Spectroscopic and Spectroelectrochemical Properties of a Poly(alkylthiophene)−Oligoaniline Hybrid Polymer

Abstract

By copolymerization of 3-octylthiophene with thiophene containing aniline tetramer in the 3-position we have prepared a hybrid copolymer, poly(3-octyl-2,5-thienylene-co-3-oligoaniline-2,5-thienylene), exhibiting very interesting spectroscopic and spectroelectrochemical properties. The UV−vis−NIR spectrum of this new hybrid copolymer, in addition to the band ascribed to the π−π* transition in the poly(2,5-thienylene) chain, shows two bands at 330 nm and ca. 580 nm which can be attributed to the transitions in the pendant oligoaniline groups, namely to the π−π* transition in the benzoid ring and to the excitonic-type transition between the HOMO orbital of the benzoid ring and the LUMO orbital of the quinoid ring. Electrochemical activity of poly(3-octyl-2,5-thienylene-co-3-oligoaniline-2,5-thienylene) was tested in nonaqueous electrolytes combining cyclic voltammetry, UV−vis−NIR spectroelectrochemistry, and Raman spectroelectrochemistry. All techniques unequivocally show that both the oligoaniline side chai...