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Hindawi Publishing CorporationInternational Journal of Inorganic ChemistryVolume 2013 Article ID 847071 10 pageshttpdxdoiorg1011552013847071

Research ArticleSynthesis of New Zirconium(IV) Complexes withAmino Acid Schiff Bases Spectral Molecular Modelingand Fluorescence Studies

Har Lal Singh and Jangbhadur Singh

Department of Chemistry Faculty of Engineering amp Technology Mody Institute of Technology and ScienceLakshmangarh Sikar Rajasthan 332311 India

Correspondence should be addressed to Har Lal Singh hlsingh9rediffmailcom

Received 29 September 2012 Accepted 5 January 2013

Academic Editor Wei-Yin Sun

Copyright copy 2013 H L Singh and J Singh 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

New zirconium(IV) complexes were synthesizedwith bidentate ligands and characterized by elemental analysis molar conductancemeasurements molecular weight determinations IR electronic NMR (1H and 13C) fluorescence andmolecular modeling studiesAll the complexes are 1 2 electrolytes in nature and may be formulated as [Zr(L)

2Cl2] (where L is Schiff bases of amino acids

and substituted isatin) The analytical data showed that the Schiff-base ligand acts as bidentate toward zirconium ion via theazomethine nitrogen and carboxylate oxygenThe conductivity values between 85ndash126Ωminus1 molminus1 cm2 inDMF imply the presenceof nonelectrolyte species On the basis of spectral and molecular modeling studies the resulting complexes are proposed to haveoctahedral geometries

1 Introduction

The coordination chemistry of Schiff bases has been widelyexplored though its use in supramolecular coordinationchemistry remains largely unexplored The Schiff-base moi-ety is potentially ambidentate and can coordinate throughnitrogen with either oxygen or sulfur atoms The vast liter-ature on structural studies of Schiff-base complexes revealssome interesting features of their coordination behavior [1ndash6] Schiff-base metal chelates have played a central role inthe development of coordination chemistryMetal complexeswith Schiff-base ligands have been receiving considerableattention due to the pharmacological properties of both lig-ands and complexes [7ndash10] Schiff-base derivatives exhibit agreat variety of biological activities such as antitumor [11 12]antifungal [13 14] antibacterial [15 16] anticonvulsant [17]and antiviral [18] properties The interest in the constructionof Schiff-base coordination complexes by reacting transitionmetal ions with bidentate has been constantly growingover the past years [19ndash21] Within this understanding liesan increased knowledge of molecular self-assembly metal-ligand complexation and disposition of metal binding sites

By mastering these areas new improved systems related tothe fields of catalysis supramolecular chemistry and bioengi-neering can be achieved Although the chemistry of zirco-nium complexes has been extensively studied particularly inrelation to their application as polymerization catalysts thecoordination chemistry of these oxophilicmetals has concen-trated on the use of oxygen donors Many researchers haveconducted on Schiff-base complexesmost of these complexeswere found to be biologically active [22ndash25] as there hasbeen considerable interest in the study of first-row transitionmetal Schiff-base complexes However relatively less workhas appeared on the complexes of 2nd and 3rd rows transitionmetal ionsThere is not much information on zirconium(IV)complexes from the available literature therefore this paperreports the synthesis and characterization of zirconium(IV)complexes of Schiff bases derived from amino acids andisatins

2 Experimental

21 Starting Materials All chemicals used in the presentwork 1H-indole-23-dione 5-chloro-1H-indole-23-dione

2 International Journal of Inorganic Chemistry

Table 1 Various Bond Lengths of Compound [Zr(L4)2Cl2]

S No Atoms Actual (A) Optimal (A)1 Zr(4)-N(3) 213812 C(41)-H(66) 11131 11133 C(41)-H(65) 11126 11134 C(39)-H(64) 11137 11135 C(39)-H(63) 11153 11136 C(38)-H(62) 11125 11137 C(38)-H(61) 11135 11138 C(38)-H(60) 11127 11139 C(36)-H(59) 11132 111310 C(36)-H(58) 11141 111311 C(35)-H(57) 11142 111312 C(35)-H(56) 11132 111313 C(34)-H(55) 10939 1114 C(33)-H(54) 11023 1115 C(32)-H(53) 11023 1116 C(31)-H(52) 11016 1117 N(27)-H(51) 10444 10518 C(25)-H(50) 11159 111319 C(25)-H(49) 11146 111320 C(24)-H(48) 11012 1121 C(23)-H(47) 11061 1122 C(22)-H(46) 11049 1123 C(21)-H(45) 11012 1124 N(17)-H(44) 10446 10525 C(8)-H(43) 11138 111326 C(2)-H(42) 11165 111327 S(40)-C(41) 18167 181528 C(39)-S(40) 18236 181529 C(25)-C(39) 15388 152330 S(37)-C(38) 18142 181531 C(36)-S(37) 18255 181532 C(35)-C(36) 15393 152333 N(9)-Zr(4) 2134534 Zr(4)-O(5) 2091635 C(2)-C(35) 15486 152336 C(34)-C(29) 14014 14237 C(33)-C(34) 13978 14238 C(32)-C(33) 13994 14239 C(31)-C(32) 13929 14240 C(28)-C(31) 13971 14241 C(26)-O(30) 12293 120842 C(29)-C(15) 14774 150343 C(28)-C(29) 14077 14244 N(27)-C(28) 13928 146245 C(26)-N(27) 13678 146246 C(15)-C(26) 15141 151747 C(8)-C(25) 15398 152348 C(24)-C(19) 14832 14249 C(23)-C(24) 15134 14250 C(22)-C(23) 15149 14251 C(21)-C(22) 15092 142

Table 1 Continued

S No Atoms Actual (A) Optimal (A)52 C(18)-C(21) 14845 14253 C(16)-O(20) 13098 120854 C(19)-C(14) 15193 150355 C(18)-C(19) 1374 14256 N(17)-C(18) 13476 146257 C(16)-N(17) 13903 146258 C(14)-C(16) 15503 151759 N(3)-C(15) 12988 12660 N(9)-C(14) 21882 12661 C(1)-O(13) 12142 120862 C(7)-O(12) 12117 120863 Zr(4)-Cl(11) 2442364 Zr(4)-Cl(10) 2445365 C(8)-N(9) 14968 14766 C(7)-C(8) 15279 150967 O(6)-C(7) 13594 133868 C(41)-H(67) 11129 111369 O(5)-C(1) 13551 133870 Zr(4)-O(6) 2091471 C(2)-N(3) 15032 14772 C(1)-C(2) 15292 1509

400

200

0360 445 530

Inte

nsity

Wavelength (nm)

Figure 1 Emission spectra of the ligand (L3H)

amino acids (glycine alanine valine methionine pheny-lalanine and tryptophan) and oxozirconium(IV) chloridewere of analytical grade The ligands were prepared by thecondensation of isatins with amino acids as described earlier[9 26]

22 Analytical Procedures Solvents used were dried andpurified by standard methods and moisture was excludedfrom the glass apparatus using CaCl

2drying tubesThemelt-

ing points of the compounds were determined on a capillarymelting point apparatus andwere not correctedThe purity ofthe compounds was confirmed by thin layer chromatographyusing silica gel-G glass plates as the stationary phase and

