15min:

RICHARD J. LAVRICH, RACHELE L. RHEA, JAMES W. MCCARGAR AND MICHAEL J. TUBERGEN, Department of Chemistry, Kent State University, Kent, OH 44242.

The ring puckering conformation of 3-hydroxytetrahydrofuran, a five-membered heterocyclic ring, has been determined from rotational spectroscopy. Rotational constants for the normal isotopomer are A~=~5581.8230 (7), B~=~3638.8316 (7), and C~=~2924.7410 (7) MHz; rotational spectra were also recorded for four ¹³C isotopic species in natural abundance. The best fit structure is a C_4' endo conformation with an intramolecular hydrogen bond from the hydroxyl to the ring oxygen. Projections of the dipole moment on the inertial axes, µ_a~=~0.956 (1) D, µ_b~=~0.875 (2) D, and µ_c~=~1.050 (2) D, were determined from Stark effect measurements. The experimental structure is nearly identical to the lowest energy ab initio conformation (MP2/6-31+G**).