research article syntheses, spectral characterization, and...

Hindawi Publishing CorporationBioinorganic Chemistry and ApplicationsVolume 2013 Article ID 981764 10 pageshttpdxdoiorg1011552013981764

Research ArticleSyntheses Spectral Characterization and Antimicrobial Studieson the Coordination Compounds of Metal Ions with Schiff BaseContaining Both Aliphatic and Aromatic Hydrazide Moieties

Dinesh Kumar1 Silky Chadda1 Jyoti Sharma1 and Parveen Surain2

1 Department of Chemistry National Institute of Technology Kurukshetra Haryana 136119 India2Department of Microbiology Kurukshetra University Kurukshetra Haryana 136119 India

Correspondence should be addressed to Dinesh Kumar dkumar nitkyahoocom

Received 30 April 2013 Revised 14 August 2013 Accepted 15 August 2013

Academic Editor Zhe-Sheng Chen

Copyright copy 2013 Dinesh Kumar et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

An EtOH solution of 3-ketobutanehydrazide and salicylhydrazide on refluxing in equimolar ratio forms the corresponding Schiffbase LH

3(1) The latter reacts with Mn(II) Co(II) Ni(II) Cu(II) Zn(II) Cd(II) Zr(OH)

2(IV) MoO

2(VI) and UO

2(VI) ions in

equimolar ratio and forms the corresponding coordination compounds [M(LH)(MeOH)3] (2 M = Mn Co Ni) [Cu(LH)]

2(3)

[M1015840(LH)(MeOH)] (4 M1015840 = Zn Cd) [Zr(OH)2(LH)(MeOH)

2] (5) [MoO

2(LH)(MeOH)] (6) and [UO

2(LH)(MeOH)] (7)The co-

ordination compounds have been characterized on the basis of elemental analyses molar conductance spectral (IR reflectance 1HNMR ESR) studies and magnetic susceptibility measurementsThey are nonelectrolytes in DMSOThe coordination compoundsexcept 3 aremonomers in diphenylThey are active against gram-positive bacteria (S aureus B subtilis) gram-negative bacteria (Ecoli P aeruginosa) and yeast (S cerevisiae C albicans) 1 acts as a dibasic tridentate ONOdonor ligand in 2ndash7 coordinating throughits both enolic O and azomethineN atomsThe coordination compounds 2 and 3 are paramagnetic while rest of the compounds arediamagnetic A square-planar structure to 3 a tetrahedral structure to 4 an octahedral structure to 2 6 and 7 and a pentagonalbipyramidal structure to 5 are proposed

1 Introduction

Aroyl hydrazones and their coordination compounds areknown to possess the biological activities and inhibit manyenzymatic reactions in the cell Owing to their biologicalactivities such as antifungal antibacterial antimycobacte-rial antitumor anti-inflammatory anti-HIV leishmanicidaltrypanocidal inhibitor of anthrax lethal factor antidiabeticantimalarial and antipyretic there has been an increasinginterest towards the studies of the coordination compoundsof the Schiff bases containing the hydrazone moiety duringthe past few decades [1ndash12] The coordination compoundscontaining hydrazone moiety have been reported to actas analytical reagents such as polymer coatings fluorescentmaterials [13 14] enzymes inhibitors antifungalantibac-terial agents [15 16] and corrosion inhibitors [17] A perusal

of the literature reveals that much work has been carried outtowards the coordination compounds of Schiff bases con-taining salicylhydrazide moiety [18ndash27] however no workseems to be reported on the coordination compounds ofSchiff base derived from 3-ketobutanehydrazide and salicyl-hydrazide Novel noncytotoxic salicylhydrazide-containing1N inhibitors have been developed through substructure da-tabase search methods [28] The developmental progress ofthe salicylhydrazide class of 1N inhibitors was halted due tocytotoxicity issues The salicyloylhydrazide moiety has beenreported to be the minimally required substructure for 1Ninhibitory potency of the compounds [29] The salicylhy-drazides have also been proposed to inhibit 1N catalytic ac-tivity through chelation of the active site Mg2+ and they ex-hibit cytotoxicity in the nanomolar rangeThe replacement ofone of the two phenols in NN1015840-bis-salicylhydrazide with

2 Bioinorganic Chemistry and Applications

an optimally substituted heterocyclic group (heavily substi-tuted triazole groups) renders a novel class of noncytotoxicsalicylhydrazides greatly enhancing the therapeutic potentialof this class of 1N inhibitors Keeping in view the above im-portance of the compounds possessing hydrazone moietywe thought it worthwhile to synthesize and characterize theSchiff base LH

3(1) and its coordination compounds with

Mn(II) Co(II) Ni(II) Cu(II) Zn(II) Cd(II) Zr(OH)2(IV)

MoO2(VI) and UO

2(VI) ions The Schiff base and its co-

ordination compounds have also been studied for their anti-microbial activities

2 Experimental

21 Materials Manganese(II) acetate tetrahydrate cobalt(II)acetate tetrahydrate nickel(II) acetate tetrahydrate cop-per(II) acetate monohydrate ethyl acetoacetate methyl sal-icylate [Loba Chemie] hydrazine hydrate [Fisher Scientific]ammonium molybdate tetrahydrate cadmium(II) acetatedihydrate zinc(II) acetate dihydrate hexadecaaquaoctahy-droxotetrazirconium(IV) chloride [BDH] dioxourani-um(VI) acetate dihydrate [Hopkins and Williams (UK)]DMSO DMF MeOH EtOH 14-dioxane and THF [Ran-baxy] were used as received for the syntheses Bis(acet-ylacetonato)dioxomolybdenum(VI) and hexadecaaquaocta-hydroxotetrazirconium(IV) acetate were synthesized accord-ing to the literature procedures [30 31] All the microbial cul-tures were procured from microbial type culture collection(MTCC) IMTECH Chandigarh The bacteria were subcul-tured on nutrient agar whereas yeast was subcultured onmaltyeast agar

22 Analytical and Physical Measurements The estimation ofmetal contents spectral studies (IR reflectance 1H NMRESR) and the magnetic susceptibility measurements werecarried out by the methods reported earlier [32] Themeltingpoints of the compounds were determined on digital meltingpoint apparatus (Stuart SMP-40) For the purification ofKBHz SHz and 1ndash7 chromatographic separations were car-ried out using silica gel columns (160ndash200mesh) of varyinglengthThin-layer chromatography (TLC) was performed oncommercialMerck plates coatedwith a 020mm layer of silicagel The molar conductances of the coordination compoundsin DMSO were carried out using Toshniwal conductivitybridge (Model CL01-02A) and a dip type cell calibrated withKCl solution Carbon hydrogen and nitrogen contents of thecompoundswere determined on a FLASHEA 1112 CHNS (O)analyzer The IR spectra of 1ndash7 were recorded in KBr (4000ndash250 cmminus1) on a Fourier Transform Infrared spectrometer(Model RZX Perkin Elmer) The reflectance spectra were re-corded on a Hitachi-330UV-vis-NIR spectrophotometer 1HNMR spectra of 3-ketobutanehydrazide 1 4ndash7were recordedon an Avance-II (Bruker) FT NMR spectrometer at 400MHzusing DMSO as a solvent and TMS as an internal standardThe mass spectrum of 1 was recorded on Waters MicromassQ-Tof Micro-mass spectrometer The ESR spectrum of 3 wasrecorded at LNT in solid on a Varian E-112 ESR spectrometer

with X-band microwave frequency (91 GHz) using tetracya-noethylene (TCNE) as a 119892-marker and monitoring the fre-quency with a frequency meter The magnetic measurementswere carried out at room temperature by LakeshoreVSM7410instrumentThe antimicrobial studies of 1ndash7were performedby agar well diffusion method [33ndash35]

