Reactions between 1‐Ethynylazulenes and 7,7,8,8‐Tetracyanoquinodimethane (TCNQ): Preparation, Properties, and Redox Behavior of Novel Azulene‐Substituted Redox‐Active Chromophores

Abstract

Abstract [2+2] Cycloaddition/cycloreversion reactions between TCNQ and mono‐ or bis[2‐(azulen‐1‐yl)ethynyl]benzene or ‐thiophene derivatives were examined: the corresponding TCNQ adducts, novel azulene‐substituted redox‐active chromophores, were produced in excellent yields. TCNE/TCNQ double adducts were also prepared both by stepwise and by one‐pot cascade reactions. The redox behavior of these novel azulene‐substituted chromophores was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Significant color changes in these azulene‐substituted chromophores under electrochemical reduction conditions were observed by visible spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)