International Journal of Inorganic Chemistry 3

Table 2 Various Bond Angles of Compound [Zr(L4)2Cl2]

S No Atoms Actual (∘) Optimal (∘)1 H(67)-C(41)-H(66) 109418 1092 H(67)-C(41)-H(65) 1089614 1093 H(67)-C(41)-S(40) 1103566 10934 H(66)-C(41)-H(65) 1087912 1095 H(66)-C(41)-S(40) 1099408 10936 H(65)-C(41)-S(40) 1093437 10937 C(41)-S(40)-C(39) 975564 9638 H(64)-C(39)-H(63) 1075686 10949 H(64)-C(39)-S(40) 1101883 11210 H(64)-C(39)-C(25) 1104229 1094111 H(63)-C(39)-S(40) 1098119 11212 H(63)-C(39)-C(25) 1091207 1094113 S(40)-C(39)-C(25) 1096938 106514 H(62)-C(38)-H(61) 1096623 10915 H(62)-C(38)-H(60) 1090937 10916 H(62)-C(38)-S(37) 1103571 109317 H(61)-C(38)-H(60) 1086879 10918 H(61)-C(38)-S(37) 1100128 109319 H(60)-C(38)-S(37) 1089946 109320 C(38)-S(37)-C(36) 98533 96321 H(59)-C(36)-H(58) 1071198 109422 H(59)-C(36)-S(37) 110417 11223 H(59)-C(36)-C(35) 1095515 1094124 H(58)-C(36)-S(37) 1107645 11225 H(58)-C(36)-C(35) 1108347 1094126 S(37)-C(36)-C(35) 1081586 106527 H(57)-C(35)-H(56) 1049845 109428 H(57)-C(35)-C(36) 1086578 1094129 H(57)-C(35)-C(2) 1108409 1094130 H(56)-C(35)-C(36) 1089072 1094131 H(56)-C(35)-C(2) 1095018 1094132 C(36)-C(35)-C(2) 1135779 109533 H(55)-C(34)-C(29) 1223033 12034 H(55)-C(34)-C(33) 1175306 12035 C(29)-C(34)-C(33) 120166136 H(54)-C(33)-C(34) 1196447 12037 H(54)-C(33)-C(32) 1194129 12038 C(34)-C(33)-C(32) 120942439 H(53)-C(32)-C(33) 1197786 12040 H(53)-C(32)-C(31) 1201954 12041 C(33)-C(32)-C(31) 119986842 H(52)-C(31)-C(32) 1211904 12043 H(52)-C(31)-C(28) 120678 12044 C(32)-C(31)-C(28) 118131345 C(34)-C(29)-C(15) 1343781 12046 C(34)-C(29)-C(28) 1171629 12047 C(15)-C(29)-C(28) 1084549 12048 C(31)-C(28)-C(29) 1230239 12049 C(31)-C(28)-N(27) 1268775 12050 C(29)-C(28)-N(27) 1100936 12051 H(51)-N(27)-C(28) 1260741 118

Table 2 Continued

S No Atoms Actual (∘) Optimal (∘)52 H(51)-N(27)-C(26) 1253088 11853 C(28)-N(27)-C(26) 108542554 O(30)-C(26)-N(27) 1208581 122655 O(30)-C(26)-C(15) 1292063 12356 N(27)-C(26)-C(15) 1099356 12257 H(50)-C(25)-H(49) 106678 109458 H(50)-C(25)-C(39) 1087135 1094159 H(50)-C(25)-C(8) 108393 1094160 H(49)-C(25)-C(39) 1112794 1094161 H(49)-C(25)-C(8) 109454 1094162 C(39)-C(25)-C(8) 1121296 109563 H(48)-C(24)-C(19) 1173341 12064 H(48)-C(24)-C(23) 117009 12065 C(19)-C(24)-C(23) 119931166 H(47)-C(23)-C(24) 1139434 12067 H(47)-C(23)-C(22) 1140848 12068 C(24)-C(23)-C(22) 118369369 H(46)-C(22)-C(23) 1158207 12070 H(46)-C(22)-C(21) 1150649 12071 C(23)-C(22)-C(21) 118147972 H(45)-C(21)-C(22) 1194891 12073 H(45)-C(21)-C(18) 1189569 12074 C(22)-C(21)-C(18) 118065875 C(24)-C(19)-C(14) 1241732 12076 C(24)-C(19)-C(18) 120434 12077 C(14)-C(19)-C(18) 1144563 12078 C(21)-C(18)-C(19) 1239331 12079 C(21)-C(18)-N(17) 1261831 12080 C(19)-C(18)-N(17) 1097946 12081 H(44)-N(17)-C(18) 126029 11882 H(44)-N(17)-C(16) 1260518 11883 C(18)-N(17)-C(16) 107870584 O(20)-C(16)-N(17) 1224042 122685 O(20)-C(16)-C(14) 1236108 12386 N(17)-C(16)-C(14) 1137879 12287 C(29)-C(15)-C(26) 1012183 117688 C(29)-C(15)-N(3) 1295068 12089 C(26)-C(15)-N(3) 129128 12090 C(19)-C(14)-C(16) 937144 117691 C(19)-C(14)-N(9) 1011826 12092 C(16)-C(14)-N(9) 1035499 12093 Zr(4)-N(9)-C(14) 104528594 Zr(4)-N(9)-C(8) 111112995 C(14)-N(9)-C(8) 111147696 H(43)-C(8)-C(25) 1081727 1093997 H(43)-C(8)-N(9) 1097641 107598 H(43)-C(8)-C(7) 1064941 107999 C(25)-C(8)-N(9) 1119987100 C(25)-C(8)-C(7) 1138847 1099101 N(9)-C(8)-C(7) 1063523102 O(12)-C(7)-C(8) 1250648 1225


Table 2 Continued

S No Atoms Actual (∘) Optimal (∘)103 O(12)-C(7)-O(6) 1246366 122104 C(8)-C(7)-O(6) 1102827 1071105 Zr(4)-O(6)-C(7) 1113282106 Zr(4)-O(5)-C(1) 1140377107 N(3)-Zr(4)-O(5) 801135108 N(3)-Zr(4)-O(6) 1286218109 N(3)-Zr(4)-N(9) 1490865110 N(3)-Zr(4)-Cl(11) 880663111 N(3)-Zr(4)-Cl(10) 842757112 O(5)-Zr(4)-O(6) 1482304113 O(5)-Zr(4)-N(9) 782701114 O(5)-Zr(4)-Cl(11) 851672115 O(5)-Zr(4)-Cl(10) 1167647116 O(6)-Zr(4)-N(9) 789572117 O(6)-Zr(4)-Cl(11) 829908118 O(6)-Zr(4)-Cl(10) 832655119 N(9)-Zr(4)-Cl(11) 1116987120 N(9)-Zr(4)-Cl(10) 860092121 Cl(11)-Zr(4)-Cl(10) 1549219122 Zr(4)-N(3)-C(15) 1210647123 Zr(4)-N(3)-C(2) 107937124 C(15)-N(3)-C(2) 120234125 H(42)-C(2)-C(35) 110432 10939126 H(42)-C(2)-N(3) 1065807 1075127 H(42)-C(2)-C(1) 1029891 1079128 C(35)-C(2)-N(3) 1181743129 C(35)-C(2)-C(1) 1098863 1099130 N(3)-C(2)-C(1) 1076576131 O(13)-C(1)-O(5) 1243628 122132 O(13)-C(1)-C(2) 1238243 1225133 O(5)-C(1)-C(2) 111734 1071

