ArCCo~3(CO)~9~-~nL~n的化学ETC合成及其电化学研究

利用由化学还原剂BPK引发的电子迁移催化反应(ETC)合成了两个系列八种新的三核钴簇合物p-RC~6H~4CCo~3(CO)~9~-~nL~n(L=PPh~3, n=1; L=P(OEt)~3, n=2)。用m.p.、元素分析、IR及^1H NMR对簇合物进行了表征。对簇合物在Pt电极上的循环伏安(CV)研究表明, p-RC~6H~4CCo~3(CO)~9及PPh~3单取代物在室温下均经历一个可逆的单电子过程。p-RC~6H~4CCo~3(CO)~9的E~1~/~2与R的σ~m线性关系表明R通过诱导效应影响簇合物的氧化还原性。取代簇合物的还原电势相对于母体簇合物的负转移表明P的配位增大了CCo~3上的电荷密度, 导致簇合物难被还原。

Chemical ETC preparations and electrochemistry of ArCCo~3(CO)~9~-~nL~n

Eight new tricobalt clusters p-RC6H4CCo3(CO))9-nLn (L = PPh3, n = 1; L = P(OEt)3, n = 2; R = Me, MeO, Ac, Br) have been prepared by means of a chem. induced electron-transfer-catalysis reaction. Cyclic voltammetric study of the clusters p-RC6H4CCo3(CO)9-nLn(n = 0, 1, 2) on a Pt electrode in acetone were described. n = 0 And 1 clusters showed a reversible mono-electron process, but n = 2 derivatives showed a quasi-reversible process. A linear relationship between E1/2 of the n = 0 clusters and sm of the R groups indicated that the redox properties of the clusters were affected by the inductive effect of the R group. A cathodic reduction potential shift of L substituted derivatives vs. the parent clusters showed that the coordination of L to Co resulted in an increase of charge d. on the CCo3 unit, which made cluster hard to reduce.