室温下吡啶溶液中的富勒稀荧光研究(英文)

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【关键词】C60 荧光 吡啶 相互作用 

【出版日期】2005-03-30

【摘要】室温下,在C6 0 -吡啶溶液中观察到了3 99nm到75 0nm范围内C6 0 丰富的荧光峰。C6 0 和吡啶之间的相互作用,破坏了C6 0 分子的高度对称性,从而放松了选择定则,使得荧光辐射率增强。这种相互作用也被C6 0 -吡啶溶液中C6 0 的电化学还原和表面增强拉曼散射证实。

【刊名】光散射学报

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ThefluorescencequantumyieldofC60 isverylow [1 ] Therefore ,itisdifficulttoobservestrongfluo rescenceofisolatedC60 atnormalexperimentalconditions However ,theenvironmentaleffects,theraregasmatrixperturbationeffectandthelow -tempera tureeffect,forexample ,couldrelaxtheselectionrulesofC60 andleadtoahighfluorescenceradiationrate [2 - 3] Accordingtotheoreticalcalculations ,thelowestunoccupiedmolecularorbitalinC60 isthree -folddegenerate Hence ,C60 couldbeabletoacceptuptosixelectronsduringreduction ,asaneffectiveelectronacceptor Withtheelectrondonor ,thepossibleformationofadductbycharge -transfercouldlowertheicosahedralsymmetryofC60 molecule ,leadingtotheobservationofstrongfluorescenceofC60 Inthispaperwell-resolvedstrongfluorescencepeaksforC60 dissolvedinpyridineintherangefrom399nmto 75 0nmatroomtemperaturearereported TheseindicatethatC60 hasimportantopticalprop ertiesandgreatpotentialofbeinganew photosensitiveandluminescentmaterial.Fig 1exhibitsthefluorescencespectrumofC60 inC60 - pyridinesolution ,excitedat 380nm Therearethreebroadregionsoffluorescencebands ,centeredat 42 5nm ,5 75nmand 70 0nm ,respective ly Amongthethreeregions ,thewidebandcenteredat 42 5nmincludesfourweakpeaks:399nm ,42 1nm ,435nmand 465nm Thebandcenteredat 70 0nmisdividedintoseveralsharppeakstoo . Fig .1 ThefluorescencespectrumofC6 0 inC6 0 -pyri dinesolutionatroomtemperaturewithexcitationat 3 80nm  Fig .2 CyclicvoltammogramforthereductionofC6 0inpyridinecontaining 0 .1M (TBA)ClO4 asasupportingelectrolyteatroomtemperature Fig .3 RamanandSERSspectraofC6 0 .(a)SERSspectrumofC6 0 fromC6 0 -pyridinesolutionmixedwithgoldhy drosol;(b)RamanspectrumoforiginalpuresolidC6 0 ;(c)RamanspectrumofC6 0 solidseparatedoutfromC6 0 -pyridinesolution .Itismostlikelythatthishigh - qualityfluorescencespectrumshouldbeattributedtotheinteractionbetweenpyridineandC60 Thisinteractioncouldbefurtherdemonstratedbythefollowingdifferentex perimentalobservationsThreereductionpeaksofC60 areobservedasshowninfig 2 ,whichindicatesthatchargetransferhasoccurredbetweenC60 and pyridine ,namely ,C60 moleculescaptureelectronsfrom pyridinemolecules Similartothefullerenes /N ,N -Diethylanilinecharge -transfercomplex ,itislikelythatC60andpyridineformanadductthroughchargetransfer Surface -enhancedRamanscattering (SERS)spectrumofC60 ingoldhydrosol,asindicatedinFig 3(a) ,alsoilluminatetheformationofC60 - pyridineadduct Asiswell-known ,C60 haslowsolubil ityinaqueousgoldenhydrosolandlowconcentrationinthemixedC60 - pyridinesolution However,theSERSspectrumwithenhancementfactorof 8× 1 0 4showsthatmanyC60 moleculeshavesuccessfullyat tachedtothesurfaceofgoldparticles ItisnotablethatthereismainlyweakphysicalinteractionbetweenC60 andpyridineintheC60 - pyridineadduct ThemixedC60 - pyridinesolutionwasdroppedontothecleanglass,thenpyridineevaporateduntilC60 wasseparatedoutandcrystallizedintosolid TheRamanspectrumofcrystallizedC60 ontheglassinFig 3(c)showsthesameresultasthatoforiginalpureC60solidinFig 3(b) ,whichsuggeststhatC60 moleculeremainsthecompletefullerenestructureastheorigi nalpureC60 solidafterbeingseparatedoutfromthepyridinesolution Therefore ,C60 moleculeprobablymakesonlyaweakphysicalinteractionwithpyridineanddoesnotsubstantivelyreactchemicallywithpyridine 室温下吡啶溶液中的富勒稀荧光研究(英文)C60;;荧光;;吡啶;;相互作用室温下,在C6 0 -吡啶溶液中观察到了3 99nm到75 0nm范围内C6 0 丰富的荧光峰。C6 0 和吡啶之间的相互作用,破坏了C6 0 分子的高度对称性,从而放松了选择定则,使得荧光辐射率增强。这种相互作用也被C6 0 -吡啶溶液中C6 0 的电化学还原和表面增强拉曼散射证实。[1] Ma,B ,Sun,Y -P J ChemSocPerkinTrans1996,2:2157 [2] Wang,Y J PhysChem,1992,96:764 [3] SunY P ,WangP .,HamiltonN B J AmChemSoc,1993,115:6378.

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