High resolution rotational spectroscopy and ring-puckering conformation of 3-hydroxytetrahydrothiophene

High resolution rotational spectra have been recorded for 3-hydroxytetrahydrothiophene and its (34)S and (13)C isotopomers using a Fourier-transform microwave spectrometer. The spectroscopic moments of inertia were used to least-squares fit the ring puckering conformation. The structure was found to have C(3) puckered out of plane, and it is stabilized by a 2.634-Angstrom hydrogen bond from the hydroxyl group to the thioether. Ab initio calculations, at the MP2/ 6-31G** level, also found that the C(3) puckered conformation is the lowest energy conformation of the ring. Measurements of the Stark shifts were used to determine the dipole moment (mu = 1.556 (4) D) of 3-hydroxytetrahydrothiophene and its projections onto the principal inertial axes (mu(a) = 0.024 (5) D, mu(b) = 0.944 (5) D, and mu(c) = 1.237 (4) D). (C) 2002 Elsevier Science B.V. All rights reserved.