15min:

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

The rotational spectra of six isotopomers of the 1,1,2--trifluoroethylene-acetylene complex have been collected in the 6--21 GHz region. In addition to the most abundant isotopomer, spectra are obtained for four isotopomers containing substitution in the HCCH subunit (HCCD, H¹³C¹³CH, and H¹³CCH, which forms two different isotopomers for the complex) and for one isotopomer containing a substitution in the CHFCF₂ subunit (CHF¹³CF₂). The spectra of the three isotopomers with a single substitution of ¹³C are observed in natural abundance upon pulsed jet expansion of a mixture of HCCH, CHFCF₂, and Ar. Both a- and b-type transitions are seen, and the deuterium nuclear quadrupole hyperfine structure in HCCD-CHFCF₂ is resolved and analyzed. Both the Kraitchman substitution coordinates and the spectroscopic constants are consistent with a planar structure in which a hydrogen bond is formed between H in HCCH 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 acetylenic bond.