Simple approach to regulate the spectra of novel kinds of polyazomethines containing bulky triphenylamine: Electrochemistry, electrochromism and photophysical responsive to environment

Two series of novel polyazomethines (PAMs) PIa-PIe, PIIa-PIIe were prepared via the direct polycondensation from N,N′-bis(4-aminophenyl)-N,N′- diphenyl-1,4-phenylenediamine, and N,N′-bis(4-aminophenyl)-N,N′- diphenyl-4,4′-biphenyldiamine with various dicarboxaldehyde such as phthaldialdehyde, 1,3-isophthalaldehyde, terephthalaldehyde, 4,4′-diformyltriphenylamine, 5-thiophene-dialdehyde. The variation of the backbone structure significantly affected the dihedral angles and changed the electronic properties of PAMs. The obtained PAMs exhibited stable and reversible electrochromic properties and reversible color change. The color of PAMs could be varied from initial yellowish to red, violet or blue via electrooxidation. And multiple reversible colors states were also observed with pH and chemical doping. Considering the sensitive chromic properties of PAMs, they will have potential applications for display device, chemical sensor, et al.