Lingaiah, P

Rao, B V Mrudula

Venkatanarayana, G

English

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IndianJournalof ChemistryVol.27A, March 1988,pp.261-263Synthesis& Characterisationof TernaryComplexesofCopper(II)with2-Hydroxy-I-naphthaldehyde&a-AminoAcidsB V MRUDUI.A RAO, G VENKATANARAYANA&. P L1NGAIAH*Departmentof Chemistry,KakatiyaUniversity,Warangal506009Received8April 1987;revisedandaccepted3August1987The ternarycomplexesof Cu(I1) with 2-hydroxy-l-naph-thaldehyde(AI) and somea-amino acidshavebeensynthes-ized and characterizedby analytical,conductivity,thermal,magnetic,infrared,electronicandESR spectraldata.Basedonanalyticaland thermaldata, the stoichiometryof the com-plexesis found to be 1:1:1.The infraredspectraldataof theternarycomplexes(I) [Cu A' gly];(2) [Cu A' a-ala];(3) [Cu A'~-ala];(4) [Cu A' val];(5) [Cu A' leu];(6)[Cu A' ~-ala];(7)[CuA' ser]and (8) [Cu AI threo]indicatethatthe ligandsact asbidentateones while in the complexes(9) [Cu A' his HzO];(10)H[Cu A' asp.HzO]and (11)[Cu A'.g1ut.H20],the aminoacids act as tridentateligands.The electronicspectraof theCu(II) complexesuggesthatcomplexes1-8aresquare-planarwhile complexes9-11 are tetragonal.Variousparameterslikegll,g ~,a 2 andA. havebeencalculatedfromESR spectraldata.In continuationof our earlierwork on mixedli-gand complexesof copper(II) and dioxourani-um(VI)1.2,we report here the preparationandcharacterisationof ternary complexesof Cu(II)with 0-, 0- donor ligand 2-hydroxy-1-naph-thaldehyde(AI) and 0-, N-donors glycine(gly),DL-a-alanine(a-ala),DL-{3-alanine((3-ala),L-valine(val), L-Ieucine(leu), DL-phenylalanine(ala),DL-serine(ser),DL-threonine(threo),L-histidine(hist),L-asparticacid(asp)andL-glutamicacid(glut)..The ligand 2-hydroxy-1-naphthaldehydewasobtainedfrom SigmaChemicalCompany(USA)while a-amino acids were obtainedfrom LobaChemicalCompanyandwererecrystallizedbeforeuse. Their puritieswere checkedby TLC andmeltingpointdetermination.The followinggeneralprocedurewas adoptedfor the synthesisof ternarycomplexesof Cu(II)with 2-hydroxy-1-naphthaldehyde(AI) and the a-aminoacids:The solutionsof 2-hydroxy-1-naphthaldehyde(0.02 mol) in methanoland of aminoacid (0.02mol) in water were simultaneouslyadded to amethanolicsolutionof copperacetate(0.01mol)with constantstirring.The pH of theresultingso-lution was adjusted(6-7) by addingsodiumacet-ate.The reactionmixturewasrefluxedon a waterbath for about 30 min. On coolingthe reactionmixture,the solid complexseparatedout, whichwasfilteredandwashedwithhot waterandmeth-anol to removethe excessligandand the metalion.The complexeso obtainedweredried in vac-uooverfusedanhydrouscalciumchloride.The analyticaldata(C, H and N) for the solidcomplexeswereobtainedfrom the Micro-analyti-cal Laboratory,CalcuttaUniversity,Calcutta.Themetalcontentsin thecomplexesweredeterminedby standardprocedures3•The conductivitymea-surementswere made in DMF using a DigitalConductivitybridgemodel-304.The magneticsus-ceptibilitymeasurementsweremadeat roomtem-peratureby Gouy methodusingHg[Co(NCS)4Jasthe