SCALED ABINITIO FORCE-FIELD AND VIBRATIONAL-SPECTRA OF AZETIDINE

The vibrational spectra are reported for azetidine both in solution and in the vapor phase. A harmonic force field is derived by scaling the ab initio force constants calculated at the 6-31G* level, with the previously reported optimized geometry as the reference structure. The 6-31G* force field for oxetane is also evaluated and scaled to reproduce the literature assignments, so as to provide appropriate factors for the initial scaling of azetidine force field. The calculated frequencies for azetidine, together with the absorption intensities calculated with the 6-31G* atomic polar tensors, are sufficiently accurate that all major features in the experimental spectra are readily assigned. This confirms that only a single conformer, with the NH assuming the equatorial position, is present under the experimental conditions. © 1990 American Chemical Society.