryJournal of

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Journal of

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Journal of

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Quantum Chemistry

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Organic Chemistry International

ElectrochemistryInternational Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 3: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Bioinorganic Chemistry and Applications 3

bacterial growth (no turbidity) in comparison to control wasregarded as MIC

25 Nematicidal Activity Root knot nematodeMeloidogyneincognita is major plant parasitic nematodes affecting quan-tity and quality of the crop production in many annual andperennial crops Meloidogyne nematode can develop gallsand lesions in the roots thereby causing stunted growth ofthe plants Some of the chemicals can be used to controlnematodes [29]

Nematicidal activity of the complexes was carried outon Meloidogyne incognita Fresh egg masses of Meloidogyneincognita are collected from stock culture maintained ontomato (Lycopersicon esculentum) root tissues and kept inwater for egg hatchingThe eggs suspensions were poured ona cotton wool filter paper and incubated at 30∘C to obtainfreshly hatched juveniles (J2) Juveniles collected within48 h were used for screening nematicidal activity of thecompounds

The compounds were initially dissolved in dimethyl sul-foxide (DMSO) and then in distilled water to make dilutionsof 250 150 and 50 120583gmL Experiments were performedunder laboratory conditions at 30∘C About 100 freshlyhatched second stage juveniles were suspended in 5mL ofeach diluted compound and incubated Distilled water withnematode larvae was taken as control The dead nematodeswere observed under an inverted binocularmicroscope Afteran incubation of 24 and 48 h percentage of mortality wascalculated Nematodes were considered dead if they did notmove when probed with a fine needle [30]

26 DPPH Radical Scavenging Activity The free radicalscavenging activities of themetal complexes were determinedby using DPPH free radical scavenging method according tothe literature [31] DPPH is a stable free radical containing anodd electron in its structure and usually utilized for detectionof the radical scavenging activity in chemical analysis Inthe spectrophotometric assay the ability to scavenge thestable free radical DPPH is measured by decrease in theabsorbance at 517 nm Each compound was dissolved inmethanol (10mg10mL) and it was used as stock solutionFrom the stock solutions 1mL of each compound solutionwith different concentrations (025120583gndash100 120583g) was addedto the 3mL of methanolic DPPH (0004) solution After30min the absorbance of the test compounds was taken at517 nm using UV-VIS spectrophotometer BHT was used asstandard DPPH solution was used as control without the testcompounds andmethanol was used as blankThe percentageof scavenging activity of DPPH free radical was measured byusing the following formula

Scavenging activity () = [(119860

119900minus 119860

119894)

119860

119900

] times 100 (1)

where 119860119900is the absorbance of the control and 119860

119894is the

absorbance of the sample

27 Cytotoxic Activity The human breast carcinoma cellline (MCF-7) human colon carcinoma cell line (COLO

205) and murine microphage cell line (Raw 2647) wereobtained from the National Centre for Cell Science (NCCS)Pune and grown in Dulbeccorsquos Modified Eagles Medium(DMEM) containing 10 fetal bovine serum (FBS) ampho-tericin (3 120583gmL) gentamycin (400 120583gmL) streptomycin(250 120583gmL) and penicillin (250 unitsmL) in a carbon diox-ide incubator at 5CO

2 About 700 cellswell were seeded in

96-well plate using culture medium the viability was testedusing trypan blue dye with help of haemocytometer and 95of viability was confirmed After 24 h the new medium withcompounds in the concentration of 100 10 and 1120583gmL wereadded at respective wells and kept in incubation for 48 hAfter incubation MTT assay was performed

271 MTT Assay After 48 h of the drug treatment themedium was changed again for all groups and 10120583L of MTT(5mgmL stock solution) was added and the plates wereincubated for an additional 4 h The medium was discardedand the formazan blue which was formed in the cells wasdissolved with 50120583L of DMSO The optical density wasmeasured on microplate spectrophotometer at a wavelengthof 570 nmThe percentage of cell inhibition was calculated byusing the following formula [32]

Growth inhibition = 100 minus (119860

119894

119860

119900

) times 100 (2)

where 119860119894is the absorbance of the sample and 119860

119900is the

absorbance of the control IC50values were determined using

Graph Pad Prism software

28 DNA Cleavage Activity The DNA cleavage activity ofmetal complexes was monitored by agarose gel electrophore-sis pUC19 plasmid was cultured isolated and used as DNAfor the experiment Test samples (1mgmL) were preparedin DMF 25 120583g of the test samples was added to the isolatedplasmid and incubated for 2 h at 37∘C After incubation30 120583L of plasmid DNA sample mixed with bromophenol bluedye (1 1) was loaded into the electrophoresis chamber wellsalong with the control DNA 5M FeSO

4(treated with DNA)

and standard DNA marker containing TAE buffer (484 gTris base pH 80 05M EDTA1 L) Finally it was loadedon to an agarose gel and electrophoresed at 50V constantvoltage up to 30min After the run gel was removed andstained with 1001 120583gmL ethidium bromide and image wastaken in Versadoc (Biorad) imaging system The results werecompared with standard DNA marker The same procedurewas followed in the presence of H

2O2also

3 Results and Discussion

All the Ni(II) complexes were colored stable and nonhygro-scopic in nature The complexes are insoluble in commonorganic solvents but soluble inDMF andDMSOThe elemen-tal analysis showed that the complexes have 1 2 stoichiome-try of the type [M(L

1ndash4)2]sdot119899H2O where L stands for singlydeprotonated ligands Molar conductance of the complexeswas measured in DMF The conductance values which are

4 Bioinorganic Chemistry and Applications

presented in the Table 1 indicate the nonelectrolytic natureof the complexes [33]

31 Determination of the Metal Content of the ComplexesKnown amount (0150 g) of complexes was decomposedwith concentrated nitric acid This process was repeatedtill the organic part of the complexes got completely lostThe excess nitric acid was expelled by evaporation withconcentrated sulphuric acid The Ni(II) and Zn(II) contentsof the complexes were determined as per the procedureavailable in the literature [34]

32 FTIR Spectra The FTIR spectra of the complexes arecompared with those of the ligands in order to determinethe coordination sites that may involve in chelation Theposition andor the intensities of bands are expected to bechanged while the coordination The most important IRbands of the metal complexes with probable assignments aregiven in Table 2 The Schiff base ligands showing a bandaround 1650ndash1620 cmminus1 is assigned to the (C=O) group ofthe chromone system Upon complexation the ](C=O) groupis shifted to 20ndash35 cmminus1 lower wavenumber region [35] Theligands show the most characteristic ](C=N) bands in theregion 1605ndash1563 cmminus1 In the spectra of their correspond-ing metal complexes this band appears at 25ndash45 cmminus1 tolower wavenumber region indicating the coordination of theazomethine nitrogen atom to the metal ion [36] A broadband appeared in HL

1and HL

3at 3241 and 3246 cmminus1

respectively and is attributed to the ](OndashH) group Theabsence of the band in the spectra of their correspondingmetal complexes is due to the involvement of oxygen atomof (OH) group coordination to the metal ion In HL

2ligand

a strong band appeared at 1365 cmminus1 and is due to the ](CndashO)of carboxylic group In its metal complexes it is shifted to 18ndash47 cmminus1 lower wavenumber region [37] Since SH stretchingfrequency band is very weak the peak corresponding toSH is not clearly observed in the case of HL

4ligand [38]

Presence of band around 3400 cmminus1 in all the complexes is theindication of water molecules present in the complexes Thepresence of oxygen and nitrogen in the coordination sphereis further confirmed by the presence of ](MndashN) and ](MndashO)bands at 400ndash600 cmminus1 regionThe FTIR results show that allSchiff base ligands act as tridentate chelating ligands

33 Electronic Spectra andMagneticMoments The electronicabsorption spectra of the Schiff base metal complexes insolid state were recorded at room temperature and theband positions of the absorption maxima band assignmentsligand field parameters and magnetic moment values arelisted in Table 3 The electronic spectra of [Ni(L

4)2]sdotH2O

and [Zn(L4)2]sdotH2O complexes are depicted in Figure 2

The electronic spectra of Ni(II) complexes displayed threeabsorption bands in the range 8000ndash9000 14000ndash16000 and20000ndash24000 cmminus1 Thus these bands may be assigned tothe three spin allowed transitions 3A

2g (F)rarr3T2g (F) (]1)

3A2g (F) rarr 3T

1g (F) (]2) and 3A

2g (F) rarr 3T1g (P) (]

3)

respectively characteristic of octahedral geometryThe values

of transition ratio ]2]1and 120573 lie in the range of 170ndash180

and 089ndash095 respectively providing further evidence foroctahedral geometry of Ni(II) complexes [39] The B valuesfor the complexes are lower than the free ion value therebyindicating orbital overlap anddelocalisation of d-orbitalsThe120573-values obtained are less than unity suggesting the covalentcharacter of the metal-ligand bonds All Ni(II) complexes areparamagnetic and the magnetic movement values at roomtemperature are in the range of 291ndash325 BM which is wellagreed with the reported octahedral Ni(II) complexes [40]All Zn(II) complexes showed two bands around 25000 and30000 cmminus1 and are attributed to the 119899 rarr 120587lowast and 120587 rarr120587

lowast transitions respectively Zn(II) complexes that are in d10configuration are diamagnetic and do not show any d-dtransitions

34 Thermal Analysis The thermogravimetric analysis(TGA) of the metal complexes was carried out within thetemperature range from room temperature to 1000∘C TheTG-DTA graphs of [Ni(L

4)2] and [Zn(L

4)2]sdotH2O complexes

are given in Figure 3 The TGA data and their assignments ofall the metal complexes are listed in Table 4 Metal complexesdecompose gradually with formation of respective metaloxides The TG graphs of [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Zn(L1)2]sdotH2O and [Zn(L

4)2]sdotH2O complexes decompose

in two to three steps The first step corresponds to the lossof lattice water molecule in the temperature range between30 and 140∘C with a weight loss of 2-3 In the second andthird steps the total loss of ligand molecules was observedin the temperature range between 160 and 850∘C leavingbehindmetal oxide as residueThe thermal decomposition ofremaining metal complexes ([Ni(L

1)2] [Ni(L

4)2] [Zn(L

2)2]

and [Zn(L3)2]) occurs in two to three steps Upon starting

heating these metal complexes losses of the organic moietiesof Schiff base ligands were observed in two to three successivesteps within the temperature range of 150ndash850∘C In all thecomplexes the final mass loss is due to the formation of metaloxides as residue

