Synthesis of π-Conjugated Materiarls Based on Carboranes
Carborane(C2B10H12) is a polyhedral carbon and boron cluster compound, which has unique properties such as neutron capturing ability based on boron atom, strong electron-withdrawing capacity, and thermal as well as chemical stability. We have recently focused on the development of π-conjugated compounds and polymers that contain 1,2-disubstituted o-carborane units.
π-Conjugated molecules and polymers with the 1,2-disubstituted o-carborane units show aggregation-induced emission (AIE) properties. In solution, intramolecular charge transfer (ICT) from the π-conjugated moieties to the C1-C2 bond of o-carborane quenches the emission; in contrast, in the aggregation state, freezing of the molecular motion suppresses the vibrational radiation and allows the emission. The o-carborane dyes are expected to be applied to light-emitting devices.
Benzocarborane is one of derivatives of o-carborane, in which a benzene ring and the carbon-carbon bond of o-carborane are fused to form a benzenoid ring structure on the carborane cage. We reported the π-conjugated polymer having benzocarborane units and aromatic rings-fused benzocarborane. Because of the highly planar π-conjugated moiety, benzocarborane is a good candidate for the optical and electronic materials utilizing carborane properties.