The microwave spectrum, dipole moment, and structure of cyclopropyl carbinol

The microwave spectra of cyclopropyl carbinol [Formula: see text] and its deuterated (—OD) form were studied in the region of 8 to 35 gHz. Only one of the possible rotational isomers was identified. The measured rotational constants and dipole moments for C 3 H 5 CH 2 OH and C 3 H 5 CH 2 OD are, respectively, A (mHz): 12485.13, 12064.04; B (mHz): 3236.46, 3177.22; C (mHz): 2894.38, 2826.19; κ: −0.928665, −0.924001; μ a (D): 1.81, 1.78; μ b (D): 0.36, 0.32; μ c (D): 0.31, 0.30; μ total (D): 1.87, 1.84.Rotation is apparently hindered by hydrogen bonding between the hydroxyl hydrogen and the electrons in the strained bonds of the cyclopropyl ring.