A characterisation of the complex vinyl fluoride⋯hydrogen fluoride by rotational spectroscopy and ab initio calculations

Combined use of rotational spectroscopy and ab initio calculations at the MP2/6-311++G(d,p) level of theory shows that the complex formed between vinyl fluoride and hydrogen fluoride has a planar geometry in which HF forms a hydrogen bond to the F atom of vinyl fluoride. With ϕ = the angle CF⋯H = 121.4° assumed from the ab initio calculation, the distance r(FH) = 1.892(14) Å and the angular deviation θ = 18.7(15)° of the F⋯H–F nuclei from collinearity were obtained by fitting the principal moments of inertia of the two isotopomers C2H3F⋯HF and C2H3F⋯DF investigated.