Hyperbranched Poly(2,5-silylthiophenes). The Possibility of σ−π Conjugation in Three Dimensions

New hyperbranched organosilicon polymers have been prepared from 2-bromo-5-(trimethoxysilyl)thiophene. The intermediate alkoxy-substituted hyperbranched polymer is functionalized with Grignard reagents in situ, leading to the isolation of a series of air- and moisture-stable polymers. The polymers contain alternating silylene and thiophene groups along the branches and thus afford the possibility of σ−π conjugation in three dimensions. Investigations into the effects of this dimensionality utilize UV−visible spectroscopy.