calibrant.DiamagneticorrectionsweremadeusingPascal'sconstants.The thermaldataof thecomplexeswereobtainedusinga Stantonthermo-balance.The infraredspectraof the ligandsandcomplexes(4000-200 cm- I) were recordedon aPerkin-Elmerinfraredspectrophotometermodel-283.The electronicspectraof thecomplexeswererecordedin DMF on a ShimadzuMultipurposespectrophotometermodel MPS-SOOO.The ESRspectraof the complexeswere recordedin solidstateat roomtemperatureon a varianV 3 Q spec-trometer.All the complexesare non-hygroscopic,stableat roomtemperature,insolublein waterandcom-mon organicsolvents,but soluble in DMF andDMSO. The molar conductancesof 1x 10-3 Msolutionsof the complexesof 1-9 (seeTable 1 )were low (10-15 ohm- 1 cm2 mol- 1) indicatingthem to be non-electrolytes.The valuesfor thecomplexes(10)and (11)were in the range40-60ohm- 1 cm2mol- 1 indicatingthat they were 1:1electrolytes4.The elementalanalysisand conduc-tivitydataof the complexessupportthe formula-tionofcomplexeshowninTable1.All thecomplexesexcept(9) to (11)werether-mallystableupto 225°Cindicatingthattheywerenot hydrated.This wasconfirmedby the absenceof endothermicpeakin the DTA curvesof thesecomplexesin the temperaturerange lS0-200°e.The complexes(9) to (11)showedan endothermicpeakin thetemperaturerange160-190°Cindicat-ing the presenceof coordinatedwaters. Theamountof waterpresentin thesecomplexeswasconfirmedby thethermogravimetriccurves.Thesecurvesshoweda mass loss in the temperaturerangeISO-200°Cwhichcorrespondedto one wa-ter molecule.All thecomplexesdecomposedin a261INDIAN J. CHEM., VOL. 27A, MARCH 1988Table I-Elemental Analyses, Electronic Spectral and Magnetic Moments of Copper(II) ComplexesS.No.Complex m.p.Found(Calc.),%vma.(cm- I) Magnetic(ec)momentMetalCHN (B.M.)[CuA' glyJ28019.8850.9634.3656251(20.66)(50.56)(3.57)4.52)2 5331.82[ uA' a-ala] 65040313 95719 712 0843703e l B 762144I val]7 6708 134 9185leu6 55047 4416a- a] 56 985 861 413 4 27s r8 459 6498th eo]24 35059hist.H2O]70. 0*I(16.15)8(1 . ) (1 81)I :10 H[Cu A' sp.H2O]*:,11(16.57)(1.82)H[CuAI glut.HP]3i 95(48.17)2) (1.83)*Broad~d indicatestheoverlappingof differentransitions.'"isingle~tepin thetemperaturerange250-500aCcorres~ndingto th lossof ligandmoiety.Thefi-nalpr~uctsof decompositionascomputedfromthepy]'lysiscorrespondedin eachcaseto metal-licoxid.The resenceof characteristicbandsof thetwoligandsin theIR spectraof th complexesindicatetheforPtationof ternarycomplexes.The bandsobservddat 3360(b)and 1725cm-I in the in-fraredIspectrumof 2-hydroxy-l-naphthaldehydeareassfgnedto stretchingvibrationsof phenolichYdroi andv(C=0)of aloehydegroup,respect-ively.T edisappearanceof theformerbandandashiftin lattertowardsl werfrequ ncyregion(35-50 cmt1) in all theternarycomplexesconfirmstheinv~lvementof phenolicoxygen,withdepro-tonatio~,andcarbonyloxygenin th coordinati n.Theb dsaround3265and3120cm-I observedin the spectraof freeaminoacidsareassignedto Vas( 2) andVs(NH2) respectively6-s.In theternarycomplexes,a shiftof theNH2 stretchingvibratios to lower frequencyside (Liv=50-80cm- 1) sows thecomplexformationthroughami-no