Charge Transfer Properties of Benzo[b]thiophene Ferrocenyl Complexes
journal contributionposted on 28.09.2015, 00:00 by Alessandro Donoli, Annalisa Bisello, Roberta Cardena, Marco Crisma, Laura Orian, Saverio Santi
The synthesis of 2-ferrocenylbenzo[b]thiophene, 3-ferrocenylbenzo[b]thiophene, 1,1′-bis(2-indene)ferrocene, and the two isomers of 1,1′-bis(2-benzo[b]thiophene)ferrocene was efficiently achieved by using the palladium-catalyzed Negishi C,C cross-coupling reaction of the appropriate bromobenzo[b]thiophene derivative with ferrocenylzinc chloride. The accessibility of differently substituted benzo[b]thiophenes and a comparison with indene analogues allowed an in-depth investigation on how the geometric modifications and the presence of sulfur affect their physical properties. The molecular structure of 3-ferrocenylbenzo[b]thiophene has been determined by X-ray diffraction. Electrochemistry and UV–vis–NIR spectroscopy, in particular the appearance upon oxidation of a charge transfer absorption in the NIR region, are rationalized through quantum chemistry calculations and in the framework of the Hush theory.