Synthesis and optical properties of organosilicon–oligothiophene branched polymers

Star-shaped monomers bearing three bromobithiophenyl units linked by an organosilicon core were polymerized with 1:1 mixtures of (tributylstannyl)hexylterthiophene and bis[(tributylstannyl)thienyl]arenes under the Stille coupling conditions leading to the formation of the corresponding branched polymers bearing quinquethiophenyl side groups and an Si-linked bis(bithiophenylene)arylene backbone as yellow–dark brown and red solids that are soluble in organic solvents, such as chloroform and THF. Optical properties of the resulting polymers were investigated with respect to the UV–vis absorption and photoluminescence spectra, suggesting the efficient energy transfer between the π-conjugated systems at the photo-excited states. Semi-conducting properties of the polymer films were also investigated.