On the basis of all spectral data (elemental analysisFTIR electronic spectra and thermal analysis) the suggestedstructures of the complexes are shown in Figure 4

35 Powder XRD and SEM Studies Single crystals of thecomplexes could not be obtained because of their insolubilityin most organic solvents hence the powder diffraction datawere obtained for structural characterization The powderXRD patterns of all metal complexes were recorded in therange 2120579 = 10ndash50∘ The powder XRD pattern of [Ni(L

1)2]

and [Zn(L1)2]sdotH2O are presented in Figure 5 Observed and

calculated powder XRD data of [Ni(L1)2] and [Zn(L

1)2]sdotH2O

are given in Tables 5(a) and 5(b) Unit cell parameterswere found by using trial and error methods All complexesare triclinic with different unit cell parameters All metalcomplexes display sharp crystalline peaks except [Zn(L

2)2]

and [Zn(L4)2]sdotH2O these two complexes do not exhibit well-

defined crystalline peaks due to their amorphous natureThe unit cell parameters of metal complexes are as follows[Ni(L1)2] 119886 = 880 A 119887 = 852 A 119888 = 750 A 120572 = 9993∘

Bioinorganic Chemistry and Applications 5

Table 1 Elemental analysis and physical properties of metal complexes

Molecular formulaColour( yield)

found(cald) Molar conductivity

(Ohmminus1 cm2 molminus1)C H N S M(NiZn)

[Ni(L1)2] Brick red 6449 321 423 991 10[Ni(C16H10O3N)2] (71) (6545) (340) (477) (1000)[Ni(L2)2]sdotH2O Light green 6159 302 421 879 12[Ni(C17H10O4N)2]sdotH2O (62) (6175) (332) (424) (888)[Ni(L3)2]sdotH2O Brick red 6107 323 923 943 15[Ni(C15H9O3N2)2]sdotH2O (85) (6115) (339) (951) (997)[Ni(L4)2] Black 6221 309 461 930 921 14[Ni(C16H10O2NS)2] (82) (6206) (323) (452) (1034) (949)[Zn(L1)2]sdotH2O Orange 6291 352 462 1058 15[Zn(C16H10O3N)2]sdotH2O (88) (6280) (360) (458) (1070)[Zn(L2)2] Yellow 6279 315 425 995 11[Zn(C17H10O4N)2] (61) (6283) (308) (431) (1007)[Zn(L3)2] Brick red 6021 325 935 1051 18[Zn(C15H9O3N2)2] (87) (6046) (302) (940) (1098)[Zn(L4)2]sdotH2O Yellow 6022 335 421 1001 1031 20[Zn(C16H10O2NS)2]sdotH2O (73) (5968) (341) (435) (993) (1046)

Table 2 IR spectral data of ligands and their metal complexes (cmminus1)

Compound ](OH) ](C=O) (120574 pyrone) ](C=N) ](CO) (carboxylate) ](CndashS) ](MndashN) ](MndashO)HL1 3241 1643 1605HL2 1651 1605 1365HL3 3246 1647 1591HL4 1622 1597 790[Ni(L1)2] 1619 1563 467 586[Ni(L2)2]sdotH2O 1618 1570 1318 419 514[Ni(L3)2]sdotH2O 1615 1563 480 500[Ni(L4)2] 1598 1564 743 443 524[Zn(L1)2]sdotH2O 1614 1574 460 599[Zn(L2)2] 1615 1563 1347 480 500[Zn(L3)2] 1615 1563 488 521[Zn(L4)2]sdotH2O 1609 1581 751 441 505

120573 = 11671

∘ 120574 = 9001∘ and 119881 = 562 (A)3 [Ni(L2)2]sdotH2O

119886 = 824 A 119887 = 924 A 119888 = 732 A 120572 = 10412∘ 120573 = 12444∘120574 = 9804

∘ and 119881 = 557 (A)3 [Ni(L3)2]sdotH2O 119886 = 940 A

119887 = 920 A 119888 = 846 A 120572 = 9745∘ 120573 = 10738∘ 120574 = 9145∘and 119881 = 731 (A)3 [Ni(L

4)2] 119886 = 773 A 119887 = 824 A

119888 = 849 A 120572 = 9830∘ 120573 = 10476∘ 120574 = 9055∘ and119881 = 540 (A)3 [Zn(L

1)2]sdotH2O 119886 = 960 A 119887 = 994 A

119888 = 889 A 120572 = 10234∘ 120573 = 10969∘ 120574 = 9394∘ and119881 = 848 (A)3 [Zn(L

3)2] 119886 = 876 A 119887 = 904 A 119888 = 861 A

120572 = 10578

∘ 120573 = 10302∘ 120574 = 9021∘ and 119881 = 682 (A)3The average crystallite sizes (119863) of the metal complexes arecalculated from the Scherrer formula [41]

119863 =

09120582

120573 cos 120579 (3)

where 120582 is the X-ray wavelength 120573 is the full width at halfmaximum of prominent intensity peak and 120579 is the diffrac-tion angle The [Ni(L

1)2] [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Ni(L4)2] [Zn(L

1)2]sdotH2O and [Zn(L

3)2] complexes have an

average crystallite size of 70 17 16 27 42 and 53 nm respec-tively suggesting that the complexes are in nanocrystallinephase

The SEM (Scanning Electron Microscope) is used toevaluate the morphology and particle size of the compoundsThe SEM photographs of [Ni(L

3)2]sdotH2O and [Ni(L

4)2] are

shown in Figure 6 The SEM micrographs show the agglom-erate particles of the complexes In case of [Ni(L

3)2]sdotH2O

and [Ni(L4)2] complexes some agglomerates appear to have

tiny needles while the other agglomerates appear to be ofspherical plates like morphologies

6 Bioinorganic Chemistry and Applications

Table 3 Electronic magnetic and ligand field parameters of Ni(II) complexes

Compound Absorption maxima(cmminus1) Tentative assignments Magnetic moment

(BM)]2]1

10Dq(cmminus1)

B(cmminus1)

120573

LFSE(kJsdotmolminus1)

[Ni(L1)2]85321520024900

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

312 178 8532 966 092 12250

[Ni( L2)2]sdotH2O87871600024390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

318 182 8787 935 089 12619

[Ni(L3)2]sdotH2O8313147052083324390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

325 176 8313 943 090 11940

[Ni(L4)2]86281631324570

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

291 189 8628 999 095 12392

Table 4 Thermal analysis results of metal complexes

Compound Temperature (∘C) Found (cald) Assignment

[Ni(L1)2][Ni(C16H10O3N)2]

180ndash420 1938 (1836) C6H4ON

421ndash718 6855 (6902) C26H16O5N

gt718 1207 (1262) NiO

[Ni(L2)2]sdotH2O[Ni(C17H10O4N)2]sdotH2O

30ndash90 283 (272) H2O335ndash478 6071 (6205) C24H14O5N2

479ndash849 2393 (2361) C10H6O2

gt849 1253 (1162) NiO

[Ni(L3)2]sdotH2O[Ni(C15H9O3N2)2]sdotH2O

30ndash65 309 (296) H2O180ndash879 8340 (8473) C30H18O5N4

gt880 1351 (1231) NiO

[Ni(L4)2][Ni(C16H10O2NS)2]

171ndash410 4591 (4525) C16H10O2NS411ndash670 4214 (4267) C16H10ONSgt670 1195 (1207) NiO

[Zn(L1)2]sdotH2O[Zn(C16H10O3N)2]sdotH2O

30ndash135 245 (295) H2O194ndash422 2495 (2592) C10H6O2

423ndash790 5948 (5809) C22H14O3N2

gt791 1312 (1304) ZnO

[Zn(L2)2][Zn(C17H10O4N)2]

195ndash265 1555 (1601) C7H4O266ndash661 6976 (7146) C27H16O4N2

gt662 1469 (1253) ZnO

[Zn(L3)2][Zn(C15H9O3N2)2]

157ndash192 1091 (1293) C5H3N193ndash485 2865 (2922) C10H6O2N486ndash835 4603 (4418) C15H9O3N2

gt836 1441 (1367) ZnO

[Zn(L4)2]sdotH2O[Zn(C16H10O2NS)2]sdotH2O

30ndash124 241 (279) H2O165ndash348 2741 (2673) C10H6O2N389ndash632 5698 (5784) C22H14ONS2gt632 1320 (1264) ZnO

Bioinorganic Chemistry and Applications 7

Table 5 Observed and calculated powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L1)2]sdotH2O

(a)

S number 2120579

Δ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1057 1057 0 83627 83627 0 1 02 1129 1129 0 78314 78314 1 0 03 1344 1344 0 65805 65805 0 0 14 1479 1479 0 59847 59847 minus1 1 05 1575 1575 0 56205 56205 minus1 minus1 16 1779 1779 0 49805 49805 minus1 1 17 1885 1868 0164 47046 47455 0 1 18 2116 2122 minus006 41962 41845 1 0 19 2214 2206 0074 40121 40255 1 minus1 110 2405 2407 minus0013 36968 36948 minus1 0 211 2504 2499 0054 35533 35608 1 2 012 2633 2635 minus0017 3382 33799 minus1 2 113 281 2804 0061 31731 31799 minus1 1 214 3265 3265 0 27404 27405 2 2 015 3506 3507 minus0012 25575 25566 minus3 1 016 3892 3886 0054 23124 23155 minus2 3 117 4389 4395 minus0058 20612 20586 minus1 3 218 4513 4516 minus0033 20076 20062 minus2 minus3 3

(b)

S number 2120579 valuesΔ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1258 1258 0 70315 70315 1 1 02 1381 1381 0 64077 64077 minus1 0 13 1573 1573 0 56299 56299 1 0 14 1735 1735 0 51064 51064 minus1 1 15 2075 2077 minus0017 42777 42742 minus1 3 06 2409 2413 minus0031 36907 36859 minus1 minus3 27 2532 2531 0012 35141 35158 2 2 08 2793 2797 minus0038 31916 31873 minus1 minus4 29 3015 3016 minus0008 29620 29612 0 minus3 310 3192 3190 0021 28015 28033 2 minus5 211 3443 3445 minus0017 26028 26016 minus1 5 012 3605 3606 minus0008 24892 24886 minus1 0 313 4275 4283 minus0081 21137 21099 3 1 2

36 Fluorescence Spectra The fluorescence characteristics ofmetal complexes were studied at room temperature in solidstate In metal complexes metal to ligand coordination maylead to significant changes of the fluorescence properties ofthe ligand including increase or decrease of the intensityemission wavelength shift quenching of the fluorescence orappearance of new emissions [42] The fluorescence spectraof HL

