Preparation, characterization and spectroscopic properties of difluoroboron complexes with some fluoroquinolones

•Preparation and characterization of difluoroboron complexes with fluoroquinolones.•Spectroscopic properties of difluoroboron complexes.•Fluorescence behavior and quantum yields for difluoroboron complexes.

Six novel difluoroboron complexes with fluoroquinolones were prepared from fluoroquinolones via complexation with boron trifluoride etherate in DMF–CH2Cl2 solution. Their spectroscopic properties were investigated by UV–vis absorption, FTIR, 1H NMR and fluorescence spectroscopic techniques. The results showed that these difluoroboron complexes exhibited the intense fluorescence emission at 401–579 nm under UV visible illumination and possessed a relatively high quantum yield in DMSO solution and solid state. Especially, the difluoroboron complex of Levofloxacin displayed the strongest fluorescence and highest quantum yield (Φu = 0.63) in these difluoroboron complexes, due to its conjugated rigid plane system via four fused six-membered cyclic structures.

Graphical abstractSix novel difluoroboron complexes with fluoroquinolones were prepared from fluoroquinolones via complexation with boron trifluoride etherate in DMF–CH2Cl2 solution. Their structures were characterized by FT-IR, 1H NMR, mass spectrometry and elemental analysis. Their fluorescent properties were investigated in DMSO by UV–vis absorption and fluorescence spectroscopy.Figure optionsDownload full-size imageDownload as PowerPoint slide