Synthesis of new main-chain-type organoboron quinolate polymer linked on quinolate ligand

A main-chain-type organoboron quinolate polymer was prepared by means of polymer reaction between the precursor polymer and triphenylborane. The precursor polymer was synthesized by the Sonogashira-Hagihara coupling reaction between diyne monomer and tert-butoxycarbonyl- (Boc-) protected dibromoquinolinol monomer. The polymer reactions we carried out were successfully achieved and the structures of the obtained polymers were confirmed by IR, H-1 NMR, and elemental analyses. The precursor polymers showed blue or green emissions. In contrast, the organoboron quinolate polymer exhibited dramatically red-shifted orange photoluminescence. The quantum yield of the organoboron quinolate polymer was not significantly high. However, the molar extinction coefficient of the polymer at the excitation wavelength was remarkably improved by incorporation of the quinolate structure into the conjugated polymer main-chain. It was suggested that the conjugated main-chain behaved as a light harvesting antenna for organoboron quinolate units.