150

75

0360 445 530

Inte

nsity

Wavelength (nm)

Figure 2 Emission spectra of the Zr(L3)2Cl2complex

benzene and ethanol (9 1) as the mobile phase Zirconiumwas determined gravimetrically as its oxide ZrO

2 Nitrogen

and sulfur were determined by Kjeldahlrsquos and Messengerrsquosmethods respectivelyMolecular weight determinationswerecarried out by the Rast camphor method

23 Physical Measurements The IR spectra of samples inKBr pellets were recorded on an FTIR spectrophotometermodel SP-2 PerkinElmer in the range of 4000ndash400 cmminus1Theelectronic spectra of the ligands and their metal complexeswere recorded in dry DMSO on a thermo- double-beamspectrophotometer UV 1 in the range of 800ndash200 nm Thefluorescence studies of Schiff base and its metal complexeswere recorded on Shimadzu RF-5301PC spectrophotometerThe molar conductance of the complexes was measured on10minus3M DMF solutions using Systronics conductivity bridemodel 305 1H and 13C NMR spectra were recorded onBruker avance II (400MHz) FTNMR spectrometer at theSAIF Punjab University Chandigarh using DMSO-d

6as the

solvent and tetramethylsilane (TMS) as an internal standard

24 Molecular Modeling Studies The molecular modelingof a representative compound is carried out on a CSChem 3D ultramolecular modeling and analysis programmeinteractive graphics programme that enables rapid structurebuilding and geometry optimization with minimum energyand molecular display

25 Preparation of Zirconium Complexes The complexeswere prepared by treating oxozirconium(IV) chloride(161mmol) in methanol with the corresponding Schiff bases(322mmol) in the same solvent The mixture was refluxedfor three hours on a water bath after which the crystalsof the complex separate out on cooling the mixture wasconcentrated on a steam bath until about one-third of thesolution remained The concentrated solution was cooledafter which the crystals were filtered washed with methanoland then dried in vacuum at 45 plusmn 5∘C after repeated washingwith dry cyclohexane The compounds were purified byrecrystallization from the same solvent The purity of thecompounds was checked by TLC using silica gel G asadsorbent

Compound 119885119903(1198711)21198621198972was prepared by reacting zirco-

nium(IV) dichloride with ligand (L1H) colour red yield0218 g mp 170∘C (d) and elemental analysis () calcdfor C20H14Cl2N4O6Zr C 4226 H 248 N 986 found C

4233 H 257 N 981 molecular weight found 58012 calcd56848 Molar conductance (DMF 10minus3 Ωminus1 moLminus1 cm2)108 1H NMR (DMSO-d

6 120575 ppm 400MHz) 428 (s 2H

NndashCH2ndash) 806 (s 1H NH) 718ndash778 (m 4H aromatic)

13C NMR (DMSO 120575 ppm) 1863 (COO) 521 (ndashCH2ndash)

1538 (C=N) 1673 (C=O) 14865 1312 1299 1253 12271195 (aromatic carbons) UV-visible (120582max nm) 220 260320 370 infrared (KBr cmminus1) 120584(C=N) 1610 120584(C=O) 1722120584asym(COO) 1595 120584sym(COO) 1325 120584(Zr larr N) 535 120584(ZrndashO) 465

Compound 119885119903(1198712)21198621198972was prepared by reacting zir-

conium(IV) dichloride with ligand (L2H) colour reddish


brown yield 0317 g mp 200∘C (d) and elemental analysis() calcd for C

22H18Cl2N4O6Zr C 4430 H 304 N 939

found C 4446 H 310 N 933 molecular weight found59068 calcd 59653 Molar conductance (DMF 10minus3 Ωminus1moLminus1 cm2) 115 1H NMR (DMSO-d

6 120575 ppm 400MHz)

470 (q 1H NndashCHndash) 832 (s 1H NH) 150 (d 3H C-CH3)

700ndash786 (m 4H aromatic) 13CNMR(DMSO120575 ppm) 1807(COO) 636 (ndashCHndash) 1502 (C=N) 1596 (C=O) 15027 13831336 1317 1305 1293 1249 1211 (aromatic carbons) UV-visible (120582max nm) 220 260 320 370 infrared (KBr cmminus1)120584(C=N) 1617 120584(C=O) 1728 120584asym(COO) 1585 120584sym(COO)1322 120584(Zrlarr N) 537 120584(ZrndashO) 460


nium(IV) dichloride with ligand (L3H) colour brown yield0179 g mp 144∘C (d) and elemental analysis () calcd forC26H26Cl2N4O6Zr C 4785 H 402 N 858 found C 4789

H 414 N 854 molecular weight found 64096 calcd65264 Molar conductance (DMF 10minus3 Ωminus1 moLminus1 cm2)85 1H NMR (DMSO-d

6 120575 ppm 400MHz) 426 (d 1H Nndash

CHndash) 840 (s 1H NH) 216ndash230 (m 1H ndashCHndash) 122 (d3H ndashCH

3) 711ndash765 (m 4H aromatic) 13C NMR (DMSO

120575 ppm) 1831 (COO) 675 (ndashCHndash) 184 (ndashCH3) 1525 (C=N)

1612 (C=O) 15068 1407 13285 1315 1313 1294 12371212 (aromatic carbons) UV-visible (120582max nm) 220 260320 370 infrared (KBr cmminus1) 120584(C=N) 1616 120584(C=O) 1725120584asym(COO) 1588 120584sym(COO) 1322 (Zr larr N) 530 120584(ZrndashO) 462


conium(IV) dichloride with ligand (L4H) colour reddishbrown yield 0120 g mp 160∘C (d) and elemental analysis() calcd for C

26H26Cl2N4O6S2Zr C 4357 H 366 N 782


6 120575 ppm 400MHz)

462 (t 1HNndashCHndash) 220ndash230 (m 4H ndashCH2ndash) 156 (s 3H ndash

CH3) 800 (s 1HNH) 710ndash772 (m 4H aromatic) 13CNMR

(DMSO 120575 ppm) 1856 (COO) 623 (CH) 268 302 (CH2)

179 (CH3) 1537 (C=N) 1581 (C=O) 14486 1362 1325

12824 1226 1173 (aromatic carbons) UV-visible (120582maxnm) 218 260 378 infrared (KBr cmminus1) 120584(C=N) 1608120584(C=O) 1722 120584(NH) 3130 120584asym(COO) 1582 120584sym(COO)1310 120584(Zrlarr N) 542 120584(ZrndashO) 468


nium(IV) dichloride with ligand (L5H) colour brown yield0194 g mp 254∘C (d) and elemental analysis () calcdfor C22H16Cl4N4O6Zr C 3971 H 242 N 842 found C

3956 H 240 N 834 molecular weight found 66029calcd 66542 Molar conductance (DMF 10minus3 Ωminus1 moLminus1cm2) 119 1H NMR (DMSO-d