23 Antibacterial Activity A total of six microbial strainsthat is two gram-positive bacteria (S aureus B subtilis) twogram-negative bacteria (E coli P aeruginosa) and two yeasts(S cerevisiae C albicans) were screened for evaluation ofantibacterial and antifungal activities of 1ndash7 All the micro-bial cultures were adjusted to 05 McFarland standardwhich were visually comparable to a microbial suspension ofapproximately 15 times 108 cfumL 20mL of agar medium waspoured into each Petri plate and the agar plates were swabbedwith 100 120583L inocula of each test microorganism and keptfor 15min for adsorption Using sterile cork borer of 8mmdiameter wells were bored into the seeded agar plates andthese were loaded with a 100120583L volume with concentrationof 20mgmL of each compound reconstituted in DMSO Allthe plates were incubated at 37∘C for 24 h The antimicrobialactivity of each compound was evaluated by measuring thezone of growth inhibition against the test microorganismswith zone reader (Hi antibiotic zone scale) DMSO was usedas a negative control whereas ciprofloxacin and amphotericinB were used as positive controls for bacteria and yeastsrespectively

231 Determination of Minimum Inhibitory Concentration(MIC) Theminimum inhibitory concentration (MIC) is thelowest concentration of an antimicrobial compound thatinhibits the visible growth of amicroorganism after overnightincubation MIC of the various compounds against bacterialand yeast strains was tested through a modified agar well dif-fusionmethod [36] In this method a two-fold serial dilutionof each compound was prepared by first reconstituting thecompound in DMSO followed by dilution in sterile distilledwater to achieve a decreasing concentration range of 512 to1 120583gmL 100120583L of each dilution was introduced into wells(in triplicate) in the agar plates already seeded with 100120583Lof standardized inoculums (106 cfumL) of the test microbialstrain All test plates were incubated aerobically at 37∘Cfor 24 h and the inhibition zones were observed MIC wasrecorded for each test organism

24 Synthesis and Characterization

241 Synthesis of 3-Ketobutanehydrazide (KBHz) Hydrazinehydrate (50 g 100mmol) was added slowly with continuousstirring to an ice-cooled EtOH solution (20mL) of ethylacetoacetate (130 g 100mmol) during a period of 05 h Thereaction mixture was refluxed on a water bath for 2 h Thewhite compound separated out was suction filtered washedwith EtOH and recrystallised from EtOH and dried in vacuoover silica gel at room temperature The progress of the reac-tion was monitored on TLC using hexane and Et

2O (1 1 vv)

as eluent Color white M p = 188∘C Yield 104 g (90)

Bioinorganic Chemistry and Applications 3

Table 1 Analytical colour molar conductance (Ωminus1 cm2 molminus1) mass spectral and molecular weight data of compounds

S no Compound Stoichiometry Colour Yieldg () ΛM (Ωminus1 cm2 molminus1)

Found (calcd)M Wt M C H N

(1) 1 C11H14N4O3 Yellow 225(90) mdash 2501a

(250) mdash 5269(5280)

571(560)

2236(2240)

(2) 2 (M = Mn) MnC14H24N4O6 Grey 114(57) 117 3526b

(3989)1363(1376)

4208(4212)

611(602)

1417(1404)

(3) 2 (M = Co) CoC14H24N4O6 Brown 125(62) 103 4234b

(4029)1443(1462)

4182(4170)

588(596)

1372(1390)

(4) 2 (M = Ni) NiC14H24N4O6 Purple 137(68) 92 3926b

(4027)1467(1458)

4179(4172)

587(596)

1373(1391)

(5) 3 Cu2C22H24N8O6 Dark Green 112(72) 68 6184b

(6230)2052(2039)

4246(4238)

373(385)

1782(1798)

(6) 4 (M1015840 = Zn) ZnC12H16N4O4 Yellow 086(50) 56 3639b

(3454)1865(1893)

4152(4169)

473(463)

1608(1621)

(7) 4 (M1015840 = Cd) CdC12H16N4O4 White 118(60) 52 3873b

(3924)2852(2864)

3682(3670)

413(408)

1431(1427)

(8) 5 ZrC13H22N4O7 Yellow 164(75) 50 4258b

(4372)2093(2086)

3563(3568)

508(503)

1272(1281)

(9) 6 MoC12H16N4O6 Yellow 118(58) 47 4196b

(4079)2348(2351)

3523(3530)

384(392)

1352(1373)

(10) 7 UC12H16N4O6 Orange 179(65) 36 5417b

(5500)4344(4327)

2636(2618)

288(291)

1002(1018)

Abbreviations amass spectral data and bRast method data

Anal Calcd for C4H8N2O2 C 4138 H 690 N 2406

Found C 4124 H 694 N 2414 IR bands (cmminus1) 3298](OH) (intramolecular H-bond) 2899 ](NndashH) (intramolec-ular H-bond) 1677 ](C=O) (keto) 1618 120575(NH

2) and 1041

](NndashN) (hydrazide) 1H NMR (400MHz DMSO-d6 120575

ppm) 127 (s 3H ndashCH3) 258 (s 2H ndashCH

2) 526 (br 2H

ndashNH2) and 784 (br 1H ndashCONH)

242 Synthesis of Salicylhydrazide (SHz) Thetitle compoundwas synthesized according to the literature procedure [37]The progress of the reaction was monitored on TLC usinghexane and Et

2O (1 1 vv) as eluent Color white shining

crystals M p = 147∘C Yield 114 g (75) Anal Calcd forC7H8N2O2 C 5526 H 526 N 1842 Found C 5529 H

521 N 1843 IR bands (cmminus1) 3434 ](OH) (intramolec-ular H-bond) 3320 ](NndashH) (intramolecular H-bond) 1735](C=O) (keto) 1643 ](C=N) 1607 120575(NH

2) 1532 ](CndashO) (120601)

1252 ](CndashO) (enolic) 1035 ](NndashN) (hydrazide) 1H NMR(400MHz DMSO-d

6 120575 ppm) 418 (s 2H ndashNH

2) 680ndash804

(m 4H ArH) 990 (br 1H phenolic-OH) and 1233 (br 1Henolic-OH)

243 Synthesis of 1 3-Ketobutanehydrazide (116 g 100mmol) and salicylhydrazide (152 g 100mmol) were refluxedin EtOH (50mL) on a water bath for 2 hThe excess of solventwas distilled off and the yellow compound separated out wasallowed to stand at room temperature The compound wassuction filtered washed with EtOH and recrystallized fromEtOH and dried as mentioned above The progress of the re-action was monitored on TLC using hexane and Et

2O (1 1

vv) as eluent Color yellow M p = 109∘C Yield 225 g(90) Anal Calcd for C

11H14N4O3 C 5280 H 560 N

2236 Found C 5269 H 571 N 2240 IR bands (cmminus1)3267 ](OH) (intramolecular H-bond) 2720 ](NndashH) (intra-molecular H-bond) 1619 ](C=N) (azomethine) 1532](CndashO)120601 1239 ](CndashO) (enol) and 1012 ](NndashN)1H NMR(400MHz DMSO-d

6 120575 ppm) 214 (s 3H ndashCH

3) 256 (s

2H ndashCH2) 524 (d 2H ndashNH

2) 684ndash780 (m 4H ndashArH)

801 (s 1H ndashN=COH) (adjacent to aliphatic moiety) 987 (br1H ndashOH) (phenolic) 1224 (s 1H ndashN=COH) (adjacent toaromatic moiety)

244 Syntheses of 2ndash7 A MeOH solution (sim30mL) of ap-propriate metal acetate (5mmol) was added to a MeOH so-lution (sim100mL) of 1 (125 g 5mmol) with constant stirringThe solution was refluxed on a water bath for 3-4 h and thesolid residue obtained was suction filtered washed withMeOH and dried as mentioned above The resulting solidswere recrystallized from dimethyl sulfoxide (DMSO) Theprogress of the reaction was monitored on TLC using hexaneand Et

2O (1 1 vv) as eluent Color mentioned in Table 1

Yield 50ndash75 The compounds are stable up to 250∘C andthey get decomposed above this temperature 1H NMRspectral data of these coordination compounds are given inTable 3 We were unable to get the compounds (1ndash7) incrystalline forms therefore their studies related with X-raystructural determinations could not be carried out

3 Results and Discussion

The nucleophilic addition reaction between 3-ketobutanehy-drazide and salicylhydrazide in equimolar ratio in EtOH fol-lowed by the elimination of one water molecule results in theformation of the Schiff base LH

