SYNTHESIS AND CHEMICAL PROPERTIES OF POLY(ARYLENEETHYNYLENE)S WITH AN OLIGO(p-PHENYLENE) GROUP AT m-PHENYLENE LINKAGE

The Pd-complex-catalyzed polymerization of 2,7-dibromo-9,9-dihexylfluorene, 2,5-dibromo-3-hexylthiophene, and 1,4-dibromo-2,5-dioctyloxybenzene with 3,5-diethynyl-4-methoxy[1,1';4',1'']terphenyl afforded poly(aryleneethynylene)s (PAEs), Polymer-1, Polymer-2, and Polymer-3, respectively; the Pd-complexcatalyzed polymerization of the same with 1,3-diethynylbenzene afforded PAEs, Polymer-4, Polymer-5, and Polymer-6, respectively. A model compound, Model-1, was synthesized by the reaction of 3,5-dibromo-4-methoxy[1,1';4',1'']terphenyl with ethynylbenzene in a 1:2 molar ratio. UV-vis measurements revealed that the π conjugation system of the polymer chain is interrupted at the m-phenylene group. The polymers and the model compound were photoluminescent in solution. The polymers received electrochemical oxidation in film; these polymers exhibited electrochromism and showed good thermal stability.