Photophysical properties of 2-picolinoylpyrrole boron complex in solutions

Photophysical properties of boron 2-picolinoylpyrrole complex (BOPPY) were investigated by UV–Vis absorption, fluorescence spectra and fluorescence lifetime measurements in various solutions. The absorption peak of BOPPY was shifted to blue with increasing the solvent polarity. The fluorescence peak, on the other hand, was shifted to red with increasing the solvent polarity. The electronic structure of BOPPY was calculated by the molecular orbital method to reveal the charge transfer character. The magnitude of change in the dipole moment was calculated by the Lippert–Mataga equation. The fluorescence lifetime and fluorescence quantum yield were measured in solvents as a function of dielectric constant. These results suggest that the BOPPY has an intramolecular charge transfer (ICT) character in the excited state.