Das, S

Lal, R A

English

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IndianJournalof ChemistryVol.27A, March 1988,pp.225-230Synthesis& Characterizationof Nitrato& AcetatoComplexesofDioxouranium(VI)withDisalicylaldehydeAcylHydrazonesSDAS&RALAL*Departmentof Chemistry,PachhungaUniversityCollege,North-EasternHill University,Aizawl 796001,MizoramReceived20November1986;revised26May1987;re-revisedandaccepted21July 1987Dioxouranium(VI)complexesof disalicylaldehydeoxaloyldihydraZone(H4Az),malonoyldihydrazone(~Bz),succinoyldihydrazone(H4CZ)' glutaroyldihydrazone(H4Dz), adipoyldihydrazone(H4Ez)and phthaloyldihydrazone(H~Fz)havebeensynthesizedfrom thereactionof uranylnitratehexahydrateanduranylacetatedihydratewith thetide ligandsin alcoholicmedium.The complexeshavethe compositions[(UOzlz(Hz~XHzOMN03h].2HzO and[(UOzlz(Hz~XCzHsOHlz(CH3COOlz]·CzHsOHwhereH4~=H4Az, H4Bz,H4CZ' H4Dz,H4Ez and H4Fz. The com-plexeshavebeencharacterizedon the basisof elementalanalyses,IDA, DTA, molar conductance,infraredandRamanspectraldata.Metal complexesof acylhydrazoneshavereceivedgreatattentionduringrecentyearsbecauseof theirpharmacologicalapplications1,2, unusualmagneticpropertiesand diverse structuralfeatures3•Al-thoughsomecomplexesof acyldihydrazoneswith3dmetalions4-6 anda few of pyridyldihydrazonecomplexeswith actinides7 have been reported,those of acyldihydrazoneswith actinidesare al-mostnon-existent.This is probablydueto thefactthat in dihydrazonestwo hydrazoneunits arejoinedtogetherthroughmethylenechainsof vary-ing lengthor phenylor pyridylgroupmakingthesystemmorecomplex.Dihydrazones,whichreactin keto (I), keto-enol(IT) and enol (ill) formsde-pendingupon the mode of preparationof thecomplexes,natureof the solvent,the pH of thereactionmedium,thenatureof metalsalt andthemolarratioof thereactants,giveriseto polymericcomplexesthroughboth ligandbridging(becauseof theirflexibility)andoxo-bridging.We reporthere thepreparationand characteriza-tion of dioxouranium(VI)complexeswith somedisalicylaldehydeacylhydrazones(IV).@YY'YOgnV)x=-(CHz),,-n H4~ Ligando H4Az Disalicylaldehydeoxaloyldihydrazone1 H4Bz Disalicylaldehydemalonoyldihydrazone2 H4CZ Disalicylaldehydesuccinoyldihydrazone3 H4Dz Disalicylaldehydeglutaroyldihydrazone4 H4Ez DisalicylaldehydeadipoyldihydrazoneX = - C6H4 - H4Fz DisalicylaldehydephthaloyldihydrazoneMaterialsandMethodsUranyl nitratehexahydrate,uranyl acetatedi-hydrate,diethylestersof oxalic,malonic,succinic,glutaric,adipic and phthalicacids,hydrazinehy-drateand salicylaldehydewereBDH reagentsofAR or equivalentgrade.Acyldihydrazines,viz.,oxaloyl, malonoyl, succinoyl,glutaroyl, adipoylano phthaloyl dihydrazineswere prepared byreactingthe correspondingdiethylesters(1 mol)withhydrazinehydrate(2 mol).The dihydrazoneswere preparedby reactingwarm or refluxingdi-lute solutionsof the aboveacid dihydrazides(1mol) with salicylaldehyde(2 mol) and were col-lectedasdescribedelsewhere8•Uranium in the complexeswas determinedbystandardliteraturemethod9•The ligands in thecomplexeswere determinedin 5M H2S04 