Pyrenylamine‐functionalized aromatic polyamides as efficient blue‐emitters and multicolored electrochromic materials

A series of novel aromatic polyamides with pyrenylamine in the backbone were prepared from a newly synthesized dicarboxylic acid monomer, N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene, and various aromatic diamines via the phosphorylation polyamidation technique. These polyamides were readily soluble in many organic solvents and could be solution‐cast into tough and amorphous films. They had useful levels of thermal stability with glass‐transition temperatures in the range of 276–342 °C and 10% weight loss temperatures in excess of 500 °C. The dilute N‐methyl‐2‐pyrrolidone (NMP) solutions of these polymers exhibited fluorescence maxima around 455–540 nm with quantum yields up to 56.9%. The polyamides also showed remarkable solvatochromism of the emission spectra. Their films showed reversible electrochemical oxidation and reduction accompanied by strong color changes from colorless neutral state to purple oxidized state and to yellow reduced state. The polyamide 4g containing the pyrenylamine units in both diacid and diamine sides exhibited easily accessible p‐ and n‐doped states, together with multicolored electrochromic behaviors. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011