Synthesis, Properties, and Redox Behavior of Ferrocenyl-1,1,4,4-tetracyano-1,3-butadienes Connected by Arylamine and Azobenzene Spacers

Abstract

Abstract Ferrocene-substituted 1,1,4,4-tetracyano-1,3-butadienes (FcTCBDs) connected by arylamine and azobenzene spacers were prepared by the reaction of a variety of alkynes with tetracyanoethylene (TCNE) in a [2 + 2] cycloaddition, followed by retroelectrocyclization of the initially formed [2 + 2] cycloadducts (i.e., cyclobutene derivatives). The characteristic intramolecular charge transfer (ICT) from the donors (ferrocene and arylamine) to the acceptor (TCBD) moieties was investigated by using UV–vis spectroscopy. The redox behaviors of the FcTCBDs were examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed their promising redox properties with multi-electron transfer depending on the number of FcTCBD moieties in the molecules. Moreover, significant color changes were observed by visible spectroscopy under the electrochemical reduction conditions.