Infrared spectra of the hydrogen-bonded pi complex C2H4–HF in solid argon

Abstract

The hydrogen-bonded pi complex C 2 H.--HF has been prepared by codeposition of C 2 H. and HF with excess argon at 12 K. Isotopic substitution in both submolecules identified the complex and provided assignments to v, at 3731 cm -I, VI at 424 and