1ligand and its metal (Ni(II) and Zn(II)) complexes

were depicted in Figure 7 The Ni(II) and Zn(II) complexesof HL

1were characterised by emission bands around (522

569) nm and (458 644) nm upon photo excitation at 453and 357 nm respectively The Ni(II) complex of HL

2exhibits

emission bands at 449 and 524 nm Zn(II) complex of HL2

does not show any emission spectra The Ni(II) and Zn(II)complexes of HL

3were characterised by an emission bands

at (504 570 and 668) and 419 nm respectively The Ni(II)and Zn(II) complexes of HL

4exhibit emission bands around

539 and 613 nm respectively From the results red shift andquenching of the metal ions was observed in the case ofligands and its metal complexes

37 Antimicrobial Activity Theminimum inhibitory concen-trations (MIC) of the complexes compared with the ligandsand standard drugs are listed in Table 6 The results indicatethat themetal complexes displayedmore antibacterial activitycompared to the parent ligands under similar experimental

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 4: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

4 Bioinorganic Chemistry and Applications

presented in the Table 1 indicate the nonelectrolytic natureof the complexes [33]

31 Determination of the Metal Content of the ComplexesKnown amount (0150 g) of complexes was decomposedwith concentrated nitric acid This process was repeatedtill the organic part of the complexes got completely lostThe excess nitric acid was expelled by evaporation withconcentrated sulphuric acid The Ni(II) and Zn(II) contentsof the complexes were determined as per the procedureavailable in the literature [34]

32 FTIR Spectra The FTIR spectra of the complexes arecompared with those of the ligands in order to determinethe coordination sites that may involve in chelation Theposition andor the intensities of bands are expected to bechanged while the coordination The most important IRbands of the metal complexes with probable assignments aregiven in Table 2 The Schiff base ligands showing a bandaround 1650ndash1620 cmminus1 is assigned to the (C=O) group ofthe chromone system Upon complexation the ](C=O) groupis shifted to 20ndash35 cmminus1 lower wavenumber region [35] Theligands show the most characteristic ](C=N) bands in theregion 1605ndash1563 cmminus1 In the spectra of their correspond-ing metal complexes this band appears at 25ndash45 cmminus1 tolower wavenumber region indicating the coordination of theazomethine nitrogen atom to the metal ion [36] A broadband appeared in HL

1and HL

3at 3241 and 3246 cmminus1

respectively and is attributed to the ](OndashH) group Theabsence of the band in the spectra of their correspondingmetal complexes is due to the involvement of oxygen atomof (OH) group coordination to the metal ion In HL

2ligand

a strong band appeared at 1365 cmminus1 and is due to the ](CndashO)of carboxylic group In its metal complexes it is shifted to 18ndash47 cmminus1 lower wavenumber region [37] Since SH stretchingfrequency band is very weak the peak corresponding toSH is not clearly observed in the case of HL

4ligand [38]

Presence of band around 3400 cmminus1 in all the complexes is theindication of water molecules present in the complexes Thepresence of oxygen and nitrogen in the coordination sphereis further confirmed by the presence of ](MndashN) and ](MndashO)bands at 400ndash600 cmminus1 regionThe FTIR results show that allSchiff base ligands act as tridentate chelating ligands

33 Electronic Spectra andMagneticMoments The electronicabsorption spectra of the Schiff base metal complexes insolid state were recorded at room temperature and theband positions of the absorption maxima band assignmentsligand field parameters and magnetic moment values arelisted in Table 3 The electronic spectra of [Ni(L

4)2]sdotH2O

and [Zn(L4)2]sdotH2O complexes are depicted in Figure 2

The electronic spectra of Ni(II) complexes displayed threeabsorption bands in the range 8000ndash9000 14000ndash16000 and20000ndash24000 cmminus1 Thus these bands may be assigned tothe three spin allowed transitions 3A

2g (F)rarr3T2g (F) (]1)

3A2g (F) rarr 3T

1g (F) (]2) and 3A

2g (F) rarr 3T1g (P) (]

3)

respectively characteristic of octahedral geometryThe values

of transition ratio ]2]1and 120573 lie in the range of 170ndash180

and 089ndash095 respectively providing further evidence foroctahedral geometry of Ni(II) complexes [39] The B valuesfor the complexes are lower than the free ion value therebyindicating orbital overlap anddelocalisation of d-orbitalsThe120573-values obtained are less than unity suggesting the covalentcharacter of the metal-ligand bonds All Ni(II) complexes areparamagnetic and the magnetic movement values at roomtemperature are in the range of 291ndash325 BM which is wellagreed with the reported octahedral Ni(II) complexes [40]All Zn(II) complexes showed two bands around 25000 and30000 cmminus1 and are attributed to the 119899 rarr 120587lowast and 120587 rarr120587

lowast transitions respectively Zn(II) complexes that are in d10configuration are diamagnetic and do not show any d-dtransitions

34 Thermal Analysis The thermogravimetric analysis(TGA) of the metal complexes was carried out within thetemperature range from room temperature to 1000∘C TheTG-DTA graphs of [Ni(L

4)2] and [Zn(L

4)2]sdotH2O complexes

are given in Figure 3 The TGA data and their assignments ofall the metal complexes are listed in Table 4 Metal complexesdecompose gradually with formation of respective metaloxides The TG graphs of [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Zn(L1)2]sdotH2O and [Zn(L

4)2]sdotH2O complexes decompose

in two to three steps The first step corresponds to the lossof lattice water molecule in the temperature range between30 and 140∘C with a weight loss of 2-3 In the second andthird steps the total loss of ligand molecules was observedin the temperature range between 160 and 850∘C leavingbehindmetal oxide as residueThe thermal decomposition ofremaining metal complexes ([Ni(L

1)2] [Ni(L

4)2] [Zn(L

2)2]

and [Zn(L3)2]) occurs in two to three steps Upon starting

heating these metal complexes losses of the organic moietiesof Schiff base ligands were observed in two to three successivesteps within the temperature range of 150ndash850∘C In all thecomplexes the final mass loss is due to the formation of metaloxides as residue

On the basis of all spectral data (elemental analysisFTIR electronic spectra and thermal analysis) the suggestedstructures of the complexes are shown in Figure 4

35 Powder XRD and SEM Studies Single crystals of thecomplexes could not be obtained because of their insolubilityin most organic solvents hence the powder diffraction datawere obtained for structural characterization The powderXRD patterns of all metal complexes were recorded in therange 2120579 = 10ndash50∘ The powder XRD pattern of [Ni(L

1)2]

and [Zn(L1)2]sdotH2O are presented in Figure 5 Observed and

calculated powder XRD data of [Ni(L1)2] and [Zn(L

1)2]sdotH2O

are given in Tables 5(a) and 5(b) Unit cell parameterswere found by using trial and error methods All complexesare triclinic with different unit cell parameters All metalcomplexes display sharp crystalline peaks except [Zn(L

2)2]

and [Zn(L4)2]sdotH2O these two complexes do not exhibit well-

defined crystalline peaks due to their amorphous natureThe unit cell parameters of metal complexes are as follows[Ni(L1)2] 119886 = 880 A 119887 = 852 A 119888 = 750 A 120572 = 9993∘

Bioinorganic Chemistry and Applications 5

Table 1 Elemental analysis and physical properties of metal complexes

Molecular formulaColour( yield)

found(cald) Molar conductivity

(Ohmminus1 cm2 molminus1)C H N S M(NiZn)

[Ni(L1)2] Brick red 6449 321 423 991 10[Ni(C16H10O3N)2] (71) (6545) (340) (477) (1000)[Ni(L2)2]sdotH2O Light green 6159 302 421 879 12[Ni(C17H10O4N)2]sdotH2O (62) (6175) (332) (424) (888)[Ni(L3)2]sdotH2O Brick red 6107 323 923 943 15[Ni(C15H9O3N2)2]sdotH2O (85) (6115) (339) (951) (997)[Ni(L4)2] Black 6221 309 461 930 921 14[Ni(C16H10O2NS)2] (82) (6206) (323) (452) (1034) (949)[Zn(L1)2]sdotH2O Orange 6291 352 462 1058 15[Zn(C16H10O3N)2]sdotH2O (88) (6280) (360) (458) (1070)[Zn(L2)2] Yellow 6279 315 425 995 11[Zn(C17H10O4N)2] (61) (6283) (308) (431) (1007)[Zn(L3)2] Brick red 6021 325 935 1051 18[Zn(C15H9O3N2)2] (87) (6046) (302) (940) (1098)[Zn(L4)2]sdotH2O Yellow 6022 335 421 1001 1031 20[Zn(C16H10O2NS)2]sdotH2O (73) (5968) (341) (435) (993) (1046)

Table 2 IR spectral data of ligands and their metal complexes (cmminus1)

Compound ](OH) ](C=O) (120574 pyrone) ](C=N) ](CO) (carboxylate) ](CndashS) ](MndashN) ](MndashO)HL1 3241 1643 1605HL2 1651 1605 1365HL3 3246 1647 1591HL4 1622 1597 790[Ni(L1)2] 1619 1563 467 586[Ni(L2)2]sdotH2O 1618 1570 1318 419 514[Ni(L3)2]sdotH2O 1615 1563 480 500[Ni(L4)2] 1598 1564 743 443 524[Zn(L1)2]sdotH2O 1614 1574 460 599[Zn(L2)2] 1615 1563 1347 480 500[Zn(L3)2] 1615 1563 488 521[Zn(L4)2]sdotH2O 1609 1581 751 441 505

120573 = 11671

∘ 120574 = 9001∘ and 119881 = 562 (A)3 [Ni(L2)2]sdotH2O

119886 = 824 A 119887 = 924 A 119888 = 732 A 120572 = 10412∘ 120573 = 12444∘120574 = 9804

∘ and 119881 = 557 (A)3 [Ni(L3)2]sdotH2O 119886 = 940 A

119887 = 920 A 119888 = 846 A 120572 = 9745∘ 120573 = 10738∘ 120574 = 9145∘and 119881 = 731 (A)3 [Ni(L

4)2] 119886 = 773 A 119887 = 824 A

119888 = 849 A 120572 = 9830∘ 120573 = 10476∘ 120574 = 9055∘ and119881 = 540 (A)3 [Zn(L

1)2]sdotH2O 119886 = 960 A 119887 = 994 A

119888 = 889 A 120572 = 10234∘ 120573 = 10969∘ 120574 = 9394∘ and119881 = 848 (A)3 [Zn(L

