15min:

MARK D. MARSHALL, HELEN O. LEUNG, Department of Chemistry, Amherst College, P.O. Box 5000, Amherst, MA 01002-5000.

The rotational spectra of four isotopomers of the 1,1,2--trifluoroethylene-hydrogen fluoride complex (HF-CHFCF₂, DF-CHFCF₂, HF-¹³CHFCF₂, and HF-CHF¹³CF₂) have been collected in the 7--22 GHz region with a Fourier transform microwave spectrometer. The complexes are generated using pulsed jet expansion of a mixture of HF (or DF), CHFCF₂, and Ar, and the two ¹³C-containing isotopomers are observed in natural abundance. Only a-type transitions are seen for all isotopomers, and for most lines in the DF-containing isotopomer, deuterium nuclear quadrupole hyperfine structure is not resolved within the experimental linewidth of 10--15 kHz. Both the Kraitchman substitution coordinates and the rotational constants are consistent with a planar structure in which a hydrogen bond is formed between H in HF and the F on C-2 in CHFCF₂ with a secondary interaction between the H (geminal to the F involved in the hydrogen bond) in CHFCF₂ and the F in HF.