Substituted poly(p-phenylene)s prepared from 2,5-diheptylbenzene-1,4-bis(trimethylene boronate)

Copolymers were prepared by the Suzuki reaction of 2,5-diheptylbenzene-1,4-bis(trimethylene boronate) with dibromobenzenes or dibromothiophene. From n.m.r. spectra, these copolymers turned out to be alternative copolymers of diheptylbenzene with benzenes or thiophene. The degree of polymerization of poly(2,5-diheptylbenzene) prepared according to the present method was 57, nearly five times as high as that for polymers prepared by Grignard coupling. The copolymer with thiophene had a degree of polymerization as high as 100 and was electrochemically active. Microscopic observation under crossed nicols conditions revealed that spherulite was formed on a film of this copolymer prepared by casting a xylene solution on a glass plate. On an oriented poly(p-phenylene) substrate, poly(p-phenylene-alt-2,5-diheptyl-p-phenylene) chains were aligned along the direction of orientation of the substrate. (C) 1997 Elsevier Science Ltd.