Synthesis and Electronic Structure of Dicyanofulvene-Fused Electron Accepting Molecule Based on a 1,5-Dihydro‑<i>s</i>‑Indacene Framework

A novel dicyanofulvene dimer fused to a benzene ring (3a) has been synthesized as an electron-accepting molecule. The low-lying LUMO level was validated by measuring the ultraviolet photoelectron spectroscopy and electronic spectra. Cyclic voltammetry exhibited sequential reversible waves from 3a to 3a4– in a range of −0.30 to −2.14 V (vs Fc/Fc+). The electronic structure of 3a and its anionic species (3a•–, 3a2–, 3a3•–, and 3a4–) were investigated by electronic spectra and X-ray crystallographic analyses.