Preparation, Structure, and Redox Behavior of Bis(diarylmethylene)dihydrothiophene and Its π‑Extended Analogues

The
preparation, X-ray structure, and optoelectronic properties
of bis­(diarylmethylene)­dihydrothiophene 1 and its π-extended
analogues 2 are described. The development of a simple,
short-step synthetic route allowed us to prepare derivatives with
different aryl units. X-ray crystallographic analysis of 1b and 2b revealed their quinoidal structures, which exhibit
strong electronic absorption in the visible region. Cyclic voltammetry
measurements revealed their strong electron-donating properties. 1b showed two-step electrochromic behavior between the corresponding
radical cation and dication.