Intermolecular forces and solvent effects, II. Band intensities

Abstract

The intensities and shapes of vibration bands of the H —C and D — C groups in HCN, DCN and propargyl chloride, and of the C≡N group in these and other nitriles have been measured in a number of solvents. The results have been discussed in relation to Buckingham’s theory of solvent effects. The relative significance of bulk dielectric effect and intermolecular interaction varies in different cases. A marked contrast in the effect of solvent has been found between CH 3 CN and CCl 3 CN used as solutes, which suggests that in the formation of solvent complexes the dipole derivative of the C ≡ N group may change sign. Further data have been obtained about the band shapes which suggest that the Lorentz function is rarely satisfactory, and in different solvents a given vibration band may have very different contour.