Facile preparation of electrochromic poly(amine-imide) films from diimide compounds with terminal triphenylamino groups via electrochemical oxidative coupling reactions

Two diamide compounds TPABP-DA and TPASO2-DA and two diimide compounds TPA6F-DI and TPASO2-DI with triphenylamine (TPA) end groups were synthesized from the condensation reactions of 4-aminotriphenylamine with respective aromatic dicarboxylic acids and tetracarboxylic dianhydrides. The diimide compounds can be electropolymerized into poly(amine-imide) films on the electrode surface in an electrolyte solution via the coupling reactions between the TPA radical cations. In contrast, electro-oxidation of the diamide analogs produced stable TPA radical cations that did not undergo electropolymerization reactions. The electrogenerated films of TPA6F-DI and TPASO2-DI showed a reversible oxidation redox couple with a half-wave potential ( E 1/2 ) of 0.96 V on their cyclic voltammograms. They exhibited stable electrochromic properties, with coloration change from a colorless neutral state to orange as a radical cation and blue when fully oxidized. Electroactive and electrochromic poly(amine-imide) films could be directly prepared on electrodes from diimide compounds TPA6F-DI and TPASO2-DI with triphenylamino end groups by electrochemical oxidative coupling.