On the structural and electronic properties of poly(3-thiophen-3-yl-acrylic acid methyl ester)

Quantum chemical calculations on small idealized systems of poly(3-thiophen-3-yl-acrylic acid methyl ester), a new polythiophene derivative soluble in polar solvents, have been performed to propose a model for this polymer. The model, which was derived from calculations at the HF/6-31G(d) and B3PW91/6-31+G(d,p) levels is defined by both the head-to-tail polymer linkages and the conformation of the acrylic acid methyl ester side groups. The π–π∗ lowest transition energy predicted for the polymer is in excellent agreement with the experimental values, which were determined in this work using UV–visible experiments. Finally, we investigated the variation of the electronic properties produced by small chemical modifications in the side group of poly(3-thiophen-3-yl-acrylic acid methyl ester), such changes being designed to enhance the solubility of the polymer in water.