6 120575 ppm 400MHz) 415 (q

1H NndashCHndash) 140 (d 3H ndashCH3) 800 (s 1H NH) 702ndash

760 (m 3H aromatic) UV-visible (120582max nm) 220 260320 370 infrared (KBr cmminus1) 120584(C=N) 1612 120584(C=O) 1720120584asym(COO) 1585 120584sym(COO) 1315 120584(Zr larr N) 530 120584(ZrndashO) 460




6 120575 ppm 400MHz) 400 (t 1H

NndashCHndash) 225ndash228 (m 1H ndashCH2ndash) 840 (s 1H NH) 701ndash



nium(IV) dichloride with ligand (L7H) colour brown yield0332 g mp 210∘C (d) and elemental analysis () calcdfor C

34H26Cl2N4O6Zr C 5454 H 350 N 748 found

C 5444 H 355 N 754 molecular weight found 75564calcd 74872 Molar conductance (DMF 10minus3 Ωminus1 moLminus1cm2) 126 1H NMR (DMSO-d

6 120575 ppm 400MHz) 426

(t 1H NndashCHndashCH2ndash) 306 (d 2H ndashCH

2ndashPh) 800 (s 1H

NH) 712ndash780 (m 9H aromatic) 13CNMR (DMSO 120575 ppm)1858 (COO) 667 (ndashCHndash) 383 (ndashCH

2ndash) 159 (C=N) 1664

(C=O) 1496 1357 1331 1285 1276 1263 1245 1227 1208(aromatic carbons) UV-visible (120582max nm) 220 260 320370 infrared (KBr cmminus1) 120584(C=N) 1609 120584(C=O) 1725120584asym(COO) 1585 120584sym(COO) 1320 120584(Zrlarr N) 540 120584(ZrndashO) 460


nium(IV) dichloride with ligand (L8H) colour dark brownyield 0127 g mp 218∘C (d) and elemental analysis () calcdfor C38H28Cl2N6O6Zr C 5520 H 341 N 1016 found C

5503 H 336 N 1021 molecular weight found 82115 calcd82680 Molar conductance (DMF 10minus3 Ωminus1 moLminus1 cm2)124 1HNMR (DMSO-d

6 120575 ppm 400MHz) 436 (t 1H Nndash

CHndashCH2ndash) 322 (d 2H ndashCH

2ndash) 806 (s 1H NH) 698ndash


3 Results and Discussion

The reactions of zirconium(IV) dichloride with the mono-functional bidentate Schiff bases were carried out in drymethanol in 1 2 stoichiometric ratios and can be representedby the equation in Scheme 1

All these compounds are coloured solids insoluble incommon organic solvents and soluble in DMSO DMFCHCl

3 MeOH and so forth and insoluble in n-hexane and

petroleum ether The conductivity values for the Zr(L)2Cl2

complexes (in DMF 10minus3moL 25∘C) ranging in the 85ndash126Ωminus1 moLminus1 cm2 region indicate that the nonelec-trolytic nature of the compounds suggests that the anionsare covalently bonded The molecular weight determinationby the Rast camphor method shows that the products aremonomeric in nature

31 IR Spectra The IR absorption frequencies for the ligandsand their zirconium complexes were recorded in the range4000ndash400 cmminus1 The assignment of important infrared datafor ligand and complexes are listed in experimental section


+

R

HO

O

NH

O

ONH

N

O

ROH

O

Metal

ligan

d 1 2

N

Zr

O

O

NCl

ClO

O

HN

O

R

NH

O

R

NH

R

H

H

Cl

H

H

Cl

HH

RAbbr Abbr

Rprime

Rprime

Rprime

Rprime Rprime

RprimeH2N

L1H-L

L1H L2H

L4H

L6H

L8H

L3H

L5H

L7H

8H

ZrOCl 2

CH3

CH3

CH(CH3)2

H2C

(CH2)2SCH3

ndashH

ndash

CH(CH3)2

ndash

ndash

ndash

ndash

Scheme 1 Representative equation illustrating the formation of Schiff bases and their zirconium(IV) complexes

A strong band (due to the azomethine group) at 1620ndash1635 cmminus1 in the spectra of the free ligands [27 28] is shiftedto lower wavenumber in the complexes studied showing thecoordination of azomethine nitrogen to the metal atom [2629] The coordination of azomethine nitrogen to the metalatom is supported by the appearance of a new absorptionband at 535 cmminus1 which may be assigned to 120584(Zr larr N)vibrations [30]

The infrared spectra of all the zirconium complexes donot show the strong band in the region 3105ndash2740 cmminus1

due to 120584(COOH) indicating the deprotonation of the car-boxylate group of the Schiff bases with zirconium metalas expected It is further confirmed by the appearance ofsharp band at 465 cmminus1 in the spectra of all the complexesassignable to the 120584(ZrndashO) stretching vibrations [31] In thespectra of the complexes two sharp bands are observed at1590 and 1320 cmminus1 and are assigned to the 120584asym(COO)and 120584sym(COO) respectively Furthermore the separationbetween asymmetric and symmetric vibrations is about270 cmminus1 indicating the covalent nature of themetal-oxygen


(a) (b)

Figure 3 (a) HOMO orbitals of the MM2 geometry-optimized structure of the ligand (L4H) (b) LUMO orbitals of the MM2 geometry-optimized structure of the ligand (L4H)

Figure 4 3D molecular structure of Zr(L4)2Cl2

bond as unidentate manner Ionic bonding and also bridgingor chelation can therefore be excluded Sandhu and Vermain their studies and reports have shown that the Δ120584 valueof complexes greater by 65ndash90 cmminus1 than in their sodiumsalts indicates either asymmetric or monodentate bondingof the carboxylate group to metal atom [32] Moreover Δ120584values of complexes below 200 cmminus1 would be expected forbridging or chelating carboxylates but greater than 200 cmminus1for the monodentate bonding carboxylate anions [33] TheC=O band of the indole group appears in the range of 1720ndash1740 cmminus1 in the ligands However a strong band at 1740 cmminus1due to the vibration of C=O group remains unchanged in thespectra of complexes showing thereby the noninvolvement of

this group in coordination and thus confirms that the C=Ofrom indole is not involved in the complexation

32 Electronic Spectra The electronic spectra of Schiff basesand its zirconiumcomplexes have been recorded inmethanolIn spectrum of the ligand three bands are observed at 280300 and 380 nm The bands at 280 and 300 nm are due tothe 120587-120587lowast transitions within the aromatic ring and remainalmost unchanged in the spectra of zirconium complexesAnother band at 380 nm is due to the 119899-120587lowast transitions withinthe gtC=Nndash chromophore and shows a bathochromic shift inthe spectra of zirconium complexes due to the coordinationof azomethine nitrogen to the zirconium atom This bandshifts slightly to the higher-energy region in the spectraof zirconium complexes due to the polarization within thegtC=Nchromophore caused by the zirconium-ligand electroninteraction

33 1119867NMR Spectra The characteristic resonance peaks forthe synthesized compounds have been recorded in DMSO-d6and data are given in experimental section The expected

resonances are assigned by their peak multiplicity intensitypatterns and integration The 1H NMR spectral data of theligands show single resonance at 120575 114 plusmn 010 ppm whichis absent in the spectra of the metal complexes indicatingthe replacement of the carboxylic acid proton by the Zr(IV)moiety The ligands give a complex multiplet signal in theregion 120575 720ndash782 ppm for the aromatic protons and theseremain almost at the same position in the spectra of themetalcomplexes The appearance of signals due to NH protons atthe same positions in the ligand and its complexes shows thenon-involvement of this group in coordination

