Benzothiazole-enamide-based BF2 complexes: luminophores exhibiting aggregation-induced emission, tunable emission and highly efficient solid-state emission

A series of benzothiazole-enamide-based boron difluoride complexes (Borebt1-6) were synthesized and characterized. These new luminophores were demonstrated to possess aggregation-induced emission, tunable, substituent-dependent emission profiles and large Stokes shift in solution. In the solid state, Borebt1-6 exhibited intense emission with high quantum yields of 0.21-0.37. The photophysical properties and AIE characteristics of these compounds were rationalized through X-ray crystal analysis, electrochemical studies and theoretical calculations. Furthermore, Borebt3-6 were capable of sensing acidic gas by reversible changes of emission, which may potentially serve as solid-state fluorescent sensors for acidic vapors.