Monomers of 3-alkyl-substituted thiophene: synthetic routes for the functionalization with non-linear optical chromophores

Synthetic methods for the functionalization of alkylthiophenes with stilbenic and azobenzenic chromophores were successfully explored starting from 3-(ω-bromoalkyl)thiophenes as the main intermediates. The incorporation of the chromophores was achieved through ethereal and aminic linkages obtained by nucleophilic substitution under different experimental conditions. These methods permitted to synthesize a number of alkylthiophenic monomers functionalized at the end of the side chain with second-order non-linear optical chromophores. Some of the new monomers were chemically polymerized.