nitr~en.Further,the free ligandsdisplayabandat 1515cm-I dueto thebendingvibrationof NH2 group.In thecomplexesthisbandunder-goesa egativeshiftto anextentof 40-50cm-1,c nfirmg theinvolvementof aminogroupin co-I262II I "illfl iill:ordination.The vasCOOandVsCOO modesofthecarboxylateanionin theIR spectraof freeam-ino acidsoccur in the regions1630-1600and1420-1400cm-I, respectively.Thesebandsareshiftedtowardsthelowerfrequencyregionby25-30 and30-40cm-1, respectivelyin theternarycomplexesindicatingtheparticipationof carboxyl-ic oxygenin coordination.Further,thedisappear-anceof thev(0- H) of thecarboxylicgroup,ap-p aringat 2600cm- I in theIR spectraof freeaminoacids,confirmsitsinvolvementin coordina-tion9•The aminoacidscontaininghydroxylgroup,like serineand threonine,show an additionalbroadbandcentredat 2800 cm- 1 due to thev(O- H). The lowerpositionof thisbandindi-catestheinvolvementof thisgroupin hydrogenbondingwith the nitrogenof the aminogroup.The·nqn-disappearanceof thisbandin theirter-narycomplexesconfirmsthenon-involvementofhydroxyloxygenin coordinationwiththecentralmetalion.In the IR spectrumof free histidine,broadbandsobservedat 3230and3160cm-I maybeassignedtotheasymmetricandsymmetricstretch-ingof theaminoandiminogrops.A shiftof thesebandstowardsthelowerregionto an extentof30-20 cm- 1 in theternarycomplexis observed;NOTESTable2-ESR SpectralDataofCopper(Il)ComplexesS.No. Complex gll g, Igi a2 -).(cm-I)1 [CuAI gly] 2.25 2.08 2.13 0.603 2492 [CuAI a-ala] 2.23 2.07 2.12 0.556 2303 [CuAI ~-ala] 2.25 2.08 2.14 0.645 2674 [CuAI val] 2.22 2.11 2.15 0.684 2835 [CuAI leu] 2.22 2.10 2.14 0.642 2666 [CuAlO-ala] 2.23 2.07 2.12 0.551 2287 [CuAI ser] 2.23 2.10 2.14 0.647 2688 [CuAlthreo] 2.22 2.10 2.14 0.648 2689 [CuAI hist.H20] 2.14 2.08 2.10 0.472 19510 H[Cu AI asp.HzO] 2.18 2.06 2.10 0.461 19111 H[Cu AI glut.HzO] 2.23 2.07 2.12 0.554 229this indicatestheinvolvementof aminoandiminonitrogensin coordinationwiththemetalion.In the complexes(9), (10) and (11) additionalbands are observedaround 3600-3200, 1630-1600and 800-700cm-1, due to the presenceofcoordinatedwater and these are assignedtov(OH), ~(HOH) andp(HOH), respectively10.Fur-ther,in the far infraredspectraall the complexesshow vibrations of v(Cu- N) and v(Cu- 0)around500and400cm-1respectivelyU-14.The electronicspectraof the copper(II)com-plexes(1)-(8) show strongbands around 15500and 25000 cm- 1 which may be assignedto2B 2g+-2Big and 2E g+-2Big transitionsrespectively(characteristicof squareplanargeometry)15,whilethe remainingcomplexes,(9)-(11), each show abroad absorptionbandaround16000cm-1. Tet-ragonal copper(ll) complexesare expectedtoshow the transitions2A1g+-2B 18'2B 2g+-2Big and2E g+-2B18'but bands due to these transitionsusually overlap to give one broad absorptionbandl6. The broad band observedin the presentcomplexesaround16000cm-1 suggeststhatit hastetragonalconfigurationaround copper(II) ion.Further, all the complexesshow bands above26000cm- 1whichareattributedto chargetrans-ferl7•All thecomplexesarefoundto beparamagnetic(Table 1) showingthe presenceof one