Perylene π-Bridges Equally Delocalize Anions and Cations: Proportioned Quinoidal and Aromatic Content

A complete experimental and theoretical study has been carried out for aromatic and quinoidal perylene-based bridges substituted with bis(diarylamine) and bis(arylimine) groups respectively. The through-bridge inter-redox site electronic couplings (V-AB) have been calculated for their respective mixed-valence radical cation and radical anion species. The unusual similitudes of the resulting V-AB values for the given structures reveal the intervention of molecular shapes with balanced semi-quinoidal/semi-aromatic structures in the charge delocalization. An identical molecular object equally responding to the injection of either positive or negative charges is rare in the field of organic pi-conjugated molecules. However, once probed herein for perylene-based systems, it can be extrapolated to other pi-conjugated bridges. As a result, this work opens the door to the rational design of true ambipolar bulk and molecular conductors.