An infrared and Raman spectroscopic study of rotational isomerism in 2,3-dicyano-2,3-dimethylbutane

Abstract

The i.r. and Raman spectra of solid 2,3-dicyano-2,3-dimethylbutane consist of relatively few frequencies; this simplicity, together with the presence of additional bands in solution, suggests the existence of only the trans-rotamer in the solid phase and a mixture of the trans- and gauche-rotamers in solution. Raman spectra strongly support this conclusion. A discussion is given of the assignment of the stronger bands to fundamental vibrational frequencies. The relatively weak intensities of the bands due to the gauche-rotamer indicate that in solution the proportion of the gauche-form is considerably smaller than that of the trans-rotamer.