withstandardKMn04 usinga calibrationcurve5•Ni-225INDIAN J. CHEM., VOL. 27A,MARCH 1988trogen'lwasdetermined by microanalytical method.Nitratd was determined as nitron nitrate. Waterahd ~anol contents were determined by heatingthe s pIes in an electric oven maintained at 80and 1 .o°C and estimatingthe loss in weight. TheIR sp~tra were recorded in KBr in the range4000-1]80 cm-Ion a Perkin-Elmer-983 spectro-photonl-eter.Raman spectraof (UOzlz(HzAzXN03)Z-6HzO $d (UOzlz(HzAz)(CH3COO }Z3CzHsOHcom-plexes-..tererecordedonaRamanspectrophotometer(Ramalpg 1403) using rotating sampletechnique inorder t~'avoidthedecompositionof thesamples.Themolarc nductancesof thecomplexesat 10- 3Mdilu-tion in anolandDMF weremeasuredusinganEli-cocond ctivityc ll.Thermal studiesof thecomplex swerecafried out in anatmosphereof air,under staticconditi~ns,heatingthespecimenat therateof 1O°C/min in t4erange0-800°C, usingheatedaluminaasthestandar4referencematerial.Prepara~onofthecomplexesThe f~llowinggeneralprocedureswereusedfor theisolatiod of thecomplexes:(i)Ur$tyl nitratehexahydrate(0.1M)wasdissolvedin ethan~l.The ligand(2g),powderedwell in anagatemorter,,+,astakenin 50 ml ethanolandstirredwell togetaho~ogeneousslurry.Uranyl nitratesolutionwasadded to the ligand slurry with gentlestirring main-tainingthemetal:ligandmolar ratio 3:1.The mixturewasrefluxedfor 2hr.In thecaseofH41\andH4Fz,thecomplexesprecipitatedimmediatelybut in the casesofotherligands,asolutionwasobtained.The solution,on concentration( -70 ml) followed by addition ofether, precipitated a semi-solid. This was extractedwith benzeneand stirred well for abouthalf an hourand kept overnight. The complex so obtained waswashedwith ethanol-benzenemixture,benzeneanddried over anhydrouscalcium chloride.(ii)Uranyl acetatedihydratewasdissolvedin etha-nol containingonedrop ofaceticacidtogeta0.1Mso-lution.Any undissolvedmaterialwasfilteredoff.Ura-nylacetatesolutionwasaddedtotheligandslurry(2g)obtainedasabovewith gentlestirringmaintainingthemetal:ligandmolarratioat3:1.The mixedsolution,af-ter refluxingfor one hour, precipitatedthe complexwhich wasisolatedasabove.Results andDiscussionThe resultsof elementalanalyses(Table 1)arecon-sistentwith 2:1 (metal:ligand)stoichiometryand ac-cordingly, the generalformulae (UOz)z(Hz~)(N03)Z6HzO and (UOz)z(Hz~)(CH3COO)z3CzHsOH. Allthecomplexesareamorphouspowders andtheir co-lours vary from dull yellow, yellow, dull orange,.'."tableI-Analytical andMeltingPointDataof Dioxouranium(VI)Complexesof AcyldihydrazonesSINo.Complex ColourFound(Calc.)%(m.p./d.p.,ec) UNLigandN03HzO/CzHsOHi ~(UOz}z( z~)(N03}z6HzOBrown43.017.4729 5110.97.97(>250·)(43.43)(7.66)(29 5(11. 1)(9.85)f2 8238 75-11.27(CH3COO}z3CzHpH(>250·)2 503 218 93 (12.32)3lz(HzBzX )z6HzORedb own69630 8 8•(170)830 45778(UOz)z(HzB )14 999$(CH3COO}z3CzHsOH)1 94 48 17(UOz}Z(H CzXN03}Z6HzO5381 00516 )373203616( lz( zCz) Orange72868-( 2. 2)7D Z zDull orange8~(160)82 10 047l Darkorange0.