IR SPECTROSCOPIC INVESTIGATION OF SOLVENT EFFECTS AND H-BOND FORMATION ON THE CD STRETCHING FREQUENCY OF CHLOROFORM

Abstract The IR spectra in the region of the CD stretching frequency of deuterated chloroform have been investigated quantitatively with respect to frequency shift &+;ν CD and band area A in several solvents. In particular, dispersion forces influence Δν CD considerably. The band area correlates with the square of the dipole moment of solvents which cannot be considered as H-bond acceptors. After correction for the dipole influence a linear correlation between A and Δν CD is obtained for H-bond acceptor solvents. A comparison of the frequency shifts of the XH bands of chloroform (C–D) and methanol (OH) indicates that, in addition to dispersion, dipole and H-bond interactions, induced dipole moments seem to be of importance for alcoholic solutions. In addition to the possibility of separating contributions of different intermolecular interactions experimentally, the results may help to estimate solvent effects more easily and to develop simple models for the description of the influence of the intermolecular interactions present in different systems.