Raman spectroscopy: a structural probe of solute-solvent interactions in ethyl 4-(dimethylamino)benzoate

Raman spectra of ethyl 4-(dimethylamino)benzoate (DMABEE) were recorded in 18 solvents of varying polarity and hydrogen bonding strength to elucidate the molecular mechanism of solute-solvent interactions in condensed phase. Frequency shifts were observed in the vibrational frequencies of the CO stretching, the CO stretching and the OCO bending modes, as a function of increasing solvent acceptor number. A molecular model of DMABEE-solvent interaction is proposed based on solute-solvent hydrogen bonding and π-π interactions. These results suggest that vibrational spectroscopy provides a mode-specific measure of solute-solvent interactions.