Photophysical properties of a new 8-phenyl analogue of the laser dye PM567 in different solvents: internal conversion mechanisms

The photophysical properties of a novel 8-(p-acetoxymethyl)phenyl analogue of the well-known dipyrromethene PM567 laser dye, PAr1Ac, have been studied in liquid solutions by means of absorption and fluorescence techniques. The fluorescence quantum yield and lifetime of PAr1Ac are slightly lower than those of PM567 owing to an increase in the rate of non-radiative deactivation, for which several mechanisms are discussed. The solvatochromic shift of the spectral bands is studied in multitude of apolar, polar and protic solvents by means of a multilinear regression method in which several solvent parameters are simultaneously analysed.