SOLVENT-INDUCED EFFECTS ON INFRARED SPECTRA
Abstract
The historical development of theories for solvent-induced IR frequency shifts is given and several of these theories are then examined in the light of accurate experimental data. The bulk dielectric theory of Buckingham predicts that the ratio of the integrated intensity of an absorption band and the square of its frequency is an isotopic invariant. This prediction is checked using the C-H and C-D stretching bands of CHCl3 and CDCl3; CHCl2Br and CDCl2Br; and CHBr3 and CDBr3. Ratios of 1.73, 1.54, and 1.20, respectively, are observed. These values are in significant disagreement with the predicted value of unity. Bellamy-type plots are constructed for the C=O vibrations of a number of solutes and, in general, the resulting curves do not pass through the origin as predicted. Theoretical band contours resulting from two overlapped bands are computed for various band maxima separations, and the effect of intensity changes of the individual bands on the shape of the resultant contour is discussed. These theoretical predictions are then applied to the interpretation of a number of mixed solvent studies which show the complexity of most solvent- solute interactions. Finally, these techniques are applied to the 750 reciprocal cm band of tetralin and the 680 reciprocal cm band of benzene which are unusual bands in that they show a blue-shift with increasing solvent polarity.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 24, 1963
- Accession Number
- AD0407429
Entities
People
- R. E. Kagarise
Organizations
- United States Naval Research Laboratory