( 3COO)z3CzHsOH9iE62 6 2982763101(U zl zEz)867 3111( )z(H F )(N03)z6H OY l w50·)6158222 ,z z z yellow729.7(CH3 }z3CzHpH3(·Decompose~226 i ~ l j. II i I I'I"I~' i 11;lill';DAS &LAL: DlOXOURANIUM(VI) COMPLEXES WITH DlSAUCYLAlDEHYDE ACYL HYDRAZONESorange,redbrowntobrown.ThenitratocomplexesoftheligandsH4Bz- H4Ezarepartiallysolubleinetha-no~methanolandacetoneandcompletelysoinDMF,butareinsolublein waterandotherorganicsolventslikeether,chloroform,carbontetrachlorideandben-zene.Acetatocomplexesof theseligandsaresolubleindonorsolventslikeDMF andDMSO only.Thenit-ratocomplexesof H4~ andH4Fz areonlysparinglysolubleinDMF andDMSO whileacetatocomplexesarenotsolubleatall.Themolarconductancesof thenitratocomplexesof H4Bzto H4Ezligandslie in theranges154-190and 145-167ohm-1cmzmol-1 inmethanolandDMF respectivelyindicatingtheir1:2electrolyticbehaviour10•Suchhighvaluesof molarconductancesareduetosolvolysisofthecomplexesincoordinatingsolvents,methanolandDMflI. Themo-larconductancevalues(4.9to15.5ohm-1cmZmol-1)of acetatocomplexesindicatetheirnon-electrolyticnatureinDMflo. Thisis,mostprobably,duetostrongcoordinationbyacetatogroup.Thenitratoandacetatocomplexeshowmasslosscorrespondingto twowaterandoneethanolmole-culesat80°Cindicatingtheirlattice-heldnature.Thecomplexeshowmasslosscorrespondingtofourwa-ter and two ethanolmoleculesat 180°Cindicatingtheircoordinatednature.In thenitratocomplexesofH4Bzto H4EZ'we couldgetsatisfactoryresultsbyheatingthe samplesalthoughtheystartedmelting.The TGA curveof theacetatocomplexNo.6 (seeTable1fornumbering)showsmasslosscorrespond-ing to threeethanolmoleculesin the temperaturerange70-160°Cafterwhich the complexremainsstableup to 300°C.The DTA curveof theacetatocomplexshowsabroadendothermicpeakin there-gion70-220°Cwithaminimumat160°Cgivingaddi-tionalevidenceforthepresenceofethanolmolecules.The lossof oneethanolmoleculein thetemperaturerange70-120°Cindicatesthatit is heldin thelatticewhilethelossoftwoethanolmoleculesinthetempera-turerange120-160°Cindicatesthattheyarecoordi-natedtotheuranylion.Thecomplexstartsdecompos-ingbeyond300°Candattains tabilityinweightafter550°CindicatingtheformationofU30s'DTAcurveshowsthatthecomplexdecomposesin twodistinctsteps,losingtwo CH3CO andtwo - NzHCOCHzgroupsintherange300-380°Candtwophenylringsintherange380-550°C.Comparedtoacetatocomplex(No.6),thenitratocomplex(No.5)givesnoindicationofitsstabilityatanystageoncethedecompositionhascommencedafterlossofcoordinatedwatermoleculesupto250°C.Thedecompositionofthecomplexstartsafter250°Candtwoexothermicpeaksareobservedinthetemperatureranges250-380and380-630°C.TheTGA curveshowslossofweightcorrespondingtotwoandfourwatermoleculesin thetemperatureranges70-120°Cand 120-250°Crespectively.DTA curveshowsoneendothermicpeakfrom70to 120°Candanotherbetween120and250°Ccorrespondingtolat-ticeheldandcoordinatedwatermoleculesrespect-ively.The complexdecomposesabove250°Candshowsmaxima t335and445°Cintheranges250to380°Cand380to630°Cwhichcorrespondstolossoftwonitroandtwo - NzHCOCHz - groupsandtwophenylgroups,respectively.The IR spectraof theligandsshowbandsduetoamideI andC =N stretchingvibrationsin the1700-1600cm-1region.Recently,Paolucci,etaF