3(1) (Scheme 1)


C O

C O

HN

C N

N C

O

HO

H

C O

HN

C

OHN

HOC OH

C N

N C

HO

OH

N

Reflux+ EtOH

(1)

CH3

CH2

NH2

H2NCH3

CH3

CH2 CH2

NH2 NH2

minusH2O

Scheme 1 Synthesis of the Schiff base

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

LH3(1) + [MoO2(acac)2]

[M(LH)(MeOH)3] (2) + 2AcOH + 4H2O(M = Mn Co Ni)

[Cu(LH)]2 (3) + 4AcOH + 2H2O

[M998400(LH)(MeOH)] (4) + 2AcOH + 2H2O(M998400 = Zn Cd)

4[Zr(OH)2(LH)(MeOH)2] (5) + 8AcOH + 16H2O

[MoO2(LH)(MeOH)] (6) + 2acacH

[UO2(LH)(MeOH)] (7) + 2AcOH + 2H2O

4LH3(1) + [Zr4(OH)8(H2O)16](OAc)8

LH3 (1) + M(OAc)2middot4H2O

2LH3 (1) + 2Cu(OAc)2middotH2O

LH3 (1) + M998400(OAc)2middot2H2O

LH3 (1) + UO2(OAc)2middot2H2O

Scheme 2 Synthesis of complexes 2-7

A MeOH solution of 1 reacts with a MeOH solution ofMn(II) Co(II) Ni(II) Cu(II) Zn(II) Cd(II) Zr(OH)

2(IV)

MoO2(VI) and UO

2(VI) ions and forms the corresponding

coordination compounds 2ndash7 (Scheme 2)The coordination compounds are insoluble in H

2O

EtOH dioxane and THF but they were soluble in DMFand DMSOTheir molar conductance data (36ndash117Ωminus1 cm2molminus1 in DMSO) reveal their nonelectrolytic natureThey arestable up to 250∘C and get decomposed above this temper-ature Attempts to obtain single crystal suitable for X-ray de-termination were unsuccessful The structures of the synthe-sized ligand and metal complexes (Schemes 1 and 2) wereestablished with the help of elemental analyses data IR andNMR spectra

31 Infrared Spectral Studies The IR spectra of KBHz and 1ndash7were recorded in KBr The ](C=N) (azomethine) stretch of 1shifts to lower energy by 7ndash24 cmminus1 indicating coordinationthrough its azomethine N atom [38] The ](CndashO)120601 stretch of1 occurring at 1532 cmminus1 remains unaltered in 2ndash7 indicatingthe noninvolvement of phenolic O atom towards coordi-nation [39] The ](CndashO) (enolic) stretch of the Schiff baseshifts from 1239 cmminus1 to higher energy by 8ndash18 cmminus1 in 2ndash7indicating coordination through its enolic O atom [39]Thus1 behaves as a dibasic tridentate ONO donor ligand in 2ndash7coordinating through its azomethine N and both enolic OatomsThe involvement of enolic O and azomethine N atoms

towards coordination is further supported by the appearanceof new nonligand bands between 571ndash594 and 478ndash483 cmminus1due to the ](MndashO) and ](MndashN) vibrations in 2ndash7 Thesebands are in the expected order of increasing energy ](MndashN)lt ](MndashO) [40] as expected due to the greater dipolemoment change in the MndashO vibration greater electroneg-ativity of the O atom than N atom and shorter MndashObond length than the MndashN bond length [41] The absenceof a band between 835ndash955 cmminus1 characteristic of the](Zr=O) stretch [42] and the appearance of a new bandat 1125 cmminus1 due to 120575(ZrndashOH) bending mode in 5 suggeststhe structure of 5 structure as [Zr(OH)

2(LH)(MeOH)

2] and

not as [ZrO(H2O)(LH)(MeOH)

2] The ]s(O=Mo=O) and

]as(O=Mo=O) stretches occur at 925 and 900 cmminus1 respec-tively in 6 and these bands occur in the usual range(892ndash964 cmminus1 840ndash925 cmminus1) reported for the major-ity of MoO

2(VI) compounds [43] The presence of the

]s(O=Mo=O) and ]as(O=Mo=O) bands indicates a cis-MoO2

structure as the compounds with a trans-MoO2

struc-ture exhibit only the ]as(O=Mo=O) stretch since the]s(O=Mo=O) stretch is IR inactive [44] The absence of aband at sim770 cmminus1 in the present MoO

2(VI) coordina-

tion compound indicates the absence of an oligomericstructure with sdot sdot sdotMo=Osdot sdot sdotMo=Osdot sdot sdot interaction [43] The]as(O=U=O) stretch in 7 occurs at 930 cmminus1 This bandoccurs in the usual range (870ndash950 cmminus1) observed for themajority of trans-UO

2compounds [45]


Table 2 IR reflectance spectral data (cmminus1) and magnetic moments of the coordination compounds

S no Compound ] (C=N) (azomethine) ] (CndashO) (enolic) ]max (cmminus1) Magnetic moment (BM)

(1) 1 1619 1239 mdash mdash(2) 2 (M = Mn) 1604 1256 15860 21275 25850 586(3) 2 (M = Co) 1601 1247 9091 13698 19820 478(4) 2 (M = Ni) 1605 1257 9250 15360 24095 317(5) 3 1605 1248 14750 20150 176(6) 4 (M1015840 = Zn) 1606 1257 mdash Diamagnetic(7) 4 (M1015840 = Cd) 1608 1254 mdash Diamagnetic(8) 5 1612 1250 mdash Diamagnetic(9) 6 1598 1252 mdash Diamagnetic(10) 7 1595 1248 mdash Diamagnetic

Table 3 NMR spectral data of the coordination compounds

S no Compound Stoichiometry 1HNMR (400MHz DMSO-d6) 120575 (ppm)

(1) 4 (M1015840 = Zn) ZnC12H16N4O4

127 (t 3H ndashCH3) 206 (s 3H ndashCH3) (MeOH)256 (s 1H ndashCH) 353 (br 1H ndashOH) (MeOH) 514 (d 2H ndashNH2)694ndash780 (m 4H ArndashH) 850 (br 1H ndashNH) 987 (br 1H ndashOH)(phenolic)

(2) 4 (M1015840 = Cd) CdC12H16N4O4

125 (t 3H ndashCH3) 215 (s 3H ndashCH3) (MeOH)258 (s 1H ndashCH) 316 (br 1H ndashOH) (MeOH)514 (d 2H ndashNH2) 674ndash788 (m 4H ArndashH) 856 (br 1H ndashNH) 987(br 1H ndashOH) (phenolic)

(3) 5 ZrC13H22N4O7

130 (t 3H ndashCH3) 215 (s 3H ndashCH3) (MeOH) 250 (s 3H ndashCH3)(MeOH) 258 (s 1H ndashCH) 316 (br 2H ndashOH) 326 (br 2H ndashOH)(MeOH) 514 (d 2H ndashNH2) 674ndash788 (m 4H ArndashH) 872 (br 1HndashNH) 987 (br 1H ndashOH) (phenolic)

(4) 6 MoC12H16N4O6

125 (t 3H ndashCH3) 225 (s 3H ndashCH3) (MeOH)256 (s 1H ndashCH) 345 (br 1H ndashOH) (MeOH)511 (d 2H ndashNH2) 653ndash750 (m 4H ArndashH) 887 (br 1H ndashCONH)990 (br 1H ndashOH) (phenolic)

(5) 7 UC12H16N4O6


32 Reflectance Spectral Studies The coordination com-pound 2 (M = Mn) shows three bands at 15860 21275and 25850 cmminus1 due to the 6A

1g rarr4T1g(G)(]1) 6A1g rarr

4T2g(G)(]2) and 6A1g rarr 4A1g(G) (]3) transitions respec-

tively in an octahedral environment [46] The coordinationcompound 2 (M = Co) shows three bands at 9091 13698and 19820 cmminus1 due to the 4T

