Effect of solvent nature on spectral properties of blue-emitting meso-propargylamino-BODIPY

The spectral and luminescent properties of meso -propargylamino-boron (III) dipyrromethenate (BODIPY 1 ) were studied in a wide range of organic solvents of different polarities, electron- and proton-donating abilities. Effect of organic solvents on the properties of the BODIPY 1 spectral characteristics was analyzed in details. It was shown that the fluorescence of BODIPY 1 is characterized by a high sensitivity to the nature of the solvent. It was found that the complex, which emits in the blue-green region (433–486 nm), has a high quantum yield of fluorescence (~100%) in non-polar media (cyclohexane, benzene, toluene), while in proton- and especially electron donor media, sharp fluorescence quenching (2.2–31.2 times) of the dye is observed. For a better understanding of the spectral analysis results, a quantum-chemical analysis of the molecular structure, electronic structure, and spectral characteristics of BODIPY 1 was carried out. For the first time, it was shown that BODIPY 1 fluorescence quenching in proton and electron donor media is caused by the formation of a supramolecular dye complex due to specific interactions of solvent molecules with atoms of the meso -propargylamine group. Due to practically useful spectral properties, including the sensitivity of the fluorescence to the nature of the media, BODIPY 1 is recommended as a new effective fluorescent sensor of specific electron and proton donor molecules. • Meso -propargylamino-BODIPY 1 demonstrates the high sensitivity to the nature of the media. • The dye fluorescence quenching increases with increasing the solvent proton and electron donor ability. • Supramolecular complexation leads to the BODIPY 1 fluorescence quenching in polar medium. • BODIPY 1 is recommended as a new fluorescent sensor of specific electron and proton donor molecules.