Pure-color and dual-color emission from BODIPY homopolymers containing the cardo boron structure
Versatile luminescent properties such as pure-color and dual-color emission are reported with homopolymers composed of modified boron dipyrromethene (BODIPY) involving cardo boron. By linking phenyl groups to the boron atom, the cardo structure was constructed on BODIPY, and the homopolymer was prepared via oxidation coupling. From the emission measurements, it was found that the emission band was obtained from the phenyl-bearing homopolymer in the longer wavelength region than that of the small molecule. In particular, pure-color emission, which can be represented by the narrow peak width at half height, was obtained from the polymer. Next, we modified the cardo structure with anthracene units. Optical measurements revealed that the polymer provided dual emission bands from the anthracene unit and the polymer main-chain simultaneously in the emission spectrum. It was implied that molecular motions in the excited state could be suppressed at the cardo boron in the polymer. Thus, such unique and useful luminescent behaviors were obtained from conjugated polymers.