Synthesis of π-conjugated organoboron polymers by haloboration-phenylboration polymerization of aromatic diynes

Summary

π-Conjugated organoboron polymers were prepared by haloboration-phenylboration polymerization beween diyne monomers and bromodiphenylborane. The polymerization was carried out by adding a slightly excess amount of bromodiphenylborane to a tetrachloroethane solution of diynes at room temperature under nitrogen and stirring the reaction mixture for 4 hours at 100°C. The obtained polymers were soluble in common organic solvents such as THF and chloroform. Their molecular weights were estimated to be several thousands by gel permeation chromatographic analysis. In UV-vis absorption spectra, bathochromic shift of λ_max and absorption edge in comparison with the corresponding monomers were observed, which indicates the π-conjugation via vacant p-orbital of boron atom.