Abstract: | A new thiol-derivatized metalloporphyrin, 5-{3-methoxyl-4-(4-mercaptobutoxy)}phenyl-10,15,20-triphenylporphyrincobalt (MBPPCo), has been synthesized. The electrochemical behavior of unitary or binary self-assembled monolayers (SAMs) of MBPPCo and thiols with carboxylic terminal groups was investigated using Fe(CN)6 3−/4− and ascorbic acid (AA) as probe species. The binary modified electrode showed a small increase in peak current but a large decrease in overpotential. However, in anionic electroactive species [Fe(CN)6 3−/4− or AA], either positively charged MBPPCo or negatively charged thiol SAMs solely, slow electron transfer kinetics was obtained and the possible reasons for the discrepancy are discussed. |