Synthesis and Properties of Conjugated Polymers Containing 3,9-and 2,9-Linked Carbazole Units in the Main Chain

Novel conjugated polymers containing 3,9- or 2,9-linked carbazole units in the main chain were synthesized by the polycondensation of ethynyl- and iodo-substituted 9-arylenecarbazolylene monomers, and their optical and electrical properties were studied. Polymers with weight-average molecular weights of 3400-12,000 were obtained in 76-99% yields by the Sonogashira coupling polycondensation in piperidine or tetrahydrofuran (THF)/piperidine at 30 degrees C for 48 h. All the 3,9-linked polymers absorbed light around 300 nm. The para-phenylene-linked polymer also absorbed light around 350 nm, while meta-phenylene-linked one did not. The 3,9-linked polymers absorbed light at a wavelength longer than the 2,9-linked one. The polymers emitted blue fluorescence with high quantum yields (0.21-0.78) upon excitation at the absorption maxima. The polymers were oxidized around 0.6 V, and reduced around 0.5 V Poly(1) showed the dark conductivity of 3.7 x 10(-11) S/cm (10(3) V/cm). (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3506-3517, 2009