Non-linearity of weak B center dot center dot center dot H-C hydrogen bonds: an investigation of a complex of vinyl fluoride and ethyne by rotational spectroscopy

摘要

Rotational and centrifugal distortion constants were determined for seven isotopomers of a weakly bound complex of vinyl fluoride and ethyne. The complex is planar or nearly planar, with a H of HCCH forming a hydrogen bond to the F atom of vinyl fluoride. The r(0) geometry is: r(F... H) = 2.441(4) Angstrom, phi = 122.7(4)degrees and theta = 36.5(2)degrees, where phi is the angle made by the F...H intemuclear line with the C-F internuclear axis and theta is the angular deviation of the F...H-C nuclei from collinearity. The non-linearity theta is attributed to the effect of a secondary interaction involving the pi-bond of ethyne with one of the H atoms on C-2 of vinyl fluoride. The angular geometry Of C2H3F...HCCH is compared with those of other species C2H3F...HX. (C) 2003 Elsevier Science B.V. All rights reserved. [References: 35]