Alternating Fluorene-di(thiophene)quinoxaline Copolymers via Microwave-Supported Suzuki Cross-Coupling Reactions

Three different acceptor moieties, 2,3-di-n-octyl-5,8-bis(5-bromothiophene-2-yl)quinoxaline, 2,3-bis(4'-tert-butylbiphenyl-4-yl)-5,8-bis(5-bromothiophene-2-yl)quinoxaline, and 2,3-bis(4'-n-octylbiphenyl-4-yl)-5,8-bis(5-bromothiophene-2-yl) quinoxaline, have been designed und synthesized utilizing Suzuki cross-couplings. Subsequently, these acceptor units have been connected to thiophene donor units by Stille cross-couplings, resulting in three novel donor-acceptor-donor moieties. In addition, alternating copolymers of these donor-acceptor-donor building blocks with fluorene units have been prepared by microwave-supported Suzuki cross-couplings. The materials have been fully characterized and the optical properties have been analyzed. Single-layer polymer red-light-emitting diodes have been prepared by blending 3 wt % of the alternating copolymers with poly(9,9'-(bis(n-octyl)fluorene-cobenzothiadiazole), revealing efficiencies ranging from 0.19 to 0.75 cd/A. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7794-7808, 2008