Design and facile synthesis of quinazolinone-based full color-tunable boron difluoride dyes: Efficient solvent/solid-state emission and bioimaging application

To develop the construction of small organic fluorophores with full color-tunable luminescence through facile synthesis is highly imperative for applications. Herein, novel quinazolinone based BF2 complexes (2a-2g) have been designed and synthesized. By modifying the structure of quinazolinone ligand, the synthesized boron difluoride dyes exhibited fluorescence in the almost full-color range of the visible spectrum (∼450–750 nm) both in solution and solid-state with good to excellent quantum yield. The influence of three electron donating substituents, such as methyl, methoxy and N,N-dimethylamino group, in quinazolinone core on the photophysical properties of BF2 compounds was discussed. The position of substituent in quinazolinone has some influence on the emission efficiency, but has little influence on the absorption and emission of BF2 compounds. Finally, 2g showed good cell compatibility and living cell imaging property.