havere-portedtheexistenceof tautomericketo-enolpheno-menonin thesolidstatein dihydrazonesof pyridinedicarboxylicacidonthebasisof thepresenceof twobandsat -1700and 1685cm-1intheirIR spectra.Inthepresentstudy,wehaveobservedonlyonebandat1666cm-1inthespectrumofH4Ezandat1655cm-1inH4Fz whileintheotherligandstwobandsat - 1674and1666cm-1areobserved.Thepresenceofbandsinthe1674-1655cm-1regionrulesoutthepossibilityoftheexistenceof tautomericketo-enolequilibriainligandsandsuggeststhattheligandsexistprimarilyintheketoform.Thepositionsofthebandsindicatetheinvolvementofintermolecularandintramolecularhy-drogenbonding.TheappearanceofamideI bandataslowpositionas1655cm-1indicatesthatthehydrogenbondingis strongerin ~Fz thanthatin theotherli-gandswhichis alsoconfirmedbytheappearanceofvOHandvNHbandsataslowpositionsas3149cm-1.The amideI bandsof thecomplexes1,3,6 and8showanegativeshiftof12-51edt-I andappearasme-diumtostrongbandsin the1662-1621cm-1 regionindicatingcoordinationoftheligandthrough>C =°grouptotheuranylion.However,theIRspectraoftheothercomplexesin theregion1700-1600cm-1 aredifficultointerpretduetoweakeningofamideI bandandnegativeshiftby about50-60cm-1 in vC =°mode.As a result,amideI bandeitherappearsasashouldertothevC =N bandormergeswithit SimilarobservationshavebeenmadebyIskanderet aL6 inthecopper(ll)andnickel(ll)complexesof someacyldi-hydrazoneligands.Suchanegativeshiftandweaken-ingofamideI bandmaybeattributedtostrongbond-ingbetweenoxygenofcarbonylgroupanduranylion.The complexeshowbandsin the1590-1500em-Iregionwhichmaybe dueto vC - °andamideIImodes.Thebandsin theregion1573-1552cm-1 intheIR spectraoftheligandsundergosplittingandsuf-ferpositiveaswellasnegativeshiftsoncomplexfor-mationandappearinthe1590-1564cm-1and1550-1520cm-1 regionsrespectively.The bandsin the1550-1520cm-1regionareduetothenegativeshiftofamideII bandby2-55cm- 1andthecoordinationof>C =°grouptotheuranylionsuggestingtheexist-227INDIAN J. CHEM., VOL. 27A, MARCH 1988'l--1275s1278s1261m79s5301384s,821w,1746w1261w 655 1411w73 143 5 09sm307m47 09m1283s53 801307wm**, 394m '\ .1283m61w306m66 * ,140 m8 82vs,840w,17 7w53956291 26 *,1702w9 3 s1566m1550m1564s1542s1570s1520m1569s1574m1541w1688m1550m1566s1573s1554s1564s1542m1590s1542s1572s1547s1530s1564s1537s1550s1552s551628s1606s1602s1631s1602s1602s1610s1601s1583s1605s1605s1623s1609s1623s1612s1623s1612s1603m1623s1612s1623s1657m1621s1653m1662m1655s1674s1666s1673s1666s1673s1666s1673s1666s1666s(UQzh(Hz~)(N03-)Z6Hp(UOzlz(Hz~)(CH3COO}z3CzHpH(UOz)z(HzBzXN03h6HzO74932586111210Table2-ImportantSpectralBandsofAcyldihydrazonesandTheirDioxouranium(VI)ComplexesS.No. Ligand/Complex vC=O vC=N AmideIT v(C-O) Anionvibrations+v(C-O)(phenyl)1624s 1572s 1271s1525s1572s 1269s1553s1572s 1270s(UOzlz(HzBz)(CH3COOh3C2HpH(UOz}Z(HzCz)(N03h6HzO(UOzlz(HzCz)(N03}z(CH3COO)z3CzHsOH(UOzlz(HzDz)(N03)z6HzO(UOz)z{HPi)(CH3COO}z3CzHpH(UOzlz(HzEz)(N03}z6HzO(UOzh(HzEz)(CH3COO}Z3CzHsOH(UOzlz(HzFz)(N03)z6Hp(UOz}Z(HzFz)(CH3COO}Z3CzHsOH*Masksligtndsbands;*"overlapswiththeC - °or amideITbandof theligand.Ienceof~ ligandsintheketoform(I)inthecomplexes.ThevCi0 bandispresentin theregion1590-1564cm- 1si~g apositiveshiftbyabout11-35cm- 1,SuchhigItshiftofvC - 0 bandisconsiderediagnos-ticofbintJclearorpolynuclearcomplexesthroughox-obridgin~,The multiplicityof the vC =N bands(1624-16P9cm-1)exhib tedinthelRspectraoftheli-gandis l~stuponcomplexation.Further,theysuffernegativefhift by about10-40cm- 1in all thecom-plexesex~eptin thoseof H4F2complexes.The nega-tiveShift~vC =N bandisattributedtoadecreaseintheJt-bo dcharacterofthe>C =N groupasaresultofnitrog tometalcoordination.Howe r, theIR spectr of theph h lamidocom-plexessh~wapositiveshiftin thevC =N mode.Thisfactcanbeunderstoodintermsofthedrainageoftheelectrondensity,attributedto the replacementofmethylenegroupsbyphenylgroupbetweentwohy-drazoneunits,fromthephenylringofsalicylaldiminegrouptotheuranylionthroughtheazinegroupnitrog-enatomincreasingcarbonandnitrogenbondorderashas been reportedin thiosemicarbazonatocom-plexes12.In other complexesthe drainageof Jt-electrondensityoccursthroughoxygenatoms.Fromtheabovediscussion,itisevidenthattheligandsactasdibasichexadentateandbondtouranylion throughphenolicoxygen,carbonyloxygenandazinegroupni-trogen.On examiningthespectraof theligandsandtheircomplexesbelotv600cm- 1,thenewbandsap-pearingintheranges590-497,496-421and413-300228II II' 1"llillfll' I'!III<IDAS & LAL: DIOXOURANIUM(VI) COMPlEXES WITIi DISAUCYLALDEHYDE ACYL HYDRAZONEScm-1 aretentativelyassignedtov(U- 0)(phenolic),v(U - 0)(carbonyl)andv(U- N) respectively.The IR spectraof alltheuranylcomplexestudiedhereshowstrongabsorptionin theregion938-907em-1 maskingweakto mediumligandbandsandweaktomediumtostrongabsorptioninthe871-851cm-1 regionrespectivelyassignedto v3andVI vibr-ationsoftheuranylgroup.Inuranylcomplexes(UOz)z(Hz~) (N03h6HzO and(UOz)z (Hz~) (CH3COOh3CzHsOH (whereH4~=H4CZ' H4Ez) the assign-mentofvIis alittledoubtfulasbandsofweaktomedi-umintensityoccurin theIR spectraoftheuncoordi-natedligandsalsointhe864-853cm-1region.How-ever,H4Fz complexeshowa strongbandat - 855cm- 1whichcannotbeassignedtoligandbands.Theforbiddenvibrationsmaybecomeallowedasaresultofparticularsymmetryoftheligandfieldaroundura-nylgroupinthecomplexesratherthanslightbendingofthisgroup.TheV3bandinsomecomplexes(Table2)isresolvedintoadoublet1,13-15.TheRamanspectraofthe complexes(UOzh (Hz~) (N03h 6HzO and(UOzh (Hz~) (CH3COOh 3CzHsOHin therange1000-800cm- 1showa strongbandcelltredat864and860 cm-1 respectively,but do not showbandcorrespondingto v3.The doublydegenerateOUObendingmodeisobservedasamediumtostrongbandin the245-212cm-1 regionandit maskstheligandbandsoccurringin thisregion.The IR spectraof the acetatocomplexes howv_COOmodein theregion1412-1391cm-1 andvas_COO modeat 1564-1547cm-1;butin somecom-plexesthelatterbandismaskedbyeitheramidenorvC - 0band.ThepositionsoftheCOO bandsareinagreementwiththebidentatecoordinationofacetatogroupwithuranylion.Keepinginviewthedifferencebetweenthesolubility,decompositiontemperature(meltingpoint)of