3)2] 119886 = 876 A 119887 = 904 A 119888 = 861 A

120572 = 10578

∘ 120573 = 10302∘ 120574 = 9021∘ and 119881 = 682 (A)3The average crystallite sizes (119863) of the metal complexes arecalculated from the Scherrer formula [41]

119863 =

09120582

120573 cos 120579 (3)

where 120582 is the X-ray wavelength 120573 is the full width at halfmaximum of prominent intensity peak and 120579 is the diffrac-tion angle The [Ni(L

1)2] [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Ni(L4)2] [Zn(L

1)2]sdotH2O and [Zn(L

3)2] complexes have an

average crystallite size of 70 17 16 27 42 and 53 nm respec-tively suggesting that the complexes are in nanocrystallinephase

The SEM (Scanning Electron Microscope) is used toevaluate the morphology and particle size of the compoundsThe SEM photographs of [Ni(L

3)2]sdotH2O and [Ni(L

4)2] are

shown in Figure 6 The SEM micrographs show the agglom-erate particles of the complexes In case of [Ni(L

3)2]sdotH2O

and [Ni(L4)2] complexes some agglomerates appear to have

tiny needles while the other agglomerates appear to be ofspherical plates like morphologies

6 Bioinorganic Chemistry and Applications

Table 3 Electronic magnetic and ligand field parameters of Ni(II) complexes

Compound Absorption maxima(cmminus1) Tentative assignments Magnetic moment

(BM)]2]1

10Dq(cmminus1)

B(cmminus1)

120573

LFSE(kJsdotmolminus1)

[Ni(L1)2]85321520024900

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

312 178 8532 966 092 12250

[Ni( L2)2]sdotH2O87871600024390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

318 182 8787 935 089 12619

[Ni(L3)2]sdotH2O8313147052083324390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

325 176 8313 943 090 11940

[Ni(L4)2]86281631324570

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

291 189 8628 999 095 12392

Table 4 Thermal analysis results of metal complexes

Compound Temperature (∘C) Found (cald) Assignment

[Ni(L1)2][Ni(C16H10O3N)2]

180ndash420 1938 (1836) C6H4ON

421ndash718 6855 (6902) C26H16O5N

gt718 1207 (1262) NiO

[Ni(L2)2]sdotH2O[Ni(C17H10O4N)2]sdotH2O

30ndash90 283 (272) H2O335ndash478 6071 (6205) C24H14O5N2

479ndash849 2393 (2361) C10H6O2

gt849 1253 (1162) NiO

[Ni(L3)2]sdotH2O[Ni(C15H9O3N2)2]sdotH2O

30ndash65 309 (296) H2O180ndash879 8340 (8473) C30H18O5N4

gt880 1351 (1231) NiO

[Ni(L4)2][Ni(C16H10O2NS)2]

171ndash410 4591 (4525) C16H10O2NS411ndash670 4214 (4267) C16H10ONSgt670 1195 (1207) NiO

[Zn(L1)2]sdotH2O[Zn(C16H10O3N)2]sdotH2O

30ndash135 245 (295) H2O194ndash422 2495 (2592) C10H6O2

423ndash790 5948 (5809) C22H14O3N2

gt791 1312 (1304) ZnO

[Zn(L2)2][Zn(C17H10O4N)2]

195ndash265 1555 (1601) C7H4O266ndash661 6976 (7146) C27H16O4N2

gt662 1469 (1253) ZnO

[Zn(L3)2][Zn(C15H9O3N2)2]

157ndash192 1091 (1293) C5H3N193ndash485 2865 (2922) C10H6O2N486ndash835 4603 (4418) C15H9O3N2

gt836 1441 (1367) ZnO

[Zn(L4)2]sdotH2O[Zn(C16H10O2NS)2]sdotH2O

30ndash124 241 (279) H2O165ndash348 2741 (2673) C10H6O2N389ndash632 5698 (5784) C22H14ONS2gt632 1320 (1264) ZnO

Bioinorganic Chemistry and Applications 7

Table 5 Observed and calculated powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L1)2]sdotH2O

(a)

S number 2120579

Δ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1057 1057 0 83627 83627 0 1 02 1129 1129 0 78314 78314 1 0 03 1344 1344 0 65805 65805 0 0 14 1479 1479 0 59847 59847 minus1 1 05 1575 1575 0 56205 56205 minus1 minus1 16 1779 1779 0 49805 49805 minus1 1 17 1885 1868 0164 47046 47455 0 1 18 2116 2122 minus006 41962 41845 1 0 19 2214 2206 0074 40121 40255 1 minus1 110 2405 2407 minus0013 36968 36948 minus1 0 211 2504 2499 0054 35533 35608 1 2 012 2633 2635 minus0017 3382 33799 minus1 2 113 281 2804 0061 31731 31799 minus1 1 214 3265 3265 0 27404 27405 2 2 015 3506 3507 minus0012 25575 25566 minus3 1 016 3892 3886 0054 23124 23155 minus2 3 117 4389 4395 minus0058 20612 20586 minus1 3 218 4513 4516 minus0033 20076 20062 minus2 minus3 3

(b)

S number 2120579 valuesΔ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1258 1258 0 70315 70315 1 1 02 1381 1381 0 64077 64077 minus1 0 13 1573 1573 0 56299 56299 1 0 14 1735 1735 0 51064 51064 minus1 1 15 2075 2077 minus0017 42777 42742 minus1 3 06 2409 2413 minus0031 36907 36859 minus1 minus3 27 2532 2531 0012 35141 35158 2 2 08 2793 2797 minus0038 31916 31873 minus1 minus4 29 3015 3016 minus0008 29620 29612 0 minus3 310 3192 3190 0021 28015 28033 2 minus5 211 3443 3445 minus0017 26028 26016 minus1 5 012 3605 3606 minus0008 24892 24886 minus1 0 313 4275 4283 minus0081 21137 21099 3 1 2

36 Fluorescence Spectra The fluorescence characteristics ofmetal complexes were studied at room temperature in solidstate In metal complexes metal to ligand coordination maylead to significant changes of the fluorescence properties ofthe ligand including increase or decrease of the intensityemission wavelength shift quenching of the fluorescence orappearance of new emissions [42] The fluorescence spectraof HL

1ligand and its metal (Ni(II) and Zn(II)) complexes

were depicted in Figure 7 The Ni(II) and Zn(II) complexesof HL

1were characterised by emission bands around (522

569) nm and (458 644) nm upon photo excitation at 453and 357 nm respectively The Ni(II) complex of HL

2exhibits

emission bands at 449 and 524 nm Zn(II) complex of HL2

does not show any emission spectra The Ni(II) and Zn(II)complexes of HL

3were characterised by an emission bands

at (504 570 and 668) and 419 nm respectively The Ni(II)and Zn(II) complexes of HL

4exhibit emission bands around

539 and 613 nm respectively From the results red shift andquenching of the metal ions was observed in the case ofligands and its metal complexes

37 Antimicrobial Activity Theminimum inhibitory concen-trations (MIC) of the complexes compared with the ligandsand standard drugs are listed in Table 6 The results indicatethat themetal complexes displayedmore antibacterial activitycompared to the parent ligands under similar experimental

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

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CatalystsJournal of

Page 5: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Bioinorganic Chemistry and Applications 5

Table 1 Elemental analysis and physical properties of metal complexes

Molecular formulaColour( yield)

found(cald) Molar conductivity

(Ohmminus1 cm2 molminus1)C H N S M(NiZn)

[Ni(L1)2] Brick red 6449 321 423 991 10[Ni(C16H10O3N)2] (71) (6545) (340) (477) (1000)[Ni(L2)2]sdotH2O Light green 6159 302 421 879 12[Ni(C17H10O4N)2]sdotH2O (62) (6175) (332) (424) (888)[Ni(L3)2]sdotH2O Brick red 6107 323 923 943 15[Ni(C15H9O3N2)2]sdotH2O (85) (6115) (339) (951) (997)[Ni(L4)2] Black 6221 309 461 930 921 14[Ni(C16H10O2NS)2] (82) (6206) (323) (452) (1034) (949)[Zn(L1)2]sdotH2O Orange 6291 352 462 1058 15[Zn(C16H10O3N)2]sdotH2O (88) (6280) (360) (458) (1070)[Zn(L2)2] Yellow 6279 315 425 995 11[Zn(C17H10O4N)2] (61) (6283) (308) (431) (1007)[Zn(L3)2] Brick red 6021 325 935 1051 18[Zn(C15H9O3N2)2] (87) (6046) (302) (940) (1098)[Zn(L4)2]sdotH2O Yellow 6022 335 421 1001 1031 20[Zn(C16H10O2NS)2]sdotH2O (73) (5968) (341) (435) (993) (1046)

Table 2 IR spectral data of ligands and their metal complexes (cmminus1)

Compound ](OH) ](C=O) (120574 pyrone) ](C=N) ](CO) (carboxylate) ](CndashS) ](MndashN) ](MndashO)HL1 3241 1643 1605HL2 1651 1605 1365HL3 3246 1647 1591HL4 1622 1597 790[Ni(L1)2] 1619 1563 467 586[Ni(L2)2]sdotH2O 1618 1570 1318 419 514[Ni(L3)2]sdotH2O 1615 1563 480 500[Ni(L4)2] 1598 1564 743 443 524[Zn(L1)2]sdotH2O 1614 1574 460 599[Zn(L2)2] 1615 1563 1347 480 500[Zn(L3)2] 1615 1563 488 521[Zn(L4)2]sdotH2O 1609 1581 751 441 505

120573 = 11671

∘ 120574 = 9001∘ and 119881 = 562 (A)3 [Ni(L2)2]sdotH2O

119886 = 824 A 119887 = 924 A 119888 = 732 A 120572 = 10412∘ 120573 = 12444∘120574 = 9804

∘ and 119881 = 557 (A)3 [Ni(L3)2]sdotH2O 119886 = 940 A

119887 = 920 A 119888 = 846 A 120572 = 9745∘ 120573 = 10738∘ 120574 = 9145∘and 119881 = 731 (A)3 [Ni(L

4)2] 119886 = 773 A 119887 = 824 A

119888 = 849 A 120572 = 9830∘ 120573 = 10476∘ 120574 = 9055∘ and119881 = 540 (A)3 [Zn(L

1)2]sdotH2O 119886 = 960 A 119887 = 994 A

119888 = 889 A 120572 = 10234∘ 120573 = 10969∘ 120574 = 9394∘ and119881 = 848 (A)3 [Zn(L

