α,α′-Diamino-<i>p</i>-quinodimethanes with Three Stable Oxidation States

Abstract

Herein, we report the rational design, synthesis, and characterization of α,α'-diamino-substituted-<i>p</i>-quinodimethanes, which are a group of partially substituted <i>p</i>-quinodimethanes. These exhibit two reversible one-electron redox steps and electrochromism in the ultraviolet, visible, and near-infrared regions. We were able to isolate the crystalline compounds of all three oxidation states: neutral, radical cation, and dication. The obtained results not only create the bridge between <i>p</i>-quinodimethane and α,α,α',α'-tetrasubstituted-<i>p</i>-quinodimethane, but also demonstrate the straightforward modular approach for the synthesis of π-conjugated open-shell compounds.