Far‐infrared spectra and hindered pseudorotation of 1,3‐oxathiolane Academic Article uri icon


  • The far-infrared spectra arising from the two out-of-plane ring vibrations of 1,3-oxathiolane have been recorded and analyzed. Fifteen pseudorotational (ring-bending) transition frequencies were observed in the 25-125 cm-1region and were fit with the one-dimensional potential function V(cm-1) = -541 (1 - cos 2φ) + 139(1 - cos 4φ). The molecule is twisted with a barrier to pseudorotation of 541 ± 20 cm-1(1.54±0.06 kcal/mol). The spectra recorded include transition frequencies occurring above the barrier, and this is the first molecule (other than a nearly free pseudorotor) for which such bands have been seen. Seven radial transitions arising from three different pseudorotational states have also been observed in the 297-317 cm-1region. Those in the pseudorotational ground state can be fit with a one-dimensional double-minimum function with a barrier to planarity of 2720 cm-1. However, this value for the one-dimensional approximation is believed to be too high. Difference bands (180-240 cm-1), sum bands (398-426 cm-1), and double quantum transitions (144-220 cm-1) were also detected and used to confirm the assignments. © 1992 American Institute of Physics.

author list (cited authors)

  • Leibowitz, S. J., Laane, J., Verastegui, R., & Villarreal, J. R.

citation count

  • 8

publication date

  • May 1992