Schiff bases derived from glycine alanine valine andmethionine display fourthree aromatic protons as expectedIn the spectrum of phenylalanine the integral of the aromatic


region corresponds to nine protons five protons on thephenyl ring are recognizable at 74 ppm Methylene (forglycine alanine valine and methionine) protons on the120572-carbon of the carboxylic acid moieties appear at 396ndash430 ppmThis signal is a singlet for (1) a doublet for (3) and(6) a triplet for (7) and (8) and a quartet for (2) and (5)all of which arise from the nonequivalent methylene protonsin structures (1ndash8) In general the complexes obtained werefound to exhibit no additional resonances and thus reflectthe purity of the complexesThe integration of peaks concurswith the number of protons postulated from the structuresproposed for the complexes

34 13119862 NMR Spectra The 13C NMR spectral data for li-gands and their corresponding metal complexes have beenrecorded in experimental part Evidence of the formationof the complexes is clearly displayed in the 13C NMRspectra The 13C NMR spectra of complexes showed that the120575(COO) signal shifted to the downfield region which is lowercompared to that of the ligand (1761ndash1785 ppm) indicatingthe carboxylate anion is bonded to zirconium atom uponcomplexation The signals due to the carbon atom attachedto the azomethine group in the ligands appear at 120575 1623 plusmn090 ppmHowever in the spectra of the correspondingmetalcomplexes these appear at sim120575 1542 ppm The considerableshifts in the resonance of the carbon atom attached tonitrogen indicate the involvement of azomethine nitrogenatom of coordination The occurrence of eight resonancesin the range of 120575 1183ndash1507 ppm in the 13C NMR spectraof the complexes and ligands is defined as aromatic carbonssignals Generally the 13C NMR spectra of the complexesobtained were found to exhibit no additional resonances andthus reflected the purity of the complexes

Though it is also possible that the shifting of azomethinecarbon is due to the change in hybridization of nitrogenattached to carboxylate group but in the light of IR UVand 1H NMR spectral studies it seems more plausible thatthe shifting in these carbons is due to the involvement ofcarboxylate oxygen and azomethine nitrogen in bonding

35 Fluorescence Spectral Studies Metal-ligand coordinationmay lead to significant changes of the fluorescence propertiesof the ligand including increase of the intensity shift ofthe emission wavelength appearance of new emissions orquenching of the fluorescence The fluorescence spectra ofthe Schiff base HL1 and HL3 and their metal complexes wererecorded in DMFwith excitation wavelength 380 nm at roomtemperature (298K) The fluorescence emission spectrum ofHL1 with its metal complexes is depicted in Figures 1 and2 HL1 exhibits a strong fluorescence emission at 430 nm incontrast with this partial fluorescence quenching phenomenaare observed in its metal complexes with weak fluorescenceemission at 432 nm for zirconium(IV) HL3 shows strongfluorescence band at 435 nm and its Zr(IV) complexes exhibitweak emission bands at 436 nm respectively The maximumemission wavelength of Schiff bases is red-shifted about 10ndash20 nm owing to the formation of complex which may betentatively assigned to the ligand to metal charge transfer

(LMCT) It is evident from the fluorescence spectra thatfluorescence emission intensity of Schiff bases decreaseddramatically on complex formation with transition metalions The decrease in fluorescence intensity with formationof metal complexes is due to decrease in electron density onSchiff bases [34 35] All these fluorescent emissions may beassigned to the intraligand fluorescence since the free ligandexhibited a similar emission at 430 and 435 nm respectivelyunder the same condition

36 Molecular Modeling and Analysis The ligand (L4H) has50 filled molecular orbitals and the orbitals of the HOMOand LUMO levels are shown in Figures 3(a) and 3(b) Noticethat the HOMO orbitals are concentrated on the oxygen andnitrogen atoms while the LUMO orbitals are concentratedon the carbons of the indole rings The HOMO and LUMOenergy was found to be minus8268 eV and minus4368 eVAll the syn-thesized compounds have hexa-coordination and distortedoctahedral geometry Molecular modeling was performedfor [ZrCl

2(L4)2] as representative compound Tables 1 and

2 list selected interatomic distances and bond angles Thestructure of the complex with atomic numbering schemeis shown in Figure 4 The complex consists of two unitsof ligand molecule with metal ion Zr(IV) The complex isof six coordinates with distorted octahedral environmentaround the metal ionThe metal ion Zr(IV) is coordinated toone azomethine nitrogen atom and one carboxylate oxygenatom of Schiff-base ligand and Cl ion The ZrndashO and ZrndashNbond lengths are 2092 A and 2138 A respectively and thebond distance between ZrndashCl is 2444 A The two chloridegroups are equidistant from Zr (244 A) and complete thecoordination sphere of Zr The ClndashZrndashCl angles are 15492∘The OndashZrndashN NndashZrndashN and OndashZrndashO angles are 8011 14908and 14823∘ respectively for both the Schiff-base ligandsThese angles and distances are in good agreement with theX-ray structure of a similar zirconium complex [36]The ZrndashCl distances for the metal bound chloride groups are alsosimilar in both complexes and are comparable with reportedzirconium compounds [37]

In all 205 measurements of the bond lengths (72 innumbers) plus the bond angles (133 in numbers) are listedExcept for a few cases optimum values of both the bondlengths and the bond angles are given in the tables withthe actual values The actual bond lengthsbond angles givenin Tables 1 and 2 are calculated values as a result of energyoptimization in Chem3D Ultra and the optimum bondlengthbond angle values are the standard bond lengthsbondangles established by the builder unit of CHEM 3D Somevalues of standard bond lengthsbond angles are missingpossibly because of limitations of the software we havealready noticed this when modeling other systems In mostcases the actual bond lengths and bond angles are close tothe optimumvalues confirming the proposed structure of thecompound [Zr(L4)

2Cl]

4 Conclusion

New Schiff bases and their zirconium complexes have beensuccessfully synthesized Elemental analysis data obtained


are in good agreement with the predicted formula Dis-torted octahedral geometries have been proposed for Zr(IV)complexes with the help of various physicochemical studiesThe infrared spectra of these complexes show the presenceof monofunctional and bidentate ligands The Schiff baseexhibits a strong fluorescence emission in contrast withthis partial fluorescence quenching phenomena is observedin its metal complexes The proposed structures of metalcomplexes are presented in Figure 4 The 1H NMR spectrashowed that the calculated number of protons for eachfunctional group in the complexes is equal to the numberpredicted from the molecular formula Moreover the 1H and13C NMR spectra of the complexes obtained were found toexhibit no additional resonances and thus reflected the purityof the metal complexes

Acknowledgments

The authors are thankful to the Dean Faculty of Engineeringamp Technology Mody Institute of Technology and ScienceDeemed University Lakshmangarh Sikar for providing nec-essary facilities and financial support They are also thankfulto the Head SAIF Panjab University Chandigarh for pro-viding elemental analysis and NMR facilities The authorsare also grateful to Dr Sangeeta Jhajharia for linguisticcorrections

