Abstract: The mechanism of electrochemical reactions of electrogenerated Co(Ⅰ)TPP andcyclohexyl bromide was investigated with cyclic voltammetry,in-situ ESR-spectroelec-trpchemistry and insitu micro-electrode-CV thin-layer electrochemistry in DMF solution.The redox reaction of Co(Ⅱ)/Co(Ⅰ) parallelly catalyzed the reduction of cyclohexylbromide,and generated both the cyclohexyl radicals and Co-C bond compound C₆H₁₁Co(Ⅲ)TPP.Further reduction of the Co-C bond compound at-1.30V (SCE) im-plied an EC mechanism,namely electrochemical reduction followed by Co-C bond splittingreaction which regenerated the cyclohexyl radicals with rate constant of 0.73s^-1.The pres-ence of additional CH₂=CHCN led to the generation of a new Co-C bond compound whichgave rise to a reduction peak at -1.10V (SCE).A mechanism for the Co(Ⅱ)TPP/cyclo-hexyl bromide system, suggesting that the cyclohexyl bromide primarily reacts with electro-generated Co(Ⅰ)TPP via the production of the cyclohexyl radicals,has been proposed.

Key words: cobalt tetraphenylporphyrn, electrochemical redox reaction, cyclohexyl bromide, in-situ ESR