15min:

RANGANATHAN SUBRAMANIAN, Department of Chemistry, Wesleyan University, Middletown, CT 06459; ROBERT K. BOHN, Department of Chemistry, University of Connecticut, Storrs, CT 06269; AND STEWART E. NOVICK, Department of Chemistry, Wesleyan University, Middletown, CT 06459.

Microwave spectroscopic studies of substituted propynes, CH₃-CC-X, have increased our understanding of the nature and origin of the potential barriers for internal rotation. Specifically, the potential barriers have been measured for the groups, -CD₃, -CH₂Cl, -SiH₃, and -COF, bonded to the propynyl fragment, with reported 3-fold barriers of 5.62(16), 10.05(9), 3.77(70) and 2.20(12) cm^-1 respectively. We report here a study of the rotational spectrum of 2-butynol, CH₃-CC-CH₂OH. 2-butynol has two low energy rotational conformers with the OH group either anti or gauche with respect to the propynyl moiety. The study of 2-butynol was performed with a pulsed-jet, Fourier Transform Microwave Spectrometer. The rotational spectrum of one species including tunneling splittings has been assigned and is consistent with the gauche conformer. A preliminary value of the 3-fold barrier is 12.5(4) cm^-1. Unassigned transitions in the spectrum may be due to the other conformer.