Thermochromic absorption, fluorescence band shifts and dipole moments of BADAN and ACRYLODAN

Abstract

Using the thermochromic shift method of absorption and fluorescence bands, the electric dipole moments in the ground (μg) and excited (μe) state are simultaneously determined for BADAN (6-bromo-acetyl-2-dimethylamino-naphtalene) and ACRYLODAN (6-acrylolyl-2-dimethylamino-naphtalene) in ethyl acetate. For these compounds the same ratio μe/μg = 2.9 was found, which is similar to that of PRODAN (6-propionyl-2-dimethylamino-naphtalene). The estimated empirical Onsager radii a for BADAN and ACRYLODAN are the same, and they are somewhat smaller than the calculated geometrical values.