Raman and DFT study of non-covalent interactions in liquid benzophenone and its solutions

Analysis of intermolecular interactions in liquid benzophenone and its solutions in acetone and acetic acid by Raman spectroscopy and quantum-chemical simulation is presented. The results of the experiment show that in binary solutions of benzophenone, a red shift was observed for the C ˭ O stretching band, and a blue shift was observed for the C–H stretching and breathing bands. Such shifts were predicted to occur due to weak (non-classical) hydrogen bonds of C–H⋅⋅⋅O ˭ C type between benzophenone and solvent molecules. The nature and strength of solute-solvent interactions are discussed. The electron density distribution in benzophenone and its complexes with acetone and acetic acid molecules was visualized using the molecular electrostatic potential surface. The electronic properties of the molecular complexes were characterized using the frontier molecular orbitals and localization functions.