The Synthesis and Characterization of Highly Fluorescent Polycyclic Azaborine Chromophores.

Six new heteroaromatic polycyclic azaborine chromophores were designed, synthesized, and investigated as easily tunable high-luminescent organic materials. The impact of the nitrogen-boron-hydroxy (N-BOH) unit in the azaborines was investigated by comparison with their N-carbonyl analogs. Insertion of the N-B(OH)-C unit into heteroaromatic polycyclic compounds resulted in strong visible absorption and sharp fluorescence with efficient quantum yields. The solid-state fluorescence of the heteroaromatic polycyclic compounds displayed a large Stokes shift compared to being in solution. The large Stokes shifts observed offset the self-quench effect in the solid state.