3)2] 119886 = 876 A 119887 = 904 A 119888 = 861 A

120572 = 10578

∘ 120573 = 10302∘ 120574 = 9021∘ and 119881 = 682 (A)3The average crystallite sizes (119863) of the metal complexes arecalculated from the Scherrer formula [41]

119863 =

09120582

120573 cos 120579 (3)

where 120582 is the X-ray wavelength 120573 is the full width at halfmaximum of prominent intensity peak and 120579 is the diffrac-tion angle The [Ni(L

1)2] [Ni(L

2)2]sdotH2O [Ni(L

3)2]sdotH2O

[Ni(L4)2] [Zn(L

1)2]sdotH2O and [Zn(L

3)2] complexes have an

average crystallite size of 70 17 16 27 42 and 53 nm respec-tively suggesting that the complexes are in nanocrystallinephase

The SEM (Scanning Electron Microscope) is used toevaluate the morphology and particle size of the compoundsThe SEM photographs of [Ni(L

3)2]sdotH2O and [Ni(L

4)2] are

shown in Figure 6 The SEM micrographs show the agglom-erate particles of the complexes In case of [Ni(L

3)2]sdotH2O

and [Ni(L4)2] complexes some agglomerates appear to have

tiny needles while the other agglomerates appear to be ofspherical plates like morphologies

6 Bioinorganic Chemistry and Applications

Table 3 Electronic magnetic and ligand field parameters of Ni(II) complexes

Compound Absorption maxima(cmminus1) Tentative assignments Magnetic moment

(BM)]2]1

10Dq(cmminus1)

B(cmminus1)

120573

LFSE(kJsdotmolminus1)

[Ni(L1)2]85321520024900

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

312 178 8532 966 092 12250

[Ni( L2)2]sdotH2O87871600024390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

318 182 8787 935 089 12619

[Ni(L3)2]sdotH2O8313147052083324390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

325 176 8313 943 090 11940

[Ni(L4)2]86281631324570

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

291 189 8628 999 095 12392

Table 4 Thermal analysis results of metal complexes

Compound Temperature (∘C) Found (cald) Assignment

[Ni(L1)2][Ni(C16H10O3N)2]

180ndash420 1938 (1836) C6H4ON

421ndash718 6855 (6902) C26H16O5N

gt718 1207 (1262) NiO

[Ni(L2)2]sdotH2O[Ni(C17H10O4N)2]sdotH2O

30ndash90 283 (272) H2O335ndash478 6071 (6205) C24H14O5N2

479ndash849 2393 (2361) C10H6O2

gt849 1253 (1162) NiO

[Ni(L3)2]sdotH2O[Ni(C15H9O3N2)2]sdotH2O

30ndash65 309 (296) H2O180ndash879 8340 (8473) C30H18O5N4

gt880 1351 (1231) NiO

[Ni(L4)2][Ni(C16H10O2NS)2]

171ndash410 4591 (4525) C16H10O2NS411ndash670 4214 (4267) C16H10ONSgt670 1195 (1207) NiO

[Zn(L1)2]sdotH2O[Zn(C16H10O3N)2]sdotH2O

30ndash135 245 (295) H2O194ndash422 2495 (2592) C10H6O2

423ndash790 5948 (5809) C22H14O3N2

gt791 1312 (1304) ZnO

[Zn(L2)2][Zn(C17H10O4N)2]

195ndash265 1555 (1601) C7H4O266ndash661 6976 (7146) C27H16O4N2

gt662 1469 (1253) ZnO

[Zn(L3)2][Zn(C15H9O3N2)2]

157ndash192 1091 (1293) C5H3N193ndash485 2865 (2922) C10H6O2N486ndash835 4603 (4418) C15H9O3N2

gt836 1441 (1367) ZnO

[Zn(L4)2]sdotH2O[Zn(C16H10O2NS)2]sdotH2O

30ndash124 241 (279) H2O165ndash348 2741 (2673) C10H6O2N389ndash632 5698 (5784) C22H14ONS2gt632 1320 (1264) ZnO

Bioinorganic Chemistry and Applications 7

Table 5 Observed and calculated powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L1)2]sdotH2O

(a)

S number 2120579

Δ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1057 1057 0 83627 83627 0 1 02 1129 1129 0 78314 78314 1 0 03 1344 1344 0 65805 65805 0 0 14 1479 1479 0 59847 59847 minus1 1 05 1575 1575 0 56205 56205 minus1 minus1 16 1779 1779 0 49805 49805 minus1 1 17 1885 1868 0164 47046 47455 0 1 18 2116 2122 minus006 41962 41845 1 0 19 2214 2206 0074 40121 40255 1 minus1 110 2405 2407 minus0013 36968 36948 minus1 0 211 2504 2499 0054 35533 35608 1 2 012 2633 2635 minus0017 3382 33799 minus1 2 113 281 2804 0061 31731 31799 minus1 1 214 3265 3265 0 27404 27405 2 2 015 3506 3507 minus0012 25575 25566 minus3 1 016 3892 3886 0054 23124 23155 minus2 3 117 4389 4395 minus0058 20612 20586 minus1 3 218 4513 4516 minus0033 20076 20062 minus2 minus3 3

(b)

S number 2120579 valuesΔ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1258 1258 0 70315 70315 1 1 02 1381 1381 0 64077 64077 minus1 0 13 1573 1573 0 56299 56299 1 0 14 1735 1735 0 51064 51064 minus1 1 15 2075 2077 minus0017 42777 42742 minus1 3 06 2409 2413 minus0031 36907 36859 minus1 minus3 27 2532 2531 0012 35141 35158 2 2 08 2793 2797 minus0038 31916 31873 minus1 minus4 29 3015 3016 minus0008 29620 29612 0 minus3 310 3192 3190 0021 28015 28033 2 minus5 211 3443 3445 minus0017 26028 26016 minus1 5 012 3605 3606 minus0008 24892 24886 minus1 0 313 4275 4283 minus0081 21137 21099 3 1 2

36 Fluorescence Spectra The fluorescence characteristics ofmetal complexes were studied at room temperature in solidstate In metal complexes metal to ligand coordination maylead to significant changes of the fluorescence properties ofthe ligand including increase or decrease of the intensityemission wavelength shift quenching of the fluorescence orappearance of new emissions [42] The fluorescence spectraof HL

1ligand and its metal (Ni(II) and Zn(II)) complexes

were depicted in Figure 7 The Ni(II) and Zn(II) complexesof HL

1were characterised by emission bands around (522

569) nm and (458 644) nm upon photo excitation at 453and 357 nm respectively The Ni(II) complex of HL

2exhibits

emission bands at 449 and 524 nm Zn(II) complex of HL2

does not show any emission spectra The Ni(II) and Zn(II)complexes of HL

3were characterised by an emission bands

at (504 570 and 668) and 419 nm respectively The Ni(II)and Zn(II) complexes of HL

4exhibit emission bands around

539 and 613 nm respectively From the results red shift andquenching of the metal ions was observed in the case ofligands and its metal complexes

37 Antimicrobial Activity Theminimum inhibitory concen-trations (MIC) of the complexes compared with the ligandsand standard drugs are listed in Table 6 The results indicatethat themetal complexes displayedmore antibacterial activitycompared to the parent ligands under similar experimental

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 6: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

6 Bioinorganic Chemistry and Applications

Table 3 Electronic magnetic and ligand field parameters of Ni(II) complexes

Compound Absorption maxima(cmminus1) Tentative assignments Magnetic moment

(BM)]2]1

10Dq(cmminus1)

B(cmminus1)

120573

LFSE(kJsdotmolminus1)

[Ni(L1)2]85321520024900

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

312 178 8532 966 092 12250

[Ni( L2)2]sdotH2O87871600024390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

318 182 8787 935 089 12619

[Ni(L3)2]sdotH2O8313147052083324390

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

325 176 8313 943 090 11940

[Ni(L4)2]86281631324570

3A2g(F) rarr3T2g(F) (]1)

3A2g(F) rarr3T1g(F) (]2)

3A2g(F) rarr3T1g(P) (]3)

291 189 8628 999 095 12392

Table 4 Thermal analysis results of metal complexes

Compound Temperature (∘C) Found (cald) Assignment

[Ni(L1)2][Ni(C16H10O3N)2]

180ndash420 1938 (1836) C6H4ON

421ndash718 6855 (6902) C26H16O5N

gt718 1207 (1262) NiO

[Ni(L2)2]sdotH2O[Ni(C17H10O4N)2]sdotH2O

30ndash90 283 (272) H2O335ndash478 6071 (6205) C24H14O5N2

479ndash849 2393 (2361) C10H6O2

gt849 1253 (1162) NiO

[Ni(L3)2]sdotH2O[Ni(C15H9O3N2)2]sdotH2O

30ndash65 309 (296) H2O180ndash879 8340 (8473) C30H18O5N4

gt880 1351 (1231) NiO

[Ni(L4)2][Ni(C16H10O2NS)2]

171ndash410 4591 (4525) C16H10O2NS411ndash670 4214 (4267) C16H10ONSgt670 1195 (1207) NiO

[Zn(L1)2]sdotH2O[Zn(C16H10O3N)2]sdotH2O

30ndash135 245 (295) H2O194ndash422 2495 (2592) C10H6O2

423ndash790 5948 (5809) C22H14O3N2

gt791 1312 (1304) ZnO

[Zn(L2)2][Zn(C17H10O4N)2]

195ndash265 1555 (1601) C7H4O266ndash661 6976 (7146) C27H16O4N2

gt662 1469 (1253) ZnO

[Zn(L3)2][Zn(C15H9O3N2)2]

157ndash192 1091 (1293) C5H3N193ndash485 2865 (2922) C10H6O2N486ndash835 4603 (4418) C15H9O3N2

gt836 1441 (1367) ZnO

[Zn(L4)2]sdotH2O[Zn(C16H10O2NS)2]sdotH2O

30ndash124 241 (279) H2O165ndash348 2741 (2673) C10H6O2N389ndash632 5698 (5784) C22H14ONS2gt632 1320 (1264) ZnO

Bioinorganic Chemistry and Applications 7

Table 5 Observed and calculated powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L1)2]sdotH2O

(a)

