Advances in Ni(0)-Catalyzed Coupling for the Synthesis of Polythiophenes and Polyphenylenes

Abstract

The effects of solvent and monomer structure on the Ni(0)-catalyzed polymerization of 2,5-dichloro-3-(2‘-thiophenecarbonyl)thiophene, 3-benzenesulfonyl-2,5-dichlorothiophene, 2,5-dichlorobenzophenone, and 2-benzenesulfonyl-1,4-dichlorobenzene were explored. Poly[3-(2‘-thiophenecarbonyl)-2,5-thiophene] with an intrinsic viscosity of 0.38 dL/g and a 10% weight loss temperature in nitrogen of 480 °C (Tg = 149 °C) was synthesized. Oligomeric material was prepared from 3-benzenesulfonyl-2,5-dichlorothiophene. Poly(2,5-benzophenone) of 58 × 103 g/mol ([η] = 1.15 dL/g) with a Tg of 180 °C and a 10% weight loss temperature in nitrogen of 576 °C was synthesized. Oligomeric materials were also obtained from the polymerization of 2-benzenesulfonyl-1,4-dichlorobenzene. It was shown that the solvent choice has drastic effects upon the catalyst system and the final polymer. The differences in the catalyst resulting from solvent choice were explored by nuclear magnetic resonance. Effects arising from the structure of the monomer are discussed in relationship to the results obtained and the proposed mechanism.