Synthesis, structure, and both cathodic and anodic reversible redox reactions of benzochalcogenophenes containing ferrocene units

2,3-Diferrocenylbenzo[b]thiophene and 1,3-diferrocenylbenzo[c]thiophene have been systematically and selectively synthesized from benzo[b]thiophene and phthaloyl dichloride, respectively. Characterization of the molecules was performed by physical and spectroscopic means and X-ray crystallographic analyses. The cyclic voltammograms of the novel thiophene derivatives containing ferrocene fragments showed a well-defined reversible cathodic step derived from the unusually stable thiophene radical anions and two distinct reversible anodic steps derived from ferrocenium cations separated from each other by a thiophene heterocycle. 1,3-Diferrocenylbenzo[c]selenophene was also synthesized in a similar manner for formation of 1,3-diferrocenylbenzo[c]thiophene by the use of bis(dimethylaluminum) selenide as a selenating reagent.