Push–pull type quinoidal perylene showing solvent polarity dependent diradical character and negative solvatochromism

Abstract

Synthesis and physical properties of a new push–pull type quinoidal perylene (DA-Per) are reported. Three resonance forms, a closed-shell quinoid, an open-shell diradicaloid and a closed-shell zwitterion, all contribute to the ground-state electronic structure. The molecule shows solvent polarity dependent diradical character and negative solvatochromism, which can be explained by the subtle balance among the three resonance forms in different solvent environments.