Electron-Diffraction Study of the Structure and Internal Rotation of Isopropyl Carboxaldehyde

An electron-diffraction study of gaseous isopropyl carboxaldehyde has been carried out for comparison with a parallel study of cyclopropyl carboxaldehyde described in the preceding paper. The isopropyl compound, unlike its cyclic analog, exists in normal trans and gauche rotational isomers. Gauche conformations predominate, accounting for about 90% of the molecules present. Normal values of bond distances and amplitudes of vibration were found and are reported along with other derived molecular parameters. The barrier to rotation was studied and its threefold component was estimated to be in excess of 2 kcal/mole.