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.

Key words: MOLECULAR STRUCTURE, CLUSTER COMPOUND, COBALT COMPLEX, ELECTROCHEMICAL REACTION, CHARACTERIZATION, CYCLOVOLTAMGRAPH, CATALYTIC REACTION, DIPHENYLMETHANONE, FREE RADICALS, ELECTRONIC MIGRATION