unpairedelectron.The smallexcessoverthespin-onlyvalue(1.73 B.M.) observedin the presentcomplexesmaybe due to spin-orbitcoupling.The I-l eff. forthesecomplexeshavealsobeencalculatedandtheexperimentalvaluesare in good agreementwiththecalculatedones.The ESR spectraof Cu(ll) complexesin solidstateat room temperaturexhibittwo peaks,oneintenseabsorptionathi,ghfield andtheotherwithlower intensityat low field.From thesepeaksthevaluesof g" and g1 havebeen calculatedusingKneubuhl'smethodIX. All the complexesshowanisotropic ESR spectrawith g">g1 (Table 2),characteristicof dX2_y2 groundstatel9.The gu ob-tainedfor theseCu(II) complexesis lessthan2.3indicatingthatthemetal-ligandbondis of covalentcharacter2o.The a 2 valuesfor all the complexesfall in therange0.4-0.6indicatingthepresenceofappreciablein-planecovalency2l.The spin-orbitcouplingconstant(A.) for all thecomplexesis foundto be lessthanthatof thefreemetalion (I..°=- 828cm- l) suggestingconsider-ablemixingof groundand excitedterms.The Iglvaluesarealsousefulfor calculatingthemagneticmoments(I-l) of the complexesand the calculatedvalues are in agreementwith the experimentalones22•Two of theauthors(B V M andG V N) thankCSIR, New Delhi, for the awardof researchfel-lowships.References1 RavindarV, VenkatanarayanaG, Mrudula Rao B V, Swa-mySJ &LingaiahP, IndianJ Chern,23A(1984)336.2 Mrudula Rao B V, SwamyS J & Ligaiah P, Indian JChern,24A(1985)887.3 Vogel A I, A textbook of quantitativeinorganicanalysis(Longman,London)1968,358.4 GearyW J, CoordChemRev,7 (1971)81.5 NikolaevA V, MyachinaL I& LogvinenkoV A, Thermalanalysis,(AcademicPress,NewYork),2 (1969)779.6 Tsuboi M, Onishi K, NakagawaI, ShimaneuchiT & Mi-zushimaS,SpectrochimActa,12(1958)253.7 FukushimaK, Onishi K, ShimanouchiT & MizushimaS,SpectrochimActa,14(1959)236.8 SenD N, MizushimaS, Kurran C & QuaglianoJ V, JAmchemSoc,77(1955)211.9 YoungR P,J heterocyclicChern,9 (1972)371.10 NakamatoK, InfraredandRamanspectraof inorganicandcoordinationcompouns(Wiley,NewYork), 1978,227.11 AdamsD M, Metal ligandand relatedvibrations(Arnold,London),1967.12 PrabhakaranC P & Patel C C, J inorg nucl Chern,37(1975)1901.13 DjordjevicC, SpectrochimActa,17(1961)448.14 BehnkeG T &NakamatoK, InorgChern,6 (1967)443.15 WerdenB C, Billing E & Gray H B, InorgChern,2 (1963)97.16 NishidaY & KidaS, CoordChemRev,27(.1979)275.17 HatzieldW J & WymanR, Transitionmetalchemistry,Ed-itedbyR C Carlin(MarcelDekker,N.Y.) 1968.18 KneubuhlF K, J chemPhys,33(1960)1074.19 Ballhausen C J, Introductian to ligand field theory(McGraw-Hill,NewYork) 1962,134.20 KivelsonD K &NeimanR, J chemPhys,3S(1961)149.21 SatyanarayanaM & Sastry Siva Rama, Indian J Chern,13A(1975)611.22 LaxmaReddyK, Sri Hari S & LingaiahP, IndianJ Chern,23A(1984)172.263

Synthesis & Characterisation of Ternary Complexes of Copper(II) with 2-Hydroxy-1- naphthaldehyde & ɑ-Amino Acids

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Synthesis & Characterisation of Ternary Complexes of Copper(II) with 2-Hydroxy-1- naphthaldehyde & ɑ-Amino Acids

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