S number 2120579

Δ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1057 1057 0 83627 83627 0 1 02 1129 1129 0 78314 78314 1 0 03 1344 1344 0 65805 65805 0 0 14 1479 1479 0 59847 59847 minus1 1 05 1575 1575 0 56205 56205 minus1 minus1 16 1779 1779 0 49805 49805 minus1 1 17 1885 1868 0164 47046 47455 0 1 18 2116 2122 minus006 41962 41845 1 0 19 2214 2206 0074 40121 40255 1 minus1 110 2405 2407 minus0013 36968 36948 minus1 0 211 2504 2499 0054 35533 35608 1 2 012 2633 2635 minus0017 3382 33799 minus1 2 113 281 2804 0061 31731 31799 minus1 1 214 3265 3265 0 27404 27405 2 2 015 3506 3507 minus0012 25575 25566 minus3 1 016 3892 3886 0054 23124 23155 minus2 3 117 4389 4395 minus0058 20612 20586 minus1 3 218 4513 4516 minus0033 20076 20062 minus2 minus3 3

(b)

S number 2120579 valuesΔ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1258 1258 0 70315 70315 1 1 02 1381 1381 0 64077 64077 minus1 0 13 1573 1573 0 56299 56299 1 0 14 1735 1735 0 51064 51064 minus1 1 15 2075 2077 minus0017 42777 42742 minus1 3 06 2409 2413 minus0031 36907 36859 minus1 minus3 27 2532 2531 0012 35141 35158 2 2 08 2793 2797 minus0038 31916 31873 minus1 minus4 29 3015 3016 minus0008 29620 29612 0 minus3 310 3192 3190 0021 28015 28033 2 minus5 211 3443 3445 minus0017 26028 26016 minus1 5 012 3605 3606 minus0008 24892 24886 minus1 0 313 4275 4283 minus0081 21137 21099 3 1 2

36 Fluorescence Spectra The fluorescence characteristics ofmetal complexes were studied at room temperature in solidstate In metal complexes metal to ligand coordination maylead to significant changes of the fluorescence properties ofthe ligand including increase or decrease of the intensityemission wavelength shift quenching of the fluorescence orappearance of new emissions [42] The fluorescence spectraof HL

1ligand and its metal (Ni(II) and Zn(II)) complexes

were depicted in Figure 7 The Ni(II) and Zn(II) complexesof HL

1were characterised by emission bands around (522

569) nm and (458 644) nm upon photo excitation at 453and 357 nm respectively The Ni(II) complex of HL

2exhibits

emission bands at 449 and 524 nm Zn(II) complex of HL2

does not show any emission spectra The Ni(II) and Zn(II)complexes of HL

3were characterised by an emission bands

at (504 570 and 668) and 419 nm respectively The Ni(II)and Zn(II) complexes of HL

4exhibit emission bands around

539 and 613 nm respectively From the results red shift andquenching of the metal ions was observed in the case ofligands and its metal complexes

37 Antimicrobial Activity Theminimum inhibitory concen-trations (MIC) of the complexes compared with the ligandsand standard drugs are listed in Table 6 The results indicatethat themetal complexes displayedmore antibacterial activitycompared to the parent ligands under similar experimental

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 7: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Bioinorganic Chemistry and Applications 7

Table 5 Observed and calculated powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L1)2]sdotH2O

(a)

S number 2120579

Δ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1057 1057 0 83627 83627 0 1 02 1129 1129 0 78314 78314 1 0 03 1344 1344 0 65805 65805 0 0 14 1479 1479 0 59847 59847 minus1 1 05 1575 1575 0 56205 56205 minus1 minus1 16 1779 1779 0 49805 49805 minus1 1 17 1885 1868 0164 47046 47455 0 1 18 2116 2122 minus006 41962 41845 1 0 19 2214 2206 0074 40121 40255 1 minus1 110 2405 2407 minus0013 36968 36948 minus1 0 211 2504 2499 0054 35533 35608 1 2 012 2633 2635 minus0017 3382 33799 minus1 2 113 281 2804 0061 31731 31799 minus1 1 214 3265 3265 0 27404 27405 2 2 015 3506 3507 minus0012 25575 25566 minus3 1 016 3892 3886 0054 23124 23155 minus2 3 117 4389 4395 minus0058 20612 20586 minus1 3 218 4513 4516 minus0033 20076 20062 minus2 minus3 3

(b)

S number 2120579 valuesΔ2120579

119889-spacingℎ 119896 119897

Observed Calculated Observed Calculated1 1258 1258 0 70315 70315 1 1 02 1381 1381 0 64077 64077 minus1 0 13 1573 1573 0 56299 56299 1 0 14 1735 1735 0 51064 51064 minus1 1 15 2075 2077 minus0017 42777 42742 minus1 3 06 2409 2413 minus0031 36907 36859 minus1 minus3 27 2532 2531 0012 35141 35158 2 2 08 2793 2797 minus0038 31916 31873 minus1 minus4 29 3015 3016 minus0008 29620 29612 0 minus3 310 3192 3190 0021 28015 28033 2 minus5 211 3443 3445 minus0017 26028 26016 minus1 5 012 3605 3606 minus0008 24892 24886 minus1 0 313 4275 4283 minus0081 21137 21099 3 1 2

36 Fluorescence Spectra The fluorescence characteristics ofmetal complexes were studied at room temperature in solidstate In metal complexes metal to ligand coordination maylead to significant changes of the fluorescence properties ofthe ligand including increase or decrease of the intensityemission wavelength shift quenching of the fluorescence orappearance of new emissions [42] The fluorescence spectraof HL

1ligand and its metal (Ni(II) and Zn(II)) complexes

were depicted in Figure 7 The Ni(II) and Zn(II) complexesof HL

1were characterised by emission bands around (522

569) nm and (458 644) nm upon photo excitation at 453and 357 nm respectively The Ni(II) complex of HL

2exhibits

emission bands at 449 and 524 nm Zn(II) complex of HL2

does not show any emission spectra The Ni(II) and Zn(II)complexes of HL

3were characterised by an emission bands

at (504 570 and 668) and 419 nm respectively The Ni(II)and Zn(II) complexes of HL

4exhibit emission bands around

539 and 613 nm respectively From the results red shift andquenching of the metal ions was observed in the case ofligands and its metal complexes

37 Antimicrobial Activity Theminimum inhibitory concen-trations (MIC) of the complexes compared with the ligandsand standard drugs are listed in Table 6 The results indicatethat themetal complexes displayedmore antibacterial activitycompared to the parent ligands under similar experimental

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 8: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

8 Bioinorganic Chemistry and Applications

Table 6 MIC values of antimicrobial activity of ligands and their metal complexes (120583gmL)

Compound Bacillus subtilis Staphylococcus aureus Proteus vulgaris Klebsiella pneumoniae Candida albicansHL1 mdash mdash mdash mdash mdashHL2 80 80 80 80 80HL3 mdash mdash mdash mdash mdashHL4 mdash mdash mdash mdash mdash[Ni(L1)2] 35 40 32 41 75[Ni(L2)2]sdotH2O 70 80 65 85 mdash[Ni(L3)2]sdotH2O 45 45 50 33 33[Ni(L4)2] 75 80 mdash 78 mdash[Zn(L1)2]sdotH2O mdash mdash mdash mdash mdash[Zn(L2)2] 85 78 80 75 80[Zn(L3)2] 30 30 33 30 33[Zn(L4)2]sdotH2O mdash 80 mdash 80 mdashKanamycin 4 10 8 11 mdashClotrimazole mdash mdash mdash mdash 10

400 500 600 700 800 900 1000 1100 1200

010

011

012

Abso

rban

ce

Wavelength (nm)

(a)

300 400 500 600 700 800

Abso

rban

ce

Wavelength (nm)

00

02

04

06

08

10

(b)

Figure 2 Electronic spectra of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

100 200 300 400 500 600 700 800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(a)

100 200 300 400 500 600 700 900800100

50

0

Temperature (∘C)

Wei

ght (

)

00

02

04

DTG

(∘

C)

(b)

Figure 3 TG-DTG graph of (a) [Ni(L4)2] and (b) [Zn(L

4)2]sdotH2O

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 9: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Bioinorganic Chemistry and Applications 9

O

O HC N

A

X

M

O

OCH

N

A

X

middot nH2O

A = C and X = OSCOOA = N and X = OM = Ni(II)Zn(II)

Figure 4 Proposed structure of the metal complexes

conditions on same microorganisms except [Ni(L2)2]sdotH2O

and [Zn(L1)2]sdotH2O complexes The results indicate that

the metal complexes displayed more antibacterial activitycompared to the parent ligands under similar experimentalconditions on same microorganisms except [Zn(L

1)2]sdotH2O

However [Ni(L1)2] [Ni(L

3)2]sdotH2O [Zn(L

2)2] and [Zn(L

3)2]

complexes showed antifungal activity while the remainingcomplexes did not show any activity However [Ni(L

1)2]

[Ni(L3)2]sdotH2O and [Zn(L

3)2] complexes showed antifungal

activity while the remaining complexes did not show anyactivity Among all the metal complexes [Zn(L

3)2] complex

showed good activity against all bacteria and fungi strainsIncrease in the activity of the complexes compared to that ofligands can be explained on the basis of Overtonersquos conceptand Tweedyrsquos chelation theory The theory states that thepolarity of the metal ion is reduced on complexation dueto the partial sharing of its positive charge with donorgroups Consequently the positive charge is delocalized overthe whole ring which causes the improved lipophilicityof the compound through cell membrane of the pathogen[43] The negative results can be attributed either to theinability of the complexes to diffuse into the bacteria cellmembrane and hence they become unable to interfere with itsbiological activity or they can diffuse and become inactivatedby unknown cellular mechanism that is bacterial enzymes[44]

38 Nematicidal Activity All complexes except [Ni(L3)2]sdot

H2O and [Zn(L

3)2] showed very less nematicidal activity

against Meloidogyne incognita However [Ni(L3)2]sdotH2O and

[Zn(L3)2] complexes exhibited moderate activity indicating

47 and 51 mortality respectively after 48 h exposurein 250120583gmL concentration However the activity of themetal complexes depends on concentration and time that isactivity was higher at high concentrations and increased withtime

39 DPPH Radical Scavenging Activity The antioxidantactivity of the complexes was tested by measuring theirability to donate an electron to the free radical compound

Table 7 IC50 values (120583gmL) of DPPH radical scavenging activityof ligands and their metal complexes

Compound IC50 (120583gmL)HL3 127HL4 040[Ni(L1)2] 121[Ni(L4)2] 109[Zn(L4)2]sdotH2O 069BHT 067

Table 8 IC50 values (120583gmL) of cytotoxic activity of ligands andtheir metal complexes