References

[1] G Cerchiaro K Aquilano G Filomeni G Rotilio M RCiriolo and A M D C Ferreira ldquoIsatin-Schiff base copper(II)complexes and their influence on cellular viabilityrdquo Journal ofInorganic Biochemistry vol 99 no 7 pp 1433ndash1440 2005

[2] A J Abdul-Ghani and A M N Khaleel ldquoSynthesis andcharacterization of new Schiff bases derived from N (1)-substituted isatin with dithiooxamide and their Co(II) Ni(II)Cu(II) Pd(II) and Pt(IV) complexesrdquo Bioinorganic Chemistryand Applications vol 2009 Article ID 413175 12 pages 2009

[3] R A Kusanur M Ghate and M V Kulkarni ldquoSynthesis ofspiro[indolo-l5-benzodiazepines] from 3-acetyl coumarins foruse as possible antianxiety agentsrdquo Journal of Chemical Sciencesvol 116 no 5 pp 265ndash270 2004

[4] A Ercag S O Yildirim M Akkurt M U Ozgur and FW Heinemann ldquoNovel isatin-Schiff base Cu(II) and Ni(II)complexes X-ray crystal structure of bis[3-(4-hexylphenylimi-no)-1H-indol-2(3H)-one]-dichlorocopper(II) complexrdquo Chi-nese Chemical Letters vol 17 no 2 pp 243ndash246 2006

[5] F Lu R A Zarkesh and A F Heyduk ldquoA redox-active ligandas a reservoir for protons and electrons O

2reduction at

zirconium(IV)rdquo European Journal of Inorganic Chemistry vol2012 no 3 pp 467ndash470 2012

[6] L Kakaliou W J Scanlon B Qian S W Baek M R SmithandD HMotry ldquoFive- and six-coordinate group 4 compoundsstabilized by 120573-ketiminate and diketiminate ligands synthesesand comparisons between solid-state and solution structuresrdquoInorganic Chemistry vol 38 no 26 pp 5964ndash5977 1999

[7] M Coluccia A Nassi A Boccarelli et al ldquoIn vitro and invivo antitumour activity and cellular pharmacological prop-erties of new platinum-iminoether complexes with different

configuration at the iminoether ligandsrdquo Journal of InorganicBiochemistry vol 77 no 1-2 pp 31ndash35 1999

[8] C T Supuran F Mincione A Scozzafava F Briganti GMincione and M A Ilies ldquoCarbonic anhydrase inhibitorsmdashpart 52 Metal complexes of heterocyclic sulfonamides a newclass of strong topical intraocular pressure-lowering agents inrabbitsrdquo European Journal of Medicinal Chemistry vol 33 no4 pp 247ndash254 1998

[9] H L Singh and J Singh ldquoSynthesis spectral 3D molecularmodeling and antibacterial studies of dibutyltin (IV) Schiff basecomplexes derived from substituted isatin and amino acidsrdquoNatural Science vol 4 no 3 pp 170ndash178 2012

[10] D Singh A Kumari R V Singh S M Mehta I J Gupta andK Singh ldquoAntifertility and biocidal activities of organometallicsof silicon germanium titanium and zirconium derived from2-acetylthiophene thiosemicarbazonerdquo Applied OrganometallicChemistry vol 7 no 4 pp 289ndash292 1993

[11] M P Sathisha V K Revankar and K S R Pai ldquoSynthesisstructure electrochemistry and spectral characterization of bis-isatin thiocarbohydrazone metal complexes and their antitu-mor activity against ehrlich ascites carcinoma in Swiss AlbinomicerdquoMetal-Based Drugs vol 2008 Article ID 362105 11 pages2008

[12] B Rosenberg and L VanCamp ldquoThe successful regressionof large solid sarcoma 180 tumors by platinum compoundsrdquoCancer Research vol 30 no 6 pp 1799ndash1802 1970

[13] 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

[14] A S El-Tabl M M E Shakdofa A M A El-Seidy and A NAl-Hakimi ldquoSynthesis characterization and antifungal activ-ity of metal complexes of 2-(5-((2-chlorophenyl)diazenyl)-2-hydroxybenzylidene) hydrazinecarbothioamiderdquo PhosphorusSulfur and Silicon and the Related Elements vol 187 no 11 pp1312ndash1323 2012

[15] H L Singh ldquoSynthesis and characterization of tin(II) complexesof fluorinated Schiff bases derived from amino acidsrdquo Spec-trochimica Acta A vol 76 no 2 pp 253ndash258 2010

[16] T Jeewoth H L K Wah M G Bhowon D Ghoorohoo andK Babooram ldquoSynthesis and anti-bacterialcatalytic propertiesof Schiff bases and Schiff base metal complexes derived from23-diaminopyridinerdquo Synthesis and Reactivity in Inorganic andMetal-Organic Chemistry vol 30 no 6 pp 1023ndash1038 2000

[17] S N Pandeya A S Raja and J P Stables ldquoSynthesis of isatinsemicarbazones as novel anticonvulsantsmdashrole of hydrogenbondingrdquo Journal of Pharmacy and Pharmaceutical Sciencesvol 5 no 3 pp 266ndash271 2002

[18] S P Singh S K Shukla and L P Awasthi ldquoSynthesis of some3-(41015840-nitro-benzoylhydrazone)-2-Indolinones as potential antivi-ral agentsrdquo Current Science vol 52 no 16 pp 766ndash769 1983

[19] J Strauch T H Warren G Erker R Frohlich and P Saaren-keto ldquoFormation and structural properties of salicylaldiminatocomplexes of zirconium and titaniumrdquo Inorganica ChimicaActa vol 300ndash302 pp 810ndash821 2000

[20] P G Cozzi ldquoMetal-Salen Schiff base complexes in catalysispractical aspectsrdquo Chemical Society Reviews vol 33 no 7 pp410ndash421 2004

[21] C K Modi S H Patel and M N Patel ldquoTransition metalcomplexes with uninegative bidentate Schiff base syntheticthermal spectroscopic and coordination aspectsrdquo Journal of


Thermal Analysis and Calorimetry vol 87 no 2 pp 441ndash4482007

[22] C Spınu M Pleniceanu and C Tigae ldquoBiologically activetransition metal chelates with a 2-thiophenecarboxaldehyde-derived Schiff base synthesis characterization and antibacte-rial propertiesrdquo Turkish Journal of Chemistry vol 32 no 4 pp487ndash493 2008

[23] H L Singh and A K Varshney ldquoSynthesis and characterizationof coordination compounds of organotin(IV)with nitrogen andsulfur donor ligandsrdquoAppliedOrganometallic Chemistry vol 15no 9 pp 762ndash768 2001

[24] K Sharma N Fahmi and R V Singh ldquoBiologically potent newheterobimetallic complexes of platinum silicon tin titaniumand zirconiumrdquo Main Group Metal Chemistry vol 25 no 12pp 727ndash732 2002

[25] G Rubner K Bensdorf A Wellner et al ldquoSynthesis andbiological activities of transition metal complexes based onacetylsalicylic acid as neo-anticancer agentsrdquo Journal of Medic-inal Chemistry vol 53 no 19 pp 6889ndash6898 2010

[26] H L Singh and J B Singh ldquoSynthesis and characterizationof new lead(II) complexes of Schiff bases derived from aminoacidsrdquo Research on Chemical Intermediates 2012

