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 dibromothiophe ne. 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 t he present method was 57, nearly five times as high as that for polyme rs prepared by Grignard coupling. The copolymer with thiophene had a d egree of polymerization as high as 100 and was electrochemically activ e. Microscopic observation under crossed nicols conditions revealed th at spherulite was formed on a film of this copolymer prepared by casti ng a xylene solution on a glass plate. On an oriented poly(p-phenylene ) substrate, poly(p-phenylene-alt-2,5-diheptyl-p-phenylene) chains wer e aligned along the direction of orientation of the substrate. (C) 199 7 Elsevier Science Ltd.