Conformational studies of 2‐methylbutyronitrile and 3‐methyl‐1‐pentyne by vibrational spectroscopy and molecular mechanics

Vibrational spectra were obtained for the structurally similar compounds 2‐methylbutyronitrile and 3‐methyl‐1‐pentyne, and vibrational assignments were made with the aid of normal coordinate calculations. Molecular mechanics calculations were also made, and each compound was shown to exist as a mixture of three conformers, with the most stable conformer being the one with the two methyl groups trans to each other. Results of the calculations are given.