A series of polyaromatic hydrocarbons conjugated viologens: synthesis, supramolecular structures in solid state, and electrochemical and photophysical properties

Abstract

Viologens have extensive applications in supramolecular chemistry and materials science. An efficient approach to tune the electrochemical and photophysical properties as well as supramolecular interactions of a viologen unit is to extend its conjugation extent. In this article, a series of conjugated viologens have been designed and synthesized by incorporating polyaromatic hydrocarbons into 4,4′-bipyridyl unit. X-ray crystallographic analyses revealed that they assembled into various supramolecular structures in solid state. Cyclic voltammetry, and UV–vis and fluorescence spectroscopy studies indicated that they displayed distinctive electrochemical and photophysical properties, which were different from non-conjugated viologens. Furthermore, a correlation between reduction potentials and the dihedral angles between bipyridyl unit and polyaromatic moieties was also revealed.