Fluorescent and electrochromic aromatic polyamides with 4-tert-butyltriphenylamine chromophore

Abstract

A new triphenylamine-based aromatic dicarboxylic acid monomer, 4-tert-butyl-4′,4″-dicarboxytriphenylamine (2), was synthesized from the cesium fluoride mediated N,N-diarylation reaction of 4-tert-butylaniline with 4-fluorobenzonitrile and subsequent alkaline hydrolysis of the dinitrile intermediate. A series of six aromatic polyamides 4a-4f with tert-butyltriphenylamine groups was prepared from the newly synthesized dicarboxylic acid and various aromatic diamines. These polyamides were readily soluble in many organic solvents and could be solution-cast into flexible and strong films. The glass-transition temperatures of these polymers were in the range of 274–311 °C. These polymers exhibited strong UV-vis absorption bands at 356–366 nm in NMP solution. Their photoluminescence spectra showed maximum bands around 433–466 nm in the blue region. Cyclic voltammograms of all the polyamides exhibited reversible oxidation redox couples in acetonitrile. The polyamide 4f, with tert-butyltriphenylamine segment in both diacid and diamine residues, exhibited stable electrochromic characteristics with a color change from a colorless neutral form, through a green semioxidized form, to a deep purple fully oxidized form. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2798–2809, 2010