1g(F) rarr 4T2g(F)(]1) 4T1g(F)rarr4A2g(F)(]2) and 4T1g(F) rarr 4T1g(P)(]3) transitions re-

spectively in an octahedral environment [46] Using the freeion value of B = 971 cmminus1 the values of spectral parameters[46] in 2 (M = Co) are as follows 10Dq = 10253 cmminus1B1015840 = 79274 cmminus1 120573 = B1015840B = 082 1205730 = 18 and CFSE =ndash9820 kJmolminus1 The value of ]

3]1is 218 and this value

falls in the usual range (200ndash280) observed for the major-ity of octahedral Co(II) coordination compounds [46]The coordination compound 2 (M = Ni) shows threebands at 9250 15360 and 24095 cmminus1 due to the 3A

2g(F)rarr3T2g(F)(]1) 3A2g(F) rarr 3T

1g(F)(]2) and 3A2g(F) rarr

3T1g(P)(]3) transitions respectively suggesting an octahedral

geometry around the metal ion [46] Using the free ionvalue of B = 1030 cmminus1 the values of spectral parametersin 2 (M = Ni) are as follows 10Dq = 9250 cmminus1 B1015840 =74374 cmminus1120573= 0721205730 = 28 andCFSE= ndash13279 kJmolminus1The value of the ]

2]1is 166 and this value lies in the

usual range (16ndash18) reported for the majority of octa-hedral Ni(II) coordination compounds [46] The 10Dqvalue of the Co(II) coordination compound is greater thanthat of the corresponding Ni(II) coordination compound10253 cmminus1 gt 9250 cmminus1 This is in line with the spectro-chemical series of metal ions for a given ligand given stoi-chiometry and a given stereochemistry Co(II) gtNi(II) [46]The 1205730 value of the Co(II) coordination compound is less ascompared to that of the corresponding Ni(II) coordinationcompound 18 lt 28This is in line with the nephelauxeticmetal ion series in terms of 120573 and 1205730 for a given liganda given stoichiometry and a given stereochemistry [46]The coordination compound 3 shows two bands one at


14750 cmminus1 and the other at 20150 cmminus1 due to the 2B1g rarr

2A1g and 2B

1g rarr2Eg transitions respectively indicating

a square-planar configuration around the metal ion [46](Table 2)

33 1H NMR Studies The 1H NMR spectra of KBHz 1 and4ndash7 were recorded in DMSO-d

6 The chemical shifts (120575) are

expressed in ppm downfield from TMS [47] The Schiffbase (1) exhibits a singlet at 120575 214 ppm due to the methylprotons a singlet at 120575 256 ppm due to the methylene protona doublet at 120575 524 ppm due to the ndashNH

2protons a broad

signal at 120575 987 ppm due to the phenolic proton a multiplet at120575 684ndash780 ppm due to the aromatic protons a singlet at120575 801 ppm due to ndashN=COH (adjacent to aliphatic moiety)proton and a singlet at 120575 1224 ppm due to ndashN=COH(adjacent to aromatic moiety) proton The absence of theresonance signals at 120575 801 ppm and 120575 1224 ppm due to theenolic protons (adjacent to aliphatic and aromatic moietiesresp) in 4ndash7 indicates the deprotonation of the enolic protonsfollowed by the involvement of both enolic O atoms towardscoordination

34 ESR Spectral Studies TheESR spectrum of 3 in DMSO atliquid nitrogen temperature was recorded in X-band using100 kHz field modulation and the 119892 values are relative to thestandard marker tetracyanoethylene (TCNE) (119892 = 20023)The observed values of 119892

|| 119892perp 119892av and 119866 are 215 208 211

and 184 respectively From the observed values of variousparameters it is concluded that the unpaired electron liesin 119889119909

2minus 1199102 orbital giving 2119861

1as the ground state with

119892||gt 119892perpgt 2 indicating square planar geometry around the

copper(II) ion [48 49]

35 Magnetic Measurements The magnetic moments of 2(M = Mn Co Ni) are 586 478 and 317 BM respectivelyThese values lie in the normal ranges reported for themajorityof magnetically dilute octahedral compounds of Mn(II)Co(II) and Ni(II) ions [46]Themagnetic moment of 3 (M =Cu) is 176 BM indicating square planar geometry aroundthe Cu(II) ion [46] The coordination compounds 4ndash7 arediamagnetic

36 Antimicrobial Studies The newly synthesized com-pounds (1ndash7) were screened for their antibacterial and anti-fungal activities (Tables 4 and 5) The compounds 1 2 (M =Co Ni) and 3ndash7 possessed variable antibacterial activitiesagainst the gram-positive bacteria (S aureus B subtilis) Thecompounds 3 and 4 (M1015840 = Zn) displayed activities againstgram-negative bacteria (E coli)The compound 2 (M = Mn)displayed antifungal activities against yeasts (S cerevisiae Calbicans) Positive controls produced significantly sized inhi-bition zones against the tested bacteria and fungi howevernegative control produced no observable inhibitory effectagainst any of the test organisms (Figures 1 and 2) On thebasis of maximum inhibitory activities shown against gram-positive bacteria the compounds 3 and 4 (M1015840 = Zn) werefound to be most effective against S aureus with zone of in-hibition of 226mmand 213mmThe compound 3was found

Dia

met

er o

f gro

wth

of 30

25201510

50

SaBsEc

PaScCa

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B

Compoundsstandard

inhi

bitio

n zo

ne

Figure 1 Bar Chart indicating the diameter of growth of inhibitionzone for compoundsstandard against various microbes

SaBsEc

PaScCa

0

Compoundsstandard

600

500

400

300

200

100

MIC

(120583g

mL)

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B

Figure 2 Bar Chart indicating minimum inhibitory concentration(MIC) (120583gmL) for compoundsstandard against various microbesAbbreviations Sa S aureus Bs B subtilis Ec E coli Pa Paeruginosa Sc S cerevisiae Ca C albicans

to be most effective against B subtilis showing the zone ofinhibition of 253mm Among gram-negative bacteria thecompounds 3 and 4 (M1015840 = Zn) displayed antibacterial activ-ities with zone of inhibition of 153mm and 126mm againstE coliThe compound 2 (M =Mn) showed zone of inhibitionranging between 130mm against S cerevisiae and 153mmagainst C albicans The MIC of various compounds rangedbetween 16 120583gmL and 256120583gmL against gram-positive bac-teria while it ranged between 128120583gmL and 512120583gmLagainst gram-negative bacteria The compounds 3 and 4(M1015840 = Zn) were found to be the best as they exhibit the lowestMIC of 32 120583gmL against S aureus The compound 3 showedlowestMICof 16 120583gmL againstB subtilis However in case of


Table 4 In vitro antimicrobial activity of synthetic chemical compounds through agar well diffusion method

Compound no Diameter of growth of inhibition zone (mm)a

S aureus B subtilis E coli P aeruginosa S cerevisiae C albicans1 193 216 mdash mdash mdash mdash2 (M = Mn) mdash mdash mdash mdash 130 1532 (M = Co) 153 173 mdash mdash mdash mdash2 (M = Ni) 136 156 mdash mdash mdash mdash3 226 253 153 mdash mdash mdash4 (M1015840 = Zn) 213 226 126 mdash mdash mdash4 (M1015840 = Cd) 186 203 mdash mdash mdash mdash5 146 193 mdash mdash mdash mdash6 163 223 mdash mdash mdash mdash7 176 206 mdash mdash mdash mdashCiprofloxacin 266 240 250 220 mdash mdashAmphotericin B mdash mdash mdash mdash 193 166mdash no activity avalues including diameter of the well (8mm) are means of three replicates

Table 5 Minimum inhibitory concentration (MIC) (120583gmL) of compounds by using modified agar well diffusion method