Compound Raw MCF-7 COLO 205HL1 468 245 201HL2 561 342 391HL3 528 292 152HL4 469 304 681[Ni(L1)2] 2248 671 546[Ni( L2)2]sdotH2O 363 265 609[Ni(L3)2]sdotH2O 530 369 714[Ni(L4)2] 586 356 499[Zn(L1)2]sdotH2O 440 401 547[Zn(L2)2] 340 523 439[Zn(L3)2] 331 226 420[Zn(L4)2]sdotH2O 425 392 535Cis-platin 15 17 56

DPPH monitoring changes in absorption at 517 nm usingUV-VIS spectrophotometer IC

50values were calculated and

compared with the standard IC50

values of the metal com-plexes are tabulated in Table 7 All complexes showed veryless activity except [Ni(L

1)2] [Ni(L

4)2] and [Zn(L

4)2]sdotH2O

complexes Among all the complexes [Zn(L4)2]sdotH2O (IC

50=

069 120583gmL) complex exhibited comparable activity to thatof standard drug BHT (butylated hydroxyl toluene) (IC

50=

067 120583gmL)

310 Cytotoxic Activity Thecytotoxicity of Schiff base ligandsand their metal complexes were carried out using MTTassay IC

50is employed to stand for the cytotoxicities of the

compounds against the cancer cell lines the smaller the IC50

value in the same condition is the higher the cell growthinhibitory potency DMSO when used as control withouttest sample it does not exhibit any cytotoxic activity againstall cancer cell lines Cis-platin is used as positive controland it showed the highest cytotoxicity The IC

50values were

calculated after 48 h of incubation with compounds andare listed in Table 8 As shown in Table 8 all the ligandsand their metal complexes showed lower cytotoxicity againstselected cancer cell lines compared to the cis-platin HL

3

ligand showed enhanced activity against COLO 205 celllines compared to all ligands and metal complexes (IC

50=

152 120583gmL)The lowest IC50values (331 and 226120583gmL) are

observed for Zn(II) complex of HL3ligand against raw and

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 10: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

10 Bioinorganic Chemistry and Applications

10 20 30 40 50 60 70 80

0

20

40

60

80

100

Num

ber o

f cou

nts

2120579 (deg)

(a)

Num

ber o

f cou

nts

10 20 30 40 50

2120579 (deg)

200

400

600

800

1000

(b)

Figure 5 Powder XRD patterns of (a) [Ni(L1)2] (b) [Zn(L

1)2]sdotH2O

(a) (b)

Figure 6 SEM micrograph of (a) [Ni(L3)2]sdotH2O and (b) [Ni(L

4)2]

MCF-7 cell lines among all the ligands and metal complexesindicating its significant potency against two cancer cell linesThe results revealed that pyridine ring may be playing animportant role in the cytotoxicity of the compounds

311 DNA Cleavage Activity pUC19 DNA was chosen forthe DNA cleavage activity of the complexes The studieswere done using gel electrophoresis Its naturally occurringsupercoiled form (Form I) when nicked gives rise to an opencircular relaxed form (Form II) and upon further cleavageresults in the linear form (Form III) When subjected to gelelectrophoresis Form I migrates relatively faster while thenicked form (Form II) migrates slowly and linearized FormIII migrates between Form I and Form II [45] In the presentstudy gel electrophoresis experiments were performed inthe presence and absence of an oxidizing agent H

2O2to

investigate the mechanism of nucleolytic activity of the

complexes The activity was greater for the complexes inthe presence of H

2O2 Control (DNA alone) does not show

activity (Figure 8(a)) When FeSO4is used as standard it

shows complete DNA cleavage In the absence of H2O2all

complexes show partial nucleolytic activity Probably thismay be due to the redox behaviour of the metal ions Theseresults indicated the important role of the metal ions incleavage studies In the presence of H

2O2 (Figure 8(b))

absence of marker bands was observed in all the com-plexes except [Ni(L

3)2]sdotH2O and [Zn(L

3)2] [Zn(L

4)2]sdotH2O

complexes indicate the complete DNA cleavage activity Inthe case of [Ni(L

3)2]sdotH2O [Zn(L

3)2] and [Zn(L

4)2]sdotH2O

complexes a decrease in the intensity of bands was observedcompared to the control This is probably due to the partialcleavage of the DNA The DNA cleavage activity of thecomplexes in the presence of H

2O2may be due to the

reaction of hydroxy radicals with DNAThe general oxidative

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 11: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Bioinorganic Chemistry and Applications 11

(a)

(b)

(c)

500 600 700

Wavelength (nm)

0

50000

100000

150000

200000

250000

300000

350000

400000

Inte

nsity

(CPS

)

Figure 7 Fluorescence spectra of (a) HL1 (b) [Ni(L

1)2] and (c)

[Zn(L1)2]sdotH2O

(a)

(b)

Figure 8 Gel electrophoresis photograph of metal complexes(a) Gel electrophoresis photograph showing the effects of metalcomplexes on pUC 19DNA lane 1 DNA + [Ni(L

1)2] lane 2 DNA

+ [Ni(L2)2]sdotH2O lane 3 DNA + [Ni(L

3)2]sdotH2O lane 4 DNA +

[Ni(L4)2] lane 5 DNA + [Zn(L

1)2]sdotH2O lane 6 DNA + [Zn(L

2)2]

lane 7 DNA+ [Zn(L3)2] lane 8 DNA+ [Zn(L

4)2]sdotH2O lane 9 DNA

+ FeSO4 lane C DNA alone (b) Gel electrophoresis photograph

showing the effects of metal complexes on pUC 19DNA in thepresence of H

2O2 lane 1 DNA + [Ni(L

1)2] + H

2O2 lane 2 DNA +

[Ni(L2)2]sdotH2O + H

2O2 lane 3 DNA + [Ni(L

3)2]sdotH2O + H

2O2 lane

4 DNA + [Ni(L4)2] + H2O2 lane 5 DNA + [Zn(L

1)2]sdotH2O +H

2O2

lane 6 DNA + [Zn(L2)2] + H

2O2 lane 7 DNA + [Zn(L

3)2] + H

2O2

lane 8DNA+ [Zn(L4)2]sdotH2O+H

2O2 lane 9DNA+FeSO

4+H2O2

lane C2 DNA + H2O2 lane C1 DNA alone

mechanisms of the DNA cleavage studies were reportedby several research groups [46ndash48] Many literature reportsinfer that the compound was to cleave the DNA it can beconcluded that the compound inhibits the growth of thepathogenic organism by cleaving the genome [49]

4 Conclusions

Ni(II) and Zn(II) complexes have been synthesized using 3-formyl chromone Schiff bases and characterized by variousanalytical and spectral data Based on the electronic spectramagnetic moment and elemental analysis data octahedralgeometry was proposed for Ni(II) and Zn(II) complexesThe well-defined crystalline and homogeneous nature of themetal complexes is observed from powder XRD and SEManalyses The antimicrobial activity data has shown that[Zn(L

3)2] complex displayed higher activity among all other

metal complexes The nematicidal activity of metal com-plexes revealed that [Ni(L

3)2]sdotH2O and [Zn(L

3)2] complexes

showed moderate activity [Zn(L4)2]sdotH2O complex exhibited

greater antioxidant activity compared to the remaining metalcomplexes All metal complexes exhibited considerable cyto-toxic activity against Raw MCF-7 and COLO 205 cell linesThe DNA cleavage studies of metal complexes showed moreprominent activity in the presence of H

2O2compared to that

in the absence of H2O2

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors wish to thank Dr MRP Reddy CMET (Centrefor the Materials for Electronic Technologies) Hyderabadfor providing TG facility The authors are thankful to theDepartment of Biochemistry SV University Tirupathi forantioxidant activity study Vimta Labs Ltd Hyderabadfor DNA cleavage studies and PSG college of PharmacyCoimbatore Tamilnadu for anticancer activity studies Theauthors also wish to thank the Ministry of Human ResourceDevelopment for granting the research fellowship to KavithaPalakuri

References

[1] N K Singh A Srivastava A Sodhi and P Ranjan ldquoIn vitroand in vivo antitumour studies of a new thiosemicarbazidederivative and its complexes with 3d-metal ionsrdquo TransitionMetal Chemistry vol 25 no 2 pp 133ndash140 2000

[2] N Raman K Pothiraj and T Baskaran ldquoDNA interactionantimicrobial electrochemical and spectroscopic studies ofmetal(II) complexes with tridentate heterocyclic Schiff basederived from 21015840-methylacetoacetaniliderdquo Journal of MolecularStructure vol 1000 no 1ndash3 pp 135ndash144 2011

[3] C Yuan L Lu Y Wu et al ldquoSynthesis characterizationand protein tyrosine phosphatases inhibition activities of oxo-vanadium(IV) complexes with Schiff base and polypyridylderivativesrdquo Journal of Inorganic Biochemistry vol 104 no 9pp 978ndash986 2010

[4] Y Li Z-Y Yang and J-C Wu ldquoSynthesis crystal structuresbiological activities and fluorescence studies of transition metalcomplexes with 3-carbaldehyde chromone thiosemicarbazonerdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5692ndash5701 2010

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 12: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

12 Bioinorganic Chemistry and Applications

[5] Y S Shim K C Kim D Y Chi K-H Lee and H CholdquoFormylchromone derivatives as a novel class of proteintyrosine phosphatase 1B inhibitorsrdquo Bioorganic and MedicinalChemistry Letters vol 13 no 15 pp 2561ndash2563 2003

[6] K M Khan N Ambreen U R Mughal S Jalil S Perveenand M I Choudhary ldquo3-formylchromones potential antiin-flammatory agentsrdquo European Journal of Medicinal Chemistryvol 45 no 9 pp 4058ndash4064 2010

[7] G Mhaske P Nilkanth A Auti S Davange and S ShelkeldquoAqua medicated microwave assisted synthesis of Schiff basesand their biological evaluationrdquo International Journal of Innova-tive Research in Science Engineering and Technology vol 3 pp8156ndash8162 2014

[8] M T Hussain N H Rama and K M Khan ldquoA novelunusual isocoumarin derivative 3119867-Furo[3 4-119888] isochromene-1 5-dionerdquo Letters in Organic Chemistry vol 7 no 7 pp 557ndash560 2010

[9] A A Osowole ldquoSynthesis characterization in-vitro antibac-terial and anticancer studies on some metal(II) complexes of(methylsulfanyl)chromenol Schiff baserdquo Elixir Applied Chem-istry vol 39 pp 4827ndash4831 2011

[10] K M Khan A Ahmad N Ambreen et al ldquoSchiff bases of 3-formylchromones as antibacterial antifungal and phytotoxicagentsrdquo Letters in Drug Design and Discovery vol 6 no 5 pp363ndash373 2009

