ROTATIONAL-ISOMERISM IN 3-METHYL, 3-BUTENENITRILE (METHALYL CYANIDE)

Infrared spectra were obtained for the title compound, CH2C (CH3) CH2 CN, in the liquid and solid states. The rotational isomerism of the molecule was investigated on the basis of solvents and temperature dependence of the absorption spectra. The results revealed the coexistence of three conformational isomers in the liquid state. The energy difference between two of them, the more and the less polar forms as inferred from the solvents variation study, was estimated to be 1.35 kcal/mol (mean value). A normal coordinate analysis assuming valence force field constants and structural parameters was carried out and the calculated frequencies were used as a guide in approximately assigning the observed fundamentals to their normal modes. © 1979.