Unsaturated polymers containing boron and thiophene units in the backbone

Abstract

2,5-Dialkynylthiophenes (RCC)₂C₄H₂S (R = Ph, Me₃Si or Bu^t) treated successively with HBCl₂ and Et₃SiH in CH₂Cl₂ undergo hydroboration polymerization to give intensely-coloured polymers of general structure –[CHCR–BCl–CRCH–C₄H₂S]_n– for which the ¹¹B NMR resonances occur ca. 50 ppm upfield of those for analogous monomers.