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

1 ' ,1 ' ' '-(8,8 ' -Dithiodioctanoyl)-1,1 " -biferrocene (Bfc 'S-2) and 1 ' ,1 ' ' ' -bis(8-mercaptooctanoyl)-1,1 " -biferrocene (Bfc ' (SH)(2)) were synthesized for the purpose of constructing self-assembled monolayers (SAM s) on the gold electrode. These SAMs manifested different structures. The f ormer molecule adsorbed onto the substrate by anchoring its two ends. In co ntrast, the latter was fixed by only one end, and the other, surplus end wa s used to anchor the gold cluster to give a SAM with gold clusters. The ele ctrochemical properties of these SAMs were characterized by cyclic voltamme try, which suggested a difference of electronic transference among them. ST M images confirmed the array of gold clusters on the surface of the Bfc ' ( SH)(2)-modified gold electrode.