Solute-solvent exciplexes as the source of anomalous fluorescence from 4-N,N-dimethylamino-ethylbenzoate in 1,4-dioxane and in polar solvents

Abstract The behaviour of 4-N,N-dimethylamino-ethylbenzoate in its lowest electronically excited singlet and triplet states in solutions in apolar and polar solvents has been investigated by measuring the lifetime and quantum yield of the fluorescence, quantum yield of the triplet state and transient dielectric loss induced by laser pulse excitation. The major conclusion is that the anomalous fluorescence of the compound in 1,4-dioxane and in polar solvents is emitted by solute-solvent exciplexes. The previously reported anomalous fluorescence of the compound in alkanes has not been observed.