Compound no S aureus B subtilis E coli P aeruginosa S cerevisiae C albicans1 64 32 mdash mdash mdash mdash2 (M = Mn) mdash mdash mdash mdash 128 1282 (M = Co) 128 128 mdash mdash mdash mdash2 (M = Ni) 256 128 mdash mdash mdash mdash3 32 16 128 mdash mdash mdash4 (M1015840 = Zn) 32 32 512 mdash mdash mdash4 (M1015840 = Cd) 64 64 mdash mdash mdash mdash5 64 64 mdash mdash mdash mdash6 64 32 mdash mdash mdash mdash7 128 128 mdash mdash mdash mdashCiprofloxacin 625 625 625 625 mdash mdashAmphotericin B mdash mdash mdash mdash 125 125mdash no activity

yeasts the compound 2 (M = Mn) showed MIC value of 128120583gmL The compound 3 was found to be the best in in-hibiting the growth of bacteria thus it can be further usedas an antibacterial agent in pharmaceutical industry formankind after testing its toxicity to human beings It isworth to mention that the antimicrobial activity of theligand (1) is greatly enhanced after coordination [50ndash52]Thelipid membrane surrounding the cell favours the passage ofonly lipid-soluble materials therefore the liposolubility isan important factor which controls the antimicrobial activity[53 54] On chelation the polarity of themetal ion is reducedto a greater extent due the overlapping of the ligand orbitaland partial sharing of the positive charge of themetal ionwithdonor groups Moreover delocalization of the 120587-electronsover the whole chelate ring is increased and the lipophilicityof the coordination compounds is enhanced The increasedlipophilicity enhances the penetration of the coordinationcompounds into the lipid membranes and blocks the metalbinding sites in the enzymes of microorganisms Thesecoordination compounds also disturb the respiration processof the cell and thus block the synthesis of proteins which

restricts further growth of the microorganisms In generalcoordination compounds are more active than ligand

4 Conclusions

On the basis of the analytical data valence requirementsconductance spectral studies and magnetic susceptibilitymeasurements it is proposed that 1 acts as a monobasictridentate ONO donor ligand in 2ndash7 coordinating throughits azomethine N and both enolic O atoms 2 and 3 areparamagnetic while 4ndash7 are diamagnetic The data suggesta square-planar structure to 3 a tetrahedral structure to 4an octahedral structure to 2 6 and 7 and a pentagonalbipyramidal structure to 5 The coordination compoundsshow significant enhanced antimicrobial activities as com-pared to the free Schiff base (Scheme 3) Therefore thesecompounds can be further used in pharmaceutical industryas antimicrobial agents for mankind after testing its toxicityto human beings


C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A

(2) (M = Mn Co Ni A = MeOH)

NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N

(4) (M998400 = Zn Cd A = MeOH) (5) (A = MeOH)

A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment

Silky Chadda is highly thankful to the authorities of theNational Institute of Technology Kurukshetra HaryanaIndia for providing an institutional fellowship to carry outthe above work

References

[1] S Shah R Vyas and R H Mehta ldquoSynthesis characterizationand antibacterial activities of somenew Schiff base compoundsrdquoJournal of Indian Chemical Society vol 69 no 9 pp 590ndash5961992

[2] S N Pandeya D Sriram G Nath and E D Clercq ldquoSynthesisantibacterial antifungal and anti-HIV activities of Schiff andMannich bases derived from isatin derivatives and N-[4-(41015840-chlorophenyl)thiazol-2-yl] thiosemicarbaziderdquo European Jour-nal of Pharmaceutical Sciences vol 9 no 1 pp 25ndash31 1999

[3] P G More R B Bhavankar and S C Patter ldquoSynthesis andbiological activity of Schiff bases of aminothiazolesrdquo Journal ofIndian Chemical Society vol 78 no 9 pp 474ndash475 2001

[4] A C L Leite R S de Lima D R Moreira et al ldquoSynthesisdocking and in vitro activity of thiosemicarbazones aminoacyl-thiosemicarbazides and acyl-thiazolidones against Trypano-soma cruzirdquo Bioorganic Medicinal Chemistry vol 14 no 11 pp3749ndash3757 2006

[5] T L Smalley A J Peat J A Boucheron et al ldquoSynthesis andevaluation of novel heterocyclic inhibitors of GSK-3rdquo Bioor-ganic Medicinal Chemistry Letters vol 16 no 8 pp 2091ndash20942006

[6] S Gemma G Kukreja C Fattorusso et al ldquoSynthesis of N1-arylidene-N2-quinolyl- and N2-acrydinylhydrazones as potentantimalarial agents active against CQ-resistant P falciparumstrainsrdquo Bioorganic Medicinal Chemistry Letters vol 16 pp5384ndash5388 2006

[7] A Nayyar V Monga A Malde E Coutinho and R Jain ldquoSyn-thesis anti-tuberculosis activity and 3D-QSAR study of 4-(adamantan-1-yl)-2-substituted quinolinesrdquo Bioorganic Medic-inal Chemistry vol 15 no 2 pp 626ndash640 2007

[8] M L Hanna T M Tarasow and J Perkins ldquoMechanisticdifferences between in vitro assays for hydrazone-based smallmolecule inhibitors of anthrax lethal factorrdquo Bioorganic Medic-inal Chemistry vol 35 no 1 pp 50ndash58 2007

[9] G Visbal E Marchan A Maldonado Z Simoni and M Nav-arro ldquoSynthesis and characterization of platinum-sterol hydra-zone complexes with biological activity against Leishmania (L)Mexicanardquo Journal of Inorganic Biochemistry vol 102 no 3 pp547ndash554 2008

[10] P Kumar B Narasimhan D Sharma V Judge and R NarangldquoHansch analysis of substituted benzoic acid benzylidenefu-ran-2-yl-methylene hydrazides as antimicrobial agentsrdquo Euro-pean Journal of Medicinal Chemistry vol 44 pp 1853ndash18632009

[11] D Kumar V Judge R Narang et al ldquoBenzylidene2-chlorob-enzylidene hydrazides synthesis antimicrobial activity QSARstudies and antiviral evaluationrdquo European Journal of MedicinalChemistry vol 45 pp 2806ndash2816 2010

[12] G A R Yaul V V Dhande S G Bhadange and A S AswarldquoSynthesis structural studies and biological activity ofdioxomolybdenum(VI) dioxotungsten(VI) thorium(IV) anddioxouranium(VI) complexes with 2-hydroxy-5-methyl and

2-hydroxy-5-chloroacetophenone benzoylhydrazonerdquo RussianJournal of Inorganic Chemistry vol 56 no 4 pp 549ndash5542011

[13] D F Martin G A Janusonis and B B Martin ldquoStabilitiesof bivalent metal complexes of some 120573-ketoiminesrdquo Journal ofAmerican Chemical Society vol 83 no 1 pp 73ndash75 1961

[14] RM E Bahnasawy A S E Tabl E E Shereafy T I Kashar andY M Issa ldquoMononuclear and binuclear copper(II) complexesof phenylhydrazoacetylacetone isonicotinoylhydrazonerdquo PolishJoural of Chemistry vol 73 no 12 pp 1925ndash1936 1999

[15] A Campos J R Anacona and M M C Vallette ldquoSynthesisand IR study of a zinc(II) complex containing a tetradentatemacrocyclic Schiff base ligand antifungal propertiesrdquo MainGroup Metal Chemistry vol 22 no 5 pp 283ndash288 1999

[16] M Verma S N Pandeya K N Singh and J P Stables ldquoAnti-convulsant activity of Schiff bases of isatin derivativesrdquo ActaPharmaceutica vol 54 no 1 pp 49ndash56 2004

[17] A S Fouda G E Badr and M N El-Haddad ldquoThe inhibitionof C-steel corrosion in H

3PO4solution by some furfural hydra-

zone derivativesrdquo Journal of the Korean Chemical Society vol52 no 2 pp 124ndash132 2008

[18] K K Narang and A Aggarwal ldquoSalicylaldehyde salicylhy-drazone complexes of some transition metal ionsrdquo InorganicaChimica Acta vol 9 no L2 pp 137ndash142 1974

[19] A Syamal and D Kumar ldquoMolybdenum complexes of bioinor-ganic interest new dioxomolybdenum(VI) complexes of Schiffbases derived from salicylaldehydes and salicylhydraziderdquoTransition Metal Chemistry vol 7 no 3 pp 118ndash121 1982

[20] A Syamal and D Kumar ldquoSpectral studies on new dioxoura-nium(VI) complexes of tridentate Schiff bases derived fromsalicylhydrazide amp salicylaldehyde or substituted salicylaldehy-desrdquo Indian Journal of Pure and Applied Physics vol 21 pp 87ndash91 1983

