Synthesis and property of helical ladder polymer comprising of fuzed benzothofhene ring

Thiaheterohelicenes have been often characterized by unique optical activity and stable doped state due to their π-electron-excess conjugation on the thiophene ring. Quantitative oxidation of the methylthio-substituted poly(1,3-phenylene) afforded the precursor polymer. The following intramolecular condensation gave the corresponding helical polymer comprised of fused benzothiophene unit without any structural defects. The MCD absorptions of the polythiaheterohelicene at 298 nm and 342 nm were assigned to the π-π* transition and an original energy transition of the fused ring structure respectively. The electronic state of doped polymer will be also discussed.