[27] H L Singh J B Singh and K P Sharma ldquoSynthetic struc-tural and antimicrobial studies of organotin(IV) complexesof semicarbazone thiosemicarbazone derived from 4-hydroxy-3-methoxybenzaldehyderdquo Research on Chemical Intermediatesvol 38 no 1 pp 53ndash65 2012

[28] M Nath H Singh G Eng X Song and A Kumar ldquoSynthe-ses characterization and biological activity of diorganotin(IV)derivatives of 2-amino-6-hydroxypurine (guanine)rdquo InorganicChemistry Communications vol 12 no 10 pp 1049ndash1052 2009

[29] B Khera A K Sharma and N K Kaushik ldquoBis(indenyl)ti-tanium(IV) and zirconium(IV) complexes of monofunctionalbidentate salicylidiminesrdquo Polyhedron vol 2 no 11 pp 1177ndash1180 1983

[30] V Srivastava S K Sengupta and S C Tripathi ldquoCoordinationcompounds of zirconium(lV) with thiosemicarbazonesrdquo Syn-thesis and Reactivity in Inorganic and Metal-Organic Chemistryvol 15 no 2 pp 163ndash173 1985

[31] R K Dubey A Singh and R C Mehrotra ldquoSynthesis reac-tions spectral and magnetic studies of bimetallic alkoxides ofcobalt(II) with zirconium(IV)rdquo Inorganica Chimica Acta vol118 no 2 pp 151ndash156 1986

[32] G K Sandhu and S P Verma ldquoTriorganotin(IV) derivatives offivemembered heterocyclic 2-carboxylic acidsrdquoPolyhedron vol6 no 3 pp 587ndash592 1987

[33] H L Singh and J B Singh ldquoSynthesis and characterizationof new lead(II) and organotin(IV) complexes of Schiff basesderived fromhistidine andmethioninerdquo International Journal ofInorganic Chemistry vol 2012 Article ID 568797 7 pages 2012

[34] BA Yamgar VA Sawant S K Sawant and S S Chavan ldquoCop-per(II) complexes of thiazolylazo dye with triphenylphosphineand Nminus

3or NCSminus as coligands synthesis spectral characteriza-

tion electrochemistry and luminescence propertiesrdquo Journal ofCoordination Chemistry vol 62 no 14 pp 2367ndash2374 2009

[35] XH Lu Y QHuang L Y Kong T AOkamuraW Y Sun andN Ueyama ldquoSyntheses structures and luminescent propertiesof three silver(I) complexes with a novel imidazole-containingschiff base ligandrdquo Zeitschrift fur Anorganische und AllgemeineChemie vol 633 no 11-12 pp 2064ndash2070 2007

[36] C Parnav A Kriza V Pop and S Udrea ldquoComplexes of tin(IV)and zirconium(IV) with Schiff bases derived from isatin and

diaminesrdquo Journal of the Indian Chemical Society vol 82 no1 pp 71ndash73 2005

[37] D P KrutrsquoKo M V Borzov E N Veksler A V Churakov andJ A K Howard ldquo(2-diphenylphosphinoethyl)cyclopentadienylcomplexes of zirconium (IV) synthesis crystal structure anddynamic behaviour in solutionsrdquo Polyhedron vol 17 no 22 pp3889ndash3901 1999

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


Table 1 Various Bond Lengths of Compound [Zr(L4)2Cl2]

S No Atoms Actual (A) Optimal (A)1 Zr(4)-N(3) 213812 C(41)-H(66) 11131 11133 C(41)-H(65) 11126 11134 C(39)-H(64) 11137 11135 C(39)-H(63) 11153 11136 C(38)-H(62) 11125 11137 C(38)-H(61) 11135 11138 C(38)-H(60) 11127 11139 C(36)-H(59) 11132 111310 C(36)-H(58) 11141 111311 C(35)-H(57) 11142 111312 C(35)-H(56) 11132 111313 C(34)-H(55) 10939 1114 C(33)-H(54) 11023 1115 C(32)-H(53) 11023 1116 C(31)-H(52) 11016 1117 N(27)-H(51) 10444 10518 C(25)-H(50) 11159 111319 C(25)-H(49) 11146 111320 C(24)-H(48) 11012 1121 C(23)-H(47) 11061 1122 C(22)-H(46) 11049 1123 C(21)-H(45) 11012 1124 N(17)-H(44) 10446 10525 C(8)-H(43) 11138 111326 C(2)-H(42) 11165 111327 S(40)-C(41) 18167 181528 C(39)-S(40) 18236 181529 C(25)-C(39) 15388 152330 S(37)-C(38) 18142 181531 C(36)-S(37) 18255 181532 C(35)-C(36) 15393 152333 N(9)-Zr(4) 2134534 Zr(4)-O(5) 2091635 C(2)-C(35) 15486 152336 C(34)-C(29) 14014 14237 C(33)-C(34) 13978 14238 C(32)-C(33) 13994 14239 C(31)-C(32) 13929 14240 C(28)-C(31) 13971 14241 C(26)-O(30) 12293 120842 C(29)-C(15) 14774 150343 C(28)-C(29) 14077 14244 N(27)-C(28) 13928 146245 C(26)-N(27) 13678 146246 C(15)-C(26) 15141 151747 C(8)-C(25) 15398 152348 C(24)-C(19) 14832 14249 C(23)-C(24) 15134 14250 C(22)-C(23) 15149 14251 C(21)-C(22) 15092 142

Table 1 Continued

S No Atoms Actual (A) Optimal (A)52 C(18)-C(21) 14845 14253 C(16)-O(20) 13098 120854 C(19)-C(14) 15193 150355 C(18)-C(19) 1374 14256 N(17)-C(18) 13476 146257 C(16)-N(17) 13903 146258 C(14)-C(16) 15503 151759 N(3)-C(15) 12988 12660 N(9)-C(14) 21882 12661 C(1)-O(13) 12142 120862 C(7)-O(12) 12117 120863 Zr(4)-Cl(11) 2442364 Zr(4)-Cl(10) 2445365 C(8)-N(9) 14968 14766 C(7)-C(8) 15279 150967 O(6)-C(7) 13594 133868 C(41)-H(67) 11129 111369 O(5)-C(1) 13551 133870 Zr(4)-O(6) 2091471 C(2)-N(3) 15032 14772 C(1)-C(2) 15292 1509

400

200

0360 445 530

Inte

nsity

Wavelength (nm)

Figure 1 Emission spectra of the ligand (L3H)

amino acids (glycine alanine valine methionine pheny-lalanine and tryptophan) and oxozirconium(IV) chloridewere of analytical grade The ligands were prepared by thecondensation of isatins with amino acids as described earlier[9 26]

22 Analytical Procedures Solvents used were dried andpurified by standard methods and moisture was excludedfrom the glass apparatus using CaCl

2drying tubesThemelt-

ing points of the compounds were determined on a capillarymelting point apparatus andwere not correctedThe purity ofthe compounds was confirmed by thin layer chromatographyusing silica gel-G glass plates as the stationary phase and




Table 2 Continued



Table 2 Continued


150

75

0360 445 530

Inte

nsity

Wavelength (nm)



2 Nitrogen



6as the







6 120575 ppm 400MHz) 428 (s 2H








22H18Cl2N4O6Zr C 4430 H 304 N 939


6 120575 ppm 400MHz)






