ROTATIONAL ISOMERISM AND VIBRATIONAL SPECTRUM OF 3-BUTENENITRILE

The infrared spectrum of 3-butenenitrile, CH2CH-CH2CN in the liquid, gaseous and solid states has been recorded from 4000 to 100 cm-1. The Raman spectrum of the liquid has also been recorded and depolarization values measured. Both gauche and cis isomers are present at ambient temperature and the cis isomer is the stable form in the solid phase. A complete vibrational assignment based on band contours, positions and depolarization values is given for the cis isomer and the spectra are interpreted in detail. Several of the normal vibrations of the gauche isomer have also been elucidated. From the temperature dependence of two of the low frequency bands, the energy difference between the two isomers was found to be approximately 500 cal. © 1969.