Photophysical investigations of the solvent polarity effect on the properties of coumarin-6 dye

Photophysical properties of coumarin-6 dye in different solvents reveal its behavioural differences in non-polar and other solvents. Where the photophysical properties of the dye follow more or less linear correlation with Lippert–Mataga solvent polarity function for moderate to higher polarity solvents, they undergo unusual deviations in non-polar solvents. It is inferred that the dye adopts different conformations at its 7-NEt2 group in non-polar and other solvents, which is also supported by results from quantum chemical calculations.