Synthesis, characterization and photoluminescence properties of strong fluorescent BF2 complexes bearing (2-quinolin-2-yl)phenol ligands

Novel N,O bidentate BF2 complexes were prepared in good to excellent yields through the coordination of (2-quinolin-2-yl)phenol and its derivatives with boron trifluoride etherate under mild conditions. These fluorine–boron complexes exhibited strong fluorescence both in organic solvents and in solid state. Their photophysical properties were thoroughly studied by absorption and fluorescence spectroscopy in various solvents. The electronic and site effects of substituents on phenolic and quinolinyl rings were found to have a profound impact on quantum yields. All these complexes were fully characterized by IR, 1H, 13C, 19F NMR and microanalysis. The high quantum yields and large Stokes shifts make these compounds as potential fluorescent dyes.