Electrochromic conjugated N-salicylidene-aniline (anil) functionalized pyrrole and 2,5-dithienylpyrrole-based polymers

Abstract

Here we describe the first report of a family of fully conjugated monomers bearing salicylidene-aniline (anil) photochromes as pendant functional groups. These monomers are either N-functionalized pyrroles or 2,5-dithienylpyrroles. While the pyrrole monomers are not found to electropolymerize, the 2,5-dithienylpyrrole monomers electropolymerize to yield electroactive films, with well-behaved electrochemical properties. Additionally, the polymer films are found to be electrochromic, changing from yellow in the neutral form, to a light green intermediate state at low levels of oxidation, and finally to a dark gray-blue upon oxidation. A photochromic response associated with the light induced tautomerization of the anil functionality is observed in powder form for two of the monomers, although no photochromic response is observed for the polymers in thin film form. Some NLO properties of the monomers are reported as well.