synthesis, crystal structure and characterization of photochromic

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1、SpectrochimicaActaPartA66(2007)335340Synthesis,crystalstructureandcharacterizationofphotochromic1,2-bis{2-ethyl-5-[2-(1,3-dioxolane)]-3-thienyl}perfluorocyclopenteneShouzhiPua,∗,TiansheYanga,RujiWangb,FushiZhangb,JingkunXuaaJiangxiKeyLabofOrganicChemistry,JiangxiScie

2、nce&TechnologyNormalUniversity,Nanchang330013,ChinabDepartmentofChemistry,TsinghuaUniversity,Beijing100084,ChinaReceived9August2005;receivedinrevisedform17February2006;accepted2March2006AbstractAnovelphotochromicdiarylethene,1,2-bis{2-ethyl-5-[2-(1,3-dioxolane)]-3-t

3、hienyl}perfluorocyclopentene(BEDTP),wassynthesizedanditsstructurewasdeterminedbysingle-crystalX-raydiffractionanalysis.Itsphotochromicandfluorescentpropertieswerealsoinvestigated.Theresultsshowedthatthiscompoundexhibitedreversiblephotochromism,changingfromcolorlesstom

4、agentaafterirradiationwithUVlightbothinsolutionandinthecrystallinephase.Inhexanesolution,theopen-ringisomerofBEDTPexhibitedrelativelystrongfluorescenceat400nmwhenexcitedat282nm.Thefluorescenceintensitydecreasedalongwiththephotochromismuponirradiationwith254nmlightandi

5、tsclosed-ringisomershowedalmostnofluorescence.©2006ElsevierB.V.Allrightsreserved.Keywords:Diarylethene;Crystalstructure;Photochromism;Fluorescence1.Introductionanti-parallelconformerscanundergoeffectivephotocycliza-tionreactionbyaconrotatorymechanismaccordingtothePho

6、tochromismisreferredtoasaphotoisomerizationpro-WoodwardHoffmannrule,whiletheparallelconformersarecessbetweentwoisomershavingdifferentabsorptionspec-photochemicallyinactive[15,16].Thephotogeneratedclosed-tra[1].Generally,photochromiccompoundsareclassifiedintoringisome

7、rsofdiarylethenesshowedsomecolorswithbroadtwocategories,i.e.,thermallyreversiblecompoundsandther-absorptionbandsinthevisibleregion,andtheycouldregen-mallyirreversiblecompounds[2,3].Althoughvarioustypesoferatetheiropen-ringisomersonirradiationwithappropriatephotochro

8、miccompoundshavebeenreportedtodate[46],wavelengthvisiblelight.Theabsorptionmaximaofclosed-ringcompoundsthatundergothermallyirreversiblepho