Estimation of ground- and excited-state dipole moments of 3-acetoacetyl-coumarin derivatives from a solvatochromic shift method based on the solvent polarity parameter

Abstract The optical properties of 1 (3-acetoacetylcoumarin), 2 (3-acetoacetylbenzo[ f ]coumarin) and 3 (3-acetoacetylbenzo[ h ]coumarin) were investigated by UV/vis absorption and fluorescence spectroscopy in solvents of different polarities at room temperature (298 K). Solvatochromic correlations were used to estimate the ground-state ( μ g ) and excited-state ( μ e ) dipole moments. The excited-state dipole moments for the three molecules were found to be larger than the corresponding ground-state dipole moments.