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1、Articlepubs.acs.org/ICSynthesisandCharacterizationofNovelWells−Dawson-TypeMonoVanadium(V)-SubstitutedTungsto-polyoxometalateIsomers:1-and5−4‑[S2VW17O62],††‡††§TadaharuUeda,*MihoOhnishi,MotooShiro,Jun-ichiNambu,ToshiakiYonemura,JohnF.Boas,∥andAlanM.Bond†DepartmentofAppliedScience,FacultyofScienc
2、e,KochiUniversity,Kochi780-8520,Japan‡X-rayResearchLaboratory,RigakuCorporation,Akishima,Tokyo196-8666,Japan§SchoolofPhysics,MonashUniversity,Clayton,Victoria3800,Australia∥SchoolofChemistry,MonashUniversity,Clayton,Victoria3800,Australia*SSupportingInformationABSTRACT:Twovanadium(V)-substitute
3、dtungsto-polyoxo-metalateisomers,1-and4-[SVWO]5−,werepreparedas21762theirtetra-alkylammoniumsaltsfromaWVI−HSO−VV24reactionmixtureinaqueousCH3CNsolution.X-raycrystallo-graphicstructuralanalysisrevealedthatbothisomershaveaWells−Dawson-typestructurewithahigheroccupancyofvanadiumatpolarsitesandbelt
4、sitesfor1-and4-[SVWO]5−,respectively.21762Theisomerswerealsocharacterizedbyelementalanalysis,infrared,Raman,UV−vis,and51VNMRspectroscopiesaswellasvoltammetry,andthedataobtainedwerecomparedwiththatderivedfrom[SWO]4−.Significantly,thereversible21862potentialsforthevanadium(V/IV)coupleforboth1-and4
5、-[SVWO]5−inCHCN(0.1Mn-BuNPF)areconsiderably21762346morepositivethanthetungstatereductionprocessexhibitedbythe[SWO]4−framework,implyingthatthepresenceof21862vanadiumshouldbeusefulincatalyticreactions.Theone-electron-reduced[SVIVWO]6−formsofbothisomerswere21762preparedinsolutionbycontrolledpotent
6、ialbulkelectrolysisandcharacterizedbyvoltammetryandEPRspectroscopy.■INTRODUCTIONtobeexcellentcatalystsforfacilitationofoxidationreactionsin5−11,14organicsyntheses.PolyoxometalateshavebeenextensivelystudiedforalongperiodPolyoxometalatesusuallyalsocontainaheteroioninacentraloftimebecauseoftheirpr
7、acticalapplicationsincatalysis,151−4positionwithintheframework.Themostwidelystudiedonesanalyticalchemistry,biochemistry,andotherfields.Recently,haveusedsilicateorphosphateforthispurpose.Otherheterointerestalsohasbeenfocusedontheiru