thenitratoandacetatocomplexesandtheseparation(180-138cm-1)betweenvasCOOandv_COOmodes,thebridgingnatureoftheacetatogroupsismoreprobablein tltepresentcomplexes16.TheIR spectraofthenitratocomplexeshowastrongbandin theregion1392-1384cm-1 (maskingligandband)andaweakbandin theregion853-821cm-1suggestingthatoitratogroupispresenteitherin ionicor weaklycoordinatedform18.The IR spectraof thenitratocomplexesin the region 1800-1700cm-1showcombinationbands(diagnosticofthetypeofnit-rato grouppresent).A singlebandattributableto(VI+v4)modeisobservedwhichindicatesthatstrongcoordinationbynitratogroupisunlikelyl7.Consider-ingthecompositionsofthecomplexes,theirsolubilitybehaviourinthecommonorganicsovlents,highmelt-ing points/decompositionpoints,thedibasichexa-dentatenatureof theligandandthepresenceof oxoandligandbridging,boththenitratoandacetatodiox-)(Y)(YI)ouranium(VI)complexesmaytentativelybeassignedoxo-bridgedpolymericstructures(V andVI) involv-ingninecoordinateuraniumatomReferences1 MerchantJ R & ChothiaD S, J mednlChern,13(1970)335;ReddaK, CoretoL A & KnansE E, J mednlChern,22(1979)1079.2 KatyalM & Dutta'Y,Talanta,22(1975)151.3 NardelliM, PelizziC & PelizziG, TransitionMet Chern,2(1977)35;PelizziC, PelizziG & PredieriG, J organoletalChern,263 (1984)9;LorenziniC, PelizziC, PelizziG &PredieriG, J chemSocDaltonTrans,(1983)721;(1983)2155;Aruffo A A, Murphy T, JohnsonD K, RoseN &SchoemakerM F, inorgchimActa,67 (1982)125.4 Arora D L, Lal K, GuptaSP & SahniSK, IndianJ Chern,24A(1985)980.5 NarangKK.&LalRA, TransitionMetChern,1(1976)260;2(1977)100;3 (1978)272; CU" Sc~46 (1977)401;47(1978)793.6 EI-SayedL & IskanderM F, J inorgnuclChern,38 (1976)2209.7 PaolucciG,StellutoS&SitranS, InorgchimActa,110(1985)19.8 Lal R A, SrivastavaK N & DasS,SynthReactinorgmel-orgChern,(Communicated);Lal R A, DasS& ThapaRK, In-orgchimActa, (Inpress).9 VogelA I, A textbookqfquantitativeinorganicanalysis,(ELBSandLongmans,London),1973.10 GearyW J, CoordChemRev,7 (1971)81.11 LivingstoneS E & OlukaJ E, TransitionMetChern,3 (1978)261;SabaN& BhattacharyaD,IndianJChern,21A(1982)574.12 SaxenaA & TandonJ P,Polyhedron,3 (1984)681.229INDIAN J. CHEM., VOL. 27A, MARCH 1988,13 Bull1kJ I, J ino'Xnuc/Chern,29(1967)2257.14Ho 'gDF,JchemPhys,16(1948)1063;FlintCD&TannerP, Polyhedron,2 (1968)43.15 Pana~oniC, GrazianoR, CroattoD, ZarIiB,BombieriG, In-o~chimActa,2 (1968)623.16 LongjG J, RobinsonW T, ToppmeyerW P &BridgesD L, JclJemSoc,DaltonTrans,(1973)573.230,I I I IIDI' 1'1.11I1117 CurtisNF &CurtisY M,lno'XChern,3(1965)804;LeverABP,MantovaniE&RamaswamyBS, CanJChern,49(1976)1957;SpecaA N, PytleeskiL L, OwensC & Karayamis,Jino'Xnuc/Chern;38(1976)1119.18 Ramakrishnan&SoundarajanS,Mh Chern,107 (1976)1095;VicentiniG &De Oliverra,J ino'Xnuc/Chern,37 (1975)2018.

Synthesis & Characterization of Nitrato & Acetato Complexes of Dioxouranium(VI) with Disalicylaldehyde Acyl Hydrazones

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Synthesis & Characterization of Nitrato & Acetato Complexes of Dioxouranium(VI) with Disalicylaldehyde Acyl Hydrazones

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