Oxidation of Ferrocenyl End-Substituted Oligothiophenes

A ferrocenyl end-substituted terthiophenes derivative and a sexithiophene derivative were prepared as model compounds for a molecular wire. Electrochemical measurements and absorption spectroscopy were performed to elucidate the oxidation process and the oxidized states of those model compounds. The first oxidation of the model compounds took place in the ferrocene moieties (terminals). The resultant oxidized species in the ferrocene moieties seeped into the oligothiophene moieties (wires) and spread over two or three thiophene rings. Further oxidation of the ferrocenyl-terthiophene derivative did not occur, whereas that of the ferrocenyl-sexithiophene derivative produced an oxidized species, such as a cation radical in the sexithiophene moiety.