[11] S Bhatnagar S Sahi P Kackar et al ldquoSynthesis and dockingstudies on styryl chromones exhibiting cytotoxicity in humanbreast cancer cell linerdquo Bioorganic and Medicinal ChemistryLetters vol 20 no 16 pp 4945ndash4950 2010

[12] A Gomes O Neuwirth M Freitas et al ldquoSynthesis and antiox-idant properties of new chromone derivativesrdquo Bioorganic ampMedicinal Chemistry vol 17 no 20 pp 7218ndash7226 2009

[13] L Z Piao H R Park Y K Park S K Lee J H Park andM K Park ldquoMushroom tyrosinase inhibition activity of somechromonesrdquo Chemical and Pharmaceutical Bulletin vol 50 no3 pp 309ndash311 2002

[14] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoSynthesis characterization in vitro antimicrobial andDNA cleavage studies of Co(II) Ni(II) and Cu(II) complexeswith ONOOdonor coumarin Schiff basesrdquo Journal of MolecularStructure vol 985 no 2-3 pp 330ndash338 2011

[15] F Arjmand F Sayeed andMMuddassir ldquoSynthesis of new chi-ral heterocyclic Schiff basemodulatedCu(II)Zn(II) complexestheir comparative binding studies with CT-DNA mononu-cleotides and cleavage activityrdquo Journal of Photochemistry andPhotobiology B Biology vol 103 no 2 pp 166ndash179 2011

[16] C N Sudhamani H S B Naik T R R Naik and MC Prabhakara ldquoSynthesis DNA binding and cleavage stud-ies of Ni(II) complexes with fused aromatic N-containingligandsrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 72 no 3 pp 643ndash647 2009

[17] D-D Qin Z-Y Yang and B-D Wang ldquoSpectra and DNA-binding affinities of copper(II) nickel(II) complexes with anovel glycine Schiff base derived from chromonerdquo Spectrochim-ica Acta AMolecular and Biomolecular Spectroscopy vol 68 no3 pp 912ndash917 2007

[18] B-D Wang Z-Y Yang M-H Lu J Hai Q Wang and Z-N Chen ldquoSynthesis characterization cytotoxic activity andDNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazonerdquo Journal of OrganometallicChemistry vol 694 no 25 pp 4069ndash4075 2009

[19] Y Li Z Y Yang Z C Liao Z C Han and Z C LiuldquoSynthesis crystal structure DNA binding properties andantioxidant activities of transition metal complexes with 3-carbaldehyde-chromone semicarbazonerdquo Inorganic ChemistryCommunications vol 13 no 10 pp 1213ndash1216 2010

[20] B-D Wang Z-Y Yang and T-R Li ldquoSynthesis characteri-zation and DNA-binding properties of the Ln(III) complexeswith 6-hydroxy chromone-3-carbaldehyde-(21015840-hydroxy) ben-zoyl hydrazonerdquo Bioorganic and Medicinal Chemistry vol 14no 17 pp 6012ndash6021 2006

[21] P Kavitha M Saritha and K L Reddy ldquoSynthesis structuralcharacterization fluorescence antimicrobial antioxidant andDNA cleavage studies of Cu(II) complexes of formyl chromoneSchiff basesrdquo Spectrochimica Acta A Molecular and Biomolecu-lar Spectroscopy vol 102 pp 159ndash168 2013

[22] P Kavitha M R Chary B V A A Singavarapu and KL Reddy ldquoSynthesis characterization biological activity andDNA cleavage studies of tridentate Schiff bases and their Co(II)complexesrdquo Journal of Saudi Chemical Society 2013

[23] P Kavitha and K L Reddy ldquoPd(II) complexes bearingchromone based Schiff bases synthesis characterisation andbiological activity studiesrdquo Arabian Journal of Chemistry 2012

[24] A Nohara T Umetani and Y Sanno ldquoA facile synthesis ofchromone-3-carboxaldehyde chromone-3-carboxylic acid and3-hydroxymethylchromonerdquoTetrahedron Letters vol 14 no 22pp 1995ndash1998 1973

[25] I Sigg G Haas and T Winkler ldquoThe reaction of 3-formylchromone with ortho-substituted anilines Preparationof a Tetraaza [14] annulenerdquo Helevetica Chimica Acta vol 65no 1 pp 275ndash279 1982

[26] K M Khan N Ambreen S Hussain S Perveen and M IChoudhary ldquoSchiff bases of 3-formylchromone as thymidinephosphorylase inhibitorsrdquo Bioorganic andMedicinal Chemistryvol 17 no 8 pp 2983ndash2988 2009

[27] J E Stemper and J M Matsen ldquoDevice for turbidity stan-dardizing of cultures for antibiotic sensitivity testingrdquo AppliedMicrobiology vol 19 no 6 pp 1015ndash1016 1970

[28] K Shanker R Rohini V Ravinder P M Reddy and Y-P HoldquoRu(II) complexes of N

4and N

2O2macrocyclic Schiff base lig-

ands their antibacterial and antifungal studiesrdquo SpectrochimicaActa A Molecular and Biomolecular Spectroscopy vol 73 no 1pp 205ndash211 2009

[29] P C Trivedi Nematode Diseases in Plants CBS New DelhiIndia 1st edition 1998

[30] J Cayrol C Djian and L Pijarowski ldquoStudy of the nematicidalproperties of the culture filtrate of the nematophagous fungusPaecilomyces lilacinusrdquo Revue de Nematologie vol 12 pp 331ndash336 1989

[31] A Braca N de Tommasi L di Bari C Pizza M Politi andI Morelli ldquoAntioxidant principles from Bauhinia tarapotensisrdquoJournal of Natural Products vol 64 no 7 pp 892ndash895 2001

[32] S Sathiyaraj R J Butcher and Ch Jayabalakrishnan ldquoSynthe-sis characterization DNA interaction and in vitro cytotoxicityactivities of ruthenium(II) Schiff base complexesrdquo Journal ofMolecular Structure vol 1030 pp 95ndash103 2012

[33] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[34] A I Vogel A Text Book of Quantitative Inorganic AnalysisLongman 3rd edition 1961

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 13: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Bioinorganic Chemistry and Applications 13

[35] O A El-Gammal G A El-Reash and S F Ahmed ldquoStructuralspectral thermal and biological studies on 2-oxo-N1015840-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohy-drazide (H

2L) and its metal complexesrdquo Journal of Molecular

Structure vol 1007 pp 1ndash10 2012[36] C Anitha C D Sheela P Tharmaraj and S J Raja ldquoSynthesis

and characterization of VO(II) Co(II) Ni(II) Cu(II) andZn(II) complexes of chromone based azo-linked Schiff baseligandrdquo Spectrochimica Acta A Molecular and BiomolecularSpectroscopy vol 98 pp 35ndash42 2012

[37] M Padmaja J Pragathi and C G Kumari ldquoSynthesis spectralcharacterization molecular modeling and biological activity offirst row transition metal complexes with Schiff base ligandderived from chromone-3-carbaldehyde and o-amino benzoicacidrdquo Journal of Chemical and Pharmaceutical Research vol 3no 4 pp 602ndash613 2011

[38] B Kannamba K L Reddy and B V AppaRao ldquoRemovalof Cu(II) from aqueous solutions using chemically modifiedchitosanrdquo Journal of Hazardous Materials vol 175 no 1ndash3 pp939ndash948 2010

[39] S Chandra and L K Gupta ldquoSpectroscopic and biologicalstudies on newly synthesized nickel(II) complexes of semi-carbazones and thiosemicarbazonesrdquo Spectrochimica Acta AMolecular and Biomolecular Spectroscopy vol 62 no 4-5 pp1089ndash1094 2005

[40] P K Singh and D N Kumar ldquoSpectral studies on cobalt(II)nickel(II) and copper(II) complexes of naphthaldehyde substi-tuted aroylhydrazonesrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 64 no 4 pp 853ndash858 2006

[41] B E Warren X-Ray Diffraction Dover New York NY USA2nd edition 1990

[42] X Huang Y Xia H Zhang et al ldquoSynthesis crystal structureand fluorescence studies of (1-naphthyl)(pyridyl)urea metalcomplexesrdquo Inorganic Chemistry Communications vol 11 no 4pp 450ndash453 2008

[43] A K Sharma and S Chandra ldquoComplexation of nitrogen andsulphur donor Schiff rsquos base ligand to Cr(III) and Ni(II) metalions synthesis spectroscopic and antipathogenic studiesrdquo Spec-trochimica Acta A Molecular and Biomolecular Spectroscopyvol 78 no 1 pp 337ndash342 2011

[44] T A Yousef G M Abu El-Reash O A El-Gammal and RA Bedier ldquoCo(II) Cu(II) Cd(II) Fe(III) and U(VI) complexescontaining a NSNO donor ligand synthesis characterizationoptical band gap in vitro antimicrobial and DNA cleavagestudiesrdquo Journal of Molecular Structure vol 1029 pp 149ndash1602012

[45] H-L Seng H-K A Ong R N Z R A Rahman et al ldquoFactorsaffecting nucleolytic efficiency of some ternarymetal complexeswith DNA binding and recognition domains Crystal andmolecular structure of Zn(phen)(edda)rdquo Journal of InorganicBiochemistry vol 102 no 11 pp 1997ndash2011 2008

[46] S K Bharti S K Patel G Nath R Tilak and S K Singh ldquoSyn-thesis characterization DNA cleavage and in vitro antimicro-bial activities of copper(II) complexes of Schiff bases containinga 24-disubstituted thiazolerdquoTransitionMetal Chemistry vol 35no 8 pp 917ndash925 2010

[47] D S Sigman A Mazumder and D M Perrin ldquoChemicalnucleasesrdquoChemical Reviews vol 93 no 6 pp 2295ndash2316 1993

[48] T Kobayashi M Kunita S Nishino et al ldquoRelease of freenucleobases from oligomers by copper(II)-peroxide adductrdquoPolyhedron vol 19 no 26-27 pp 2639ndash2648 2000

[49] T A Yousef G M Abu El-Reash O A El-Gammal and R ABedier ldquoSynthesis characterization optical band gap in vitroantimicrobial activity and DNA cleavage studies of some metalcomplexes of pyridyl thiosemicarbazonerdquo Journal of MolecularStructure vol 1035 pp 307ndash317 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 14: Research Article Synthesis, Structural Characterization ...downloads.hindawi.com/journals/bca/2014/568741.pdf · Synthesis, Structural Characterization, and Biological Activity

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of