Synthesis and characterization of 3,4‐diaryl‐substituted polythiophene derivatives

A series of polythiophene derivatives bearing 3,4‐diaryl substituents were synthesized starting from commercially available 3,4‐dibromothiophene. The effects of two different aryl substituents, either a 5‐octyl‐2‐thienyl or a 4‐octylphenyl, were investigated in this study. To minimize steric effects on polymerization and conjugation, polymers were synthesized with a bithiophene or a triple‐bond spacer. The resulting polymers show varying solubility in common organic solvents and their UV‐visible absorption spectra in solution exhibit maxima in the range 434–484 nm, which are significantly red‐shifted as compared to those of 3,4‐dialkyl‐substituted polythiophenes. Gel permeation chromatography analysis using polystyrene standards shows a weight‐average molecular weight range of 1.50 × 10⁴–4.40 × 10⁴ g mol^?1 for the various polymers. Copyright © 2011 Society of Chemical Industry