6 120575 ppm 400MHz) 426 (d 1H Nndash







26H26Cl2N4O6S2Zr C 4357 H 366 N 782


6 120575 ppm 400MHz)



(DMSO 120575 ppm) 1856 (COO) 623 (CH) 268 302 (CH2)

179 (CH3) 1537 (C=N) 1581 (C=O) 14486 1362 1325





6 120575 ppm 400MHz) 415 (q






6 120575 ppm 400MHz) 400 (t 1H







6 120575 ppm 400MHz) 426


2ndashPh) 800 (s 1H


2ndash) 159 (C=N) 1664





6 120575 ppm 400MHz) 436 (t 1H Nndash












+

R

HO

O

NH

O

ONH

N

O

ROH

O

Metal

ligan

d 1 2

N

Zr

O

O

NCl

ClO

O

HN

O

R

NH

O

R

NH

R

H

H

Cl

H

H

Cl

HH

RAbbr Abbr

Rprime

Rprime

Rprime

Rprime Rprime

RprimeH2N

L1H-L

L1H L2H

L4H

L6H

L8H

L3H

L5H

L7H

8H

ZrOCl 2

CH3

CH3

CH(CH3)2

H2C

(CH2)2SCH3

ndashH

ndash

CH(CH3)2

ndash

ndash

ndash

ndash






(a) (b)



















2Cl]

4 Conclusion




Acknowledgments


References






2reduction at

















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




Table 2 Continued



Table 2 Continued


150

75

0360 445 530

Inte

nsity

Wavelength (nm)



2 Nitrogen



6as the







6 120575 ppm 400MHz) 428 (s 2H








22H18Cl2N4O6Zr C 4430 H 304 N 939


6 120575 ppm 400MHz)






6 120575 ppm 400MHz) 426 (d 1H Nndash







26H26Cl2N4O6S2Zr C 4357 H 366 N 782


6 120575 ppm 400MHz)



(DMSO 120575 ppm) 1856 (COO) 623 (CH) 268 302 (CH2)

179 (CH3) 1537 (C=N) 1581 (C=O) 14486 1362 1325





6 120575 ppm 400MHz) 415 (q






6 120575 ppm 400MHz) 400 (t 1H







6 120575 ppm 400MHz) 426


2ndashPh) 800 (s 1H


2ndash) 159 (C=N) 1664





6 120575 ppm 400MHz) 436 (t 1H Nndash












+

R

HO

O

NH

O

ONH

N

O

ROH

O

Metal

ligan

d 1 2

N

Zr

O

O

NCl

ClO

O

HN

O

R

NH

O

R

NH

R

H

H

Cl

H

H

Cl

HH

RAbbr Abbr

Rprime

Rprime

Rprime

Rprime Rprime

RprimeH2N

L1H-L

L1H L2H

L4H

L6H

L8H

L3H

L5H

L7H

8H

ZrOCl 2

CH3

CH3

CH(CH3)2

H2C

(CH2)2SCH3

ndashH

ndash

CH(CH3)2

ndash

ndash

ndash

ndash






(a) (b)



















2Cl]

4 Conclusion




Acknowledgments


References






2reduction at

















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Table 2 Continued


150

75

0360 445 530

Inte

nsity

Wavelength (nm)



2 Nitrogen



6as the







6 120575 ppm 400MHz) 428 (s 2H








22H18Cl2N4O6Zr C 4430 H 304 N 939


6 120575 ppm 400MHz)






6 120575 ppm 400MHz) 426 (d 1H Nndash







26H26Cl2N4O6S2Zr C 4357 H 366 N 782


6 120575 ppm 400MHz)



(DMSO 120575 ppm) 1856 (COO) 623 (CH) 268 302 (CH2)

179 (CH3) 1537 (C=N) 1581 (C=O) 14486 1362 1325





6 120575 ppm 400MHz) 415 (q






6 120575 ppm 400MHz) 400 (t 1H







6 120575 ppm 400MHz) 426


2ndashPh) 800 (s 1H


2ndash) 159 (C=N) 1664





6 120575 ppm 400MHz) 436 (t 1H Nndash












+

R

HO

O

NH

O

ONH

N

O

ROH

O

Metal

ligan

d 1 2

N

Zr

O

O

NCl

ClO

O

HN

O

R

NH

O

R

NH

R

H

H

Cl

H

H

Cl

HH

RAbbr Abbr

Rprime

Rprime

Rprime

Rprime Rprime

RprimeH2N

L1H-L

L1H L2H

L4H

L6H

L8H

L3H

L5H

L7H

8H

ZrOCl 2

CH3

CH3

CH(CH3)2

H2C

(CH2)2SCH3

ndashH

ndash

CH(CH3)2

ndash

ndash

ndash

ndash






(a) (b)



















2Cl]

4 Conclusion




Acknowledgments


References






2reduction at

















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



22H18Cl2N4O6Zr C 4430 H 304 N 939


6 120575 ppm 400MHz)






6 120575 ppm 400MHz) 426 (d 1H Nndash







26H26Cl2N4O6S2Zr C 4357 H 366 N 782


6 120575 ppm 400MHz)



(DMSO 120575 ppm) 1856 (COO) 623 (CH) 268 302 (CH2)

179 (CH3) 1537 (C=N) 1581 (C=O) 14486 1362 1325





6 120575 ppm 400MHz) 415 (q






6 120575 ppm 400MHz) 400 (t 1H







6 120575 ppm 400MHz) 426


2ndashPh) 800 (s 1H


2ndash) 159 (C=N) 1664





6 120575 ppm 400MHz) 436 (t 1H Nndash












+

R

HO

O

NH

O

ONH

N

O

ROH

O

Metal

ligan

d 1 2

N

Zr

O

O

NCl

ClO

O

HN

O

R

NH

O

R

NH

R

H

H

Cl

H

H

Cl

HH

RAbbr Abbr

Rprime

Rprime

Rprime

Rprime Rprime

RprimeH2N

L1H-L

L1H L2H

L4H

L6H

L8H

L3H

L5H

L7H

8H

ZrOCl 2

CH3

CH3

CH(CH3)2

H2C

(CH2)2SCH3

ndashH

ndash

CH(CH3)2

ndash

ndash

ndash

ndash






(a) (b)



















2Cl]

4 Conclusion




Acknowledgments


References






2reduction at

















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


+

R

HO

O

NH

O

ONH

N

O

ROH

O

Metal

ligan

d 1 2

N

Zr

O

O

NCl

ClO

O

HN

O

R

NH

O

R

NH

R

H

H

Cl

H

H

Cl

HH

RAbbr Abbr

Rprime

Rprime

Rprime

Rprime Rprime

RprimeH2N

L1H-L

L1H L2H

L4H

L6H

L8H

L3H

L5H

L7H

8H

ZrOCl 2

CH3

CH3

CH(CH3)2

H2C

(CH2)2SCH3

ndashH

ndash

CH(CH3)2

ndash

ndash

ndash

ndash






(a) (b)



















2Cl]

4 Conclusion




Acknowledgments


References






2reduction at

















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(a) (b)



















2Cl]

4 Conclusion




Acknowledgments


References






2reduction at

















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of











2Cl]

4 Conclusion




Acknowledgments


References






2reduction at

















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



Acknowledgments


References






2reduction at

















































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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