[21] R S Baligar andV K Revankar ldquoCoordination diversity of newmononucleating hydrazone in 3d metal complexes synthesischaracterization and structural studiesrdquo Journal of SerbianChemical Society vol 71 no 12 pp 1301ndash1310 2006

[22] Q X Yang L Z Gang LW Sheng and Z H Liang ldquoSynthesiscrystal structure and cytotoxic activity of a novel nickel(II) com-plex with Schiff base derived from salicylhydraziderdquo ChineseJournal of Structural Chemistry vol 27 pp 707ndash711 2008

[23] D A ChowdhuryM N Uddin andM A H Sarker ldquoSynthesisand characterization of dioxouranium(VI) complexes of somearoylhydrazines and their Schiff bases with acetonerdquo ChiangMai Journal of Science vol 35 pp 483ndash494 2008

[24] W Luo X T Wang X G Meng G Z Cheng and Z P JildquoMetal coordination architectures of N-acyl-salicylhydrazidesthe effect of metal ions and steric repulsion of ligands to theirstructures of polynuclear metal complexesrdquo Polyhedron vol 28pp 300ndash306 2009

[25] D Kumar P K Gupta A Kumar D Dass and A Syamal ldquoSyn-theses spectroscopic and magnetic properties of polystyrene-anchored coordination compounds of tridentate ONO donorSchiff baserdquo Journal of Coordination Chemistry vol 64 no 4pp 590ndash599 2011

[26] V A Shelke S M Jadhav S G Shankarwar A S Mundeand T K Chondhekar ldquoSynthesis characterization antibacte-rial and antifungal studies of some transition and rare earthmetal complexes of N-benzylidene-2-hydroxybenzohydraziderdquoBulletin Chemical Society of Ethiopa vol 25 no 3 pp 381ndash3912011


[27] T I A Gerber N C Yumata and R Betz ldquoThe reaction ofsalicylhydrazide with [ReOX

3(PPh3)2] Influence of X on prod-

uct formationrdquo Inorganic Chemistry Communications vol 15pp 69ndash72 2012

[28] L Q Al-Mawsawi R Dayam L Taheri M Witvrouw Z De-byser and N Neamati ldquoDiscovery of novel non-cytotoxic sali-cylhydrazide containing HIV-1 integrase inhibitorsrdquo Bioorganicand Medicinal Chemistry Letters vol 17 no 23 pp 6472ndash64752007

[29] N Neamati H Hong J M Owen et al ldquoSalicylhydrazine-containing inhibitors ofHIV-1 integrase implication for a selec-tive chelation in the integrase active siterdquo Journal of MedicinalChemistry vol 41 no 17 pp 3202ndash3209 1998

[30] G J J Chen J W McDonald and W E Newton ldquoSynthesisof Mo(IV) and Mo(V) complexes using oxo abstraction byphosphines Mechanistic implicationsrdquo Inorganic Chemistryvol 15 no 11 pp 2612ndash2615 1976

[31] D Kumar V Pandey and A Gupta ldquoStudies on the co-ordination compounds of thiazolidin-4-one derived fromsalicylaldehyde-o-hydroxyphenylureardquo International Journal ofChemical Sciences vol 9 no 3 pp 1307ndash1318 2011

[32] D Kumar A Syamal A Gupta V Pandey andM Rani ldquoCoor-dination compounds of Schiff base containing urea moietyrdquoJournal of Indian Chemical Society vol 89 no 6 pp 745ndash7522012

[33] I Ahmad and A Z Beg ldquoAntimicrobial and phytochemicalstudies on 45 Indian medicinal plants against multi-drugresistant human pathogensrdquo Journal of Ethnopharmacology vol74 no 2 pp 113ndash123 2001

[34] JMAndrews ldquoDetermination ofminimum inhibitory concen-trationsrdquo Journal of Antimicrobial Chemotherapy vol 48 no 1pp 5ndash16 2001

[35] O H S A Obaidi ldquoSynthesis characterization and theoreticaltreatment of sandwich Schiff bases complexes derived fromsalicylaldehyde with some transition metals and study of itsbiological activityrdquo International Journal of Chemistry Researchvol 3 no 2 pp 1ndash5 2012

[36] K R Aneja C Sharma and R Joshi ldquoIn vitro efficacy of amaltas(Cassia fistula L) against the pathogens causing otitis externardquoJundishapur Journal of Microbiology vol 4 no 3 pp 175ndash1832011

[37] A Syamal and D Kumar ldquoNew oxozirconium(IV) complexeswith the Schiff bases derived from salicylaldehyde substitutedsalicylaldehydes and salicylhydraziderdquo Polish Journal of Chem-istry vol 55 pp 1747ndash1750 1981

[38] A P Mishra H Purwar and R K Jain ldquoMicrowave synthesisspectral thermal and antimicrobial activities of Co(II) Ni(II)and Cu(II) metal complexes with Schiff base ligandrdquo Biointer-face Research in Applied Chemistry vol 2 no 2 pp 291ndash2992012

[39] A Syamal and K S Kale ldquoMagnetic properties of oxovana-dium(IV) complexes of some 120573-diketonesrdquo Indian Journal ofChemistry vol 17A pp 518ndash520 1979

[40] J R Ferraro Low Frequency Vibrations of Inorganic and Coordi-nation Compounds Plenum Press New York NY USA 1971

[41] D Kumar A Syamal A Gupta M Rani and P K GuptaldquoRole of pH on the formation of the coordination compoundswith the Schiff base derived from 3-formylsalicylic acid and4-amino-23-dimethyl-1-phenyl-3- pyrazolin-5-onerdquo Journal ofthe Indian Chemical Society vol 87 no 10 pp 1185ndash1197 2010


3PO4solution by some furfural

hydrazone derivativesrdquo Journal of the Korean Chemical Societyvol 52 no 2 pp 124ndash132 2008

[43] A Syamal andM RMaurya ldquoCoordination chemistry of Schiffbase complexes of molybdenumrdquo Coordination Chemistry Re-views vol 95 pp 183ndash238 1989

[44] N P Johnson C J L Lock and G Wilkinson ldquoAmine phos-phine arsine and stibine complexes of rhenium-(III) -(IV)and -(V)rdquo Journal of the Chemical Society pp 1054ndash1066 1964

[45] A Syamal ldquoCalculation of electronic spectral parameters(Dq120573 120573∘ 120582) and covalence for octahedral nickel (II) octahedralcobalt (II) and tetrahedral cobalt (II) complexesrdquo ChemistryEducation vol 4 pp 33ndash36 1987

[46] D Kumar A Syamal Jaipal and P K Gupta ldquoCoordinationcompounds of polystyrene-supported azo dyerdquo Journal of theIndian Chemical Society vol 84 no 3 pp 217ndash222 2007

[47] R M Silverstein and G C Bassler Spectrometric IdentificationofOrganic CompoundsWiley InterscienceNewYorkNYUSA2nd edition 1967

[48] O I Singh M Damayanti N R Singh R K H Singh MMohapatra and R M Kadam ldquoSynthesis EPR and bio-logical activities of bis(1-N-butylamidino-O-alkylurea)cop-per(II)chloride complexes EPR evidence for binuclear com-plexes in frozen DMF solutionrdquo Polyhedron vol 24 no 8 pp909ndash916 2005

[49] H A E Boraey R M A Rahman E M Atia and K H HilmyldquoSpectroscopic thermal and toxicity studies of some 2-amino-3-cyano-1 5-diphenylpyrrole containing Schiff bases copper(II)complexesrdquoCentral European Journal of Chemistry vol 8 no 4pp 820ndash833 2010

[50] K Singh Y Kumar P Puri M Kumar and C Sharma ldquoCobaltnickel copper and zinc complexes with 1 3-diphenyl-1H-pyrazole-4-carboxaldehyde Schiff bases antimicrobial spectro-scopic thermal and fluorescence studiesrdquo European Journal ofMedicinal Chemistry vol 52 pp 313ndash321 2012

[51] K Singh Y Kumar P Puri and G Singh ldquoSpectroscopicthermal and antimicrobial studies of Co(II) Ni(II) Cu(II) andZn(II) complexes derived from bidentate ligands containing Nand S donor atomsrdquo Bioinorganic Chemistry and Applicationsvol 2012 Article ID 729708 9 pages 2012

[52] S A Patil S N Unki A D Kulkarni V H Naik and P SBadami ldquoCo(II) Ni(II) and Cu(II) complexes with coumarin-8-yl Schiff-bases spectroscopic in vitro antimicrobial DNAcleavage and fluorescence studiesrdquo Spectrochimica Acta A vol79 no 5 pp 1128ndash1136 2011

[53] N Raman A Kulandaisamy and K Jeyasubramanian ldquoSynthe-sis structural characterization redox and antimicrobial studiesof Schiff base copper(II) nickel(II) cobalt(II) manganese(II)zinc(II) and oxovanadium(II) complexes derived from benziland 2-aminobenzyl alcoholrdquoPolish Journal of Chemistry vol 76no 8 pp 1085ndash1094 2002

[54] N Dharmaraj P Viswanathamurthi and K Natarajan ldquoRuthe-nium(II) complexes containing bidentate Schiff bases and theirantifungal activityrdquo Transition Metal Chemistry vol 26 no 1-2pp 105ndash109 2001

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


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


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


an optimally substituted heterocyclic group (heavily substi-tuted triazole groups) renders a novel class of noncytotoxicsalicylhydrazides greatly enhancing the therapeutic potentialof this class of 1N inhibitors Keeping in view the above im-portance of the compounds possessing hydrazone moietywe thought it worthwhile to synthesize and characterize theSchiff base LH

3(1) and its coordination compounds with

Mn(II) Co(II) Ni(II) Cu(II) Zn(II) Cd(II) Zr(OH)2(IV)

MoO2(VI) and UO

2(VI) ions The Schiff base and its co-

ordination compounds have also been studied for their anti-microbial activities

2 Experimental

21 Materials Manganese(II) acetate tetrahydrate cobalt(II)acetate tetrahydrate nickel(II) acetate tetrahydrate cop-per(II) acetate monohydrate ethyl acetoacetate methyl sal-icylate [Loba Chemie] hydrazine hydrate [Fisher Scientific]ammonium molybdate tetrahydrate cadmium(II) acetatedihydrate zinc(II) acetate dihydrate hexadecaaquaoctahy-droxotetrazirconium(IV) chloride [BDH] dioxourani-um(VI) acetate dihydrate [Hopkins and Williams (UK)]DMSO DMF MeOH EtOH 14-dioxane and THF [Ran-baxy] were used as received for the syntheses Bis(acet-ylacetonato)dioxomolybdenum(VI) and hexadecaaquaocta-hydroxotetrazirconium(IV) acetate were synthesized accord-ing to the literature procedures [30 31] All the microbial cul-tures were procured from microbial type culture collection(MTCC) IMTECH Chandigarh The bacteria were subcul-tured on nutrient agar whereas yeast was subcultured onmaltyeast agar

22 Analytical and Physical Measurements The estimation ofmetal contents spectral studies (IR reflectance 1H NMRESR) and the magnetic susceptibility measurements werecarried out by the methods reported earlier [32] Themeltingpoints of the compounds were determined on digital meltingpoint apparatus (Stuart SMP-40) For the purification ofKBHz SHz and 1ndash7 chromatographic separations were car-ried out using silica gel columns (160ndash200mesh) of varyinglengthThin-layer chromatography (TLC) was performed oncommercialMerck plates coatedwith a 020mm layer of silicagel The molar conductances of the coordination compoundsin DMSO were carried out using Toshniwal conductivitybridge (Model CL01-02A) and a dip type cell calibrated withKCl solution Carbon hydrogen and nitrogen contents of thecompoundswere determined on a FLASHEA 1112 CHNS (O)analyzer The IR spectra of 1ndash7 were recorded in KBr (4000ndash250 cmminus1) on a Fourier Transform Infrared spectrometer(Model RZX Perkin Elmer) The reflectance spectra were re-corded on a Hitachi-330UV-vis-NIR spectrophotometer 1HNMR spectra of 3-ketobutanehydrazide 1 4ndash7were recordedon an Avance-II (Bruker) FT NMR spectrometer at 400MHzusing DMSO as a solvent and TMS as an internal standardThe mass spectrum of 1 was recorded on Waters MicromassQ-Tof Micro-mass spectrometer The ESR spectrum of 3 wasrecorded at LNT in solid on a Varian E-112 ESR spectrometer

with X-band microwave frequency (91 GHz) using tetracya-noethylene (TCNE) as a 119892-marker and monitoring the fre-quency with a frequency meter The magnetic measurementswere carried out at room temperature by LakeshoreVSM7410instrumentThe antimicrobial studies of 1ndash7were performedby agar well diffusion method [33ndash35]

23 Antibacterial Activity A total of six microbial strainsthat is two gram-positive bacteria (S aureus B subtilis) twogram-negative bacteria (E coli P aeruginosa) and two yeasts(S cerevisiae C albicans) were screened for evaluation ofantibacterial and antifungal activities of 1ndash7 All the micro-bial cultures were adjusted to 05 McFarland standardwhich were visually comparable to a microbial suspension ofapproximately 15 times 108 cfumL 20mL of agar medium waspoured into each Petri plate and the agar plates were swabbedwith 100 120583L inocula of each test microorganism and keptfor 15min for adsorption Using sterile cork borer of 8mmdiameter wells were bored into the seeded agar plates andthese were loaded with a 100120583L volume with concentrationof 20mgmL of each compound reconstituted in DMSO Allthe plates were incubated at 37∘C for 24 h The antimicrobialactivity of each compound was evaluated by measuring thezone of growth inhibition against the test microorganismswith zone reader (Hi antibiotic zone scale) DMSO was usedas a negative control whereas ciprofloxacin and amphotericinB were used as positive controls for bacteria and yeastsrespectively

231 Determination of Minimum Inhibitory Concentration(MIC) Theminimum inhibitory concentration (MIC) is thelowest concentration of an antimicrobial compound thatinhibits the visible growth of amicroorganism after overnightincubation MIC of the various compounds against bacterialand yeast strains was tested through a modified agar well dif-fusionmethod [36] In this method a two-fold serial dilutionof each compound was prepared by first reconstituting thecompound in DMSO followed by dilution in sterile distilledwater to achieve a decreasing concentration range of 512 to1 120583gmL 100120583L of each dilution was introduced into wells(in triplicate) in the agar plates already seeded with 100120583Lof standardized inoculums (106 cfumL) of the test microbialstrain All test plates were incubated aerobically at 37∘Cfor 24 h and the inhibition zones were observed MIC wasrecorded for each test organism

24 Synthesis and Characterization

241 Synthesis of 3-Ketobutanehydrazide (KBHz) Hydrazinehydrate (50 g 100mmol) was added slowly with continuousstirring to an ice-cooled EtOH solution (20mL) of ethylacetoacetate (130 g 100mmol) during a period of 05 h Thereaction mixture was refluxed on a water bath for 2 h Thewhite compound separated out was suction filtered washedwith EtOH and recrystallised from EtOH and dried in vacuoover silica gel at room temperature The progress of the reac-tion was monitored on TLC using hexane and Et

2O (1 1 vv)

as eluent Color white M p = 188∘C Yield 104 g (90)






(250) mdash 5269(5280)

571(560)

2236(2240)

(2) 2 (M = Mn) MnC14H24N4O6 Grey 114(57) 117 3526b

(3989)1363(1376)

4208(4212)

611(602)

1417(1404)


(4029)1443(1462)

4182(4170)

588(596)

1372(1390)


(4027)1467(1458)

4179(4172)

587(596)

1373(1391)


(6230)2052(2039)

4246(4238)

373(385)

1782(1798)


(3454)1865(1893)

4152(4169)

473(463)

1608(1621)


(3924)2852(2864)

3682(3670)

413(408)

1431(1427)

(8) 5 ZrC13H22N4O7 Yellow 164(75) 50 4258b

(4372)2093(2086)

3563(3568)

508(503)

1272(1281)

(9) 6 MoC12H16N4O6 Yellow 118(58) 47 4196b

(4079)2348(2351)

3523(3530)

384(392)

1352(1373)

(10) 7 UC12H16N4O6 Orange 179(65) 36 5417b

(5500)4344(4327)

2636(2618)

288(291)

1002(1018)




2) and 1041



2) 526 (br 2H






2) 1532 ](CndashO) (120601)


6 120575 ppm) 418 (s 2H ndashNH

2) 680ndash804



2O (1 1


11H14N4O3 C 5280 H 560 N


6 120575 ppm) 214 (s 3H ndashCH

3) 256 (s









3(1) (Scheme 1)


C O

C O

HN

C N

N C

O

HO

H

C O

HN

C

OHN

HOC OH

C N

N C

HO

OH

N

Reflux+ EtOH

(1)

CH3

CH2

NH2

H2NCH3

CH3

CH2 CH2

NH2 NH2

minusH2O


RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH



[Cu(LH)]2 (3) + 4AcOH + 2H2O





4LH3(1) + [Zr4(OH)8(H2O)16](OAc)8







2(IV)

MoO2(VI) and UO



2O




2(LH)(MeOH)

2] and








2(VI) coordina-


2compounds [45]







(1) 4 (M1015840 = Zn) ZnC12H16N4O4


(2) 4 (M1015840 = Cd) CdC12H16N4O4


(3) 5 ZrC13H22N4O7


(4) 6 MoC12H16N4O6


(5) 7 UC12H16N4O6


















2A1g and 2B






2protons a broad



|| 119892perp 119892av and 119866 are 215 208 211








Dia

met

er o

f gro

wth

of 30

25201510

50

SaBsEc

PaScCa

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B

Compoundsstandard

inhi

bitio

n zo

ne


SaBsEc

PaScCa

0

Compoundsstandard

600

500

400

300

200

100

MIC

(120583g

mL)

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B











4 Conclusions



C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A


NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N


A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






(250) mdash 5269(5280)

571(560)

2236(2240)

(2) 2 (M = Mn) MnC14H24N4O6 Grey 114(57) 117 3526b

(3989)1363(1376)

4208(4212)

611(602)

1417(1404)


(4029)1443(1462)

4182(4170)

588(596)

1372(1390)


(4027)1467(1458)

4179(4172)

587(596)

1373(1391)


(6230)2052(2039)

4246(4238)

373(385)

1782(1798)


(3454)1865(1893)

4152(4169)

473(463)

1608(1621)


(3924)2852(2864)

3682(3670)

413(408)

1431(1427)

(8) 5 ZrC13H22N4O7 Yellow 164(75) 50 4258b

(4372)2093(2086)

3563(3568)

508(503)

1272(1281)

(9) 6 MoC12H16N4O6 Yellow 118(58) 47 4196b

(4079)2348(2351)

3523(3530)

384(392)

1352(1373)

(10) 7 UC12H16N4O6 Orange 179(65) 36 5417b

(5500)4344(4327)

2636(2618)

288(291)

1002(1018)




2) and 1041



2) 526 (br 2H






2) 1532 ](CndashO) (120601)


6 120575 ppm) 418 (s 2H ndashNH

2) 680ndash804



2O (1 1


11H14N4O3 C 5280 H 560 N


6 120575 ppm) 214 (s 3H ndashCH

3) 256 (s









3(1) (Scheme 1)


C O

C O

HN

C N

N C

O

HO

H

C O

HN

C

OHN

HOC OH

C N

N C

HO

OH

N

Reflux+ EtOH

(1)

CH3

CH2

NH2

H2NCH3

CH3

CH2 CH2

NH2 NH2

minusH2O


RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH



[Cu(LH)]2 (3) + 4AcOH + 2H2O





4LH3(1) + [Zr4(OH)8(H2O)16](OAc)8







2(IV)

MoO2(VI) and UO



2O




2(LH)(MeOH)

2] and








2(VI) coordina-


2compounds [45]







(1) 4 (M1015840 = Zn) ZnC12H16N4O4


(2) 4 (M1015840 = Cd) CdC12H16N4O4


(3) 5 ZrC13H22N4O7


(4) 6 MoC12H16N4O6


(5) 7 UC12H16N4O6


















2A1g and 2B






2protons a broad



|| 119892perp 119892av and 119866 are 215 208 211








Dia

met

er o

f gro

wth

of 30

25201510

50

SaBsEc

PaScCa

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B

Compoundsstandard

inhi

bitio

n zo

ne


SaBsEc

PaScCa

0

Compoundsstandard

600

500

400

300

200

100

MIC

(120583g

mL)

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B











4 Conclusions



C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A


NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N


A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


C O

C O

HN

C N

N C

O

HO

H

C O

HN

C

OHN

HOC OH

C N

N C

HO

OH

N

Reflux+ EtOH

(1)

CH3

CH2

NH2

H2NCH3

CH3

CH2 CH2

NH2 NH2

minusH2O


RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH

RefluxMeOH



[Cu(LH)]2 (3) + 4AcOH + 2H2O





4LH3(1) + [Zr4(OH)8(H2O)16](OAc)8







2(IV)

MoO2(VI) and UO



2O




2(LH)(MeOH)

2] and








2(VI) coordina-


2compounds [45]







(1) 4 (M1015840 = Zn) ZnC12H16N4O4


(2) 4 (M1015840 = Cd) CdC12H16N4O4


(3) 5 ZrC13H22N4O7


(4) 6 MoC12H16N4O6


(5) 7 UC12H16N4O6


















2A1g and 2B






2protons a broad



|| 119892perp 119892av and 119866 are 215 208 211








Dia

met

er o

f gro

wth

of 30

25201510

50

SaBsEc

PaScCa

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B

Compoundsstandard

inhi

bitio

n zo

ne


SaBsEc

PaScCa

0

Compoundsstandard

600

500

400

300

200

100

MIC

(120583g

mL)

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B











4 Conclusions



C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A


NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N


A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







(1) 4 (M1015840 = Zn) ZnC12H16N4O4


(2) 4 (M1015840 = Cd) CdC12H16N4O4


(3) 5 ZrC13H22N4O7


(4) 6 MoC12H16N4O6


(5) 7 UC12H16N4O6


















2A1g and 2B






2protons a broad



|| 119892perp 119892av and 119866 are 215 208 211








Dia

met

er o

f gro

wth

of 30

25201510

50

SaBsEc

PaScCa

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B

Compoundsstandard

inhi

bitio

n zo

ne


SaBsEc

PaScCa

0

Compoundsstandard

600

500

400

300

200

100

MIC

(120583g

mL)

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B











4 Conclusions



C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A


NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N


A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



2A1g and 2B






2protons a broad



|| 119892perp 119892av and 119866 are 215 208 211








Dia

met

er o

f gro

wth

of 30

25201510

50

SaBsEc

PaScCa

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B

Compoundsstandard

inhi

bitio

n zo

ne


SaBsEc

PaScCa

0

Compoundsstandard

600

500

400

300

200

100

MIC

(120583g

mL)

1

2 (M

= M

n)2

(M =

Co)

2 (M

= N

i) 3

4 (M

998400=

Zn)

4 (M

998400=

Cd) 5 6 7

Cipr

oflox

acin

Am

phot

eric

in B











4 Conclusions



C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A


NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N


A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of









4 Conclusions



C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A


NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N


A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


C

C O

HN

CH

O

C

HO

N

NMe A

A

M

A


NH2

Cu

O

C

HO

Cu

O

C

HO

OC

HN

CH

N

N C

CH

CO

NHN

NC

Me

Me

(3)

NH2

H2N

NC

O

HO

CON

H

NC

CH

Me

A

M998400H2N


A

A

Me

NN

C O

OH

OH

CCH

C

O

ZrOH

NH

NH2

(6) (A = MeOH)

A

HC

Me

C

O

N

N C

O

OH

O OC

HN

Mo

NH2

(7) (A = MeOH)

A

HC

Me

N

N C

OH

OCHN

U

O

O

C O

NH2

Scheme 3


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Acknowledgment


References








































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of











































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

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