Redox behavior of biferrocene dithiol and disulfide derivatives in SAMs with and without gold clusters on the gold substrate

Abstract

1′,1‴-(8,8′-Dithiodioctanoyl)-1,1″-biferrocene (Bfc′S₂) and 1′,1‴-bis(8-mercaptooctanoyl)-1,1″-biferrocene (Bfc′(SH)₂) were synthesized for the purpose of constructing self-assembled monolayers (SAMs) on the gold electrode. These SAMs manifested different structures. The former molecule adsorbed onto the substrate by anchoring its two ends. In contrast, the latter was fixed by only one end, and the other, surplus end was used to anchor the gold cluster to give a SAM with gold clusters. The electrochemical properties of these SAMs were characterized by cyclic voltammetry, which suggested a difference of electronic transference among them. STM images confirmed the array of gold clusters on the surface of the Bfc′(SH)₂-modified gold electrode.