Synthesis of blue light emitting and electrochromic polyimidothioethers with diphenylpyrenylamine chromophore via thiol-ene reaction

Abstract

Two novel blue light emitting and electrochromic polyimidothioethers (PITEs) were prepared from a new diphenylpyrenylamine-based bismaleimide and two commercially available dithiols via the thiol-ene Michael addition polymerization. These two PITEs were readily soluble in various organic solvents and could be cast into robust films on the glass substrate. The PITEs exhibited strong UV–vis absorption bands at 316–319 nm in NMP solution and their photoluminescence spectra showed maximum bands around 473–477 nm in the blue region. The PITE Py-C 2 derived from an aliphatic dithiol of 1,2-ethanedithiol was optically transparent in the visible region and fluoresced with a higher quantum yield (ΦPL = 32 %) compared to that derived from an aromatic dithiol of 4,4’-thiobisbenzenethiol. Cyclic voltammetry studies indicated that they show a moderate stability in the anodic oxidation process, but the cathodic reduction process is irreversible. The PITE films exhibited a noticeable electrochromic behavior, with color change from a colorless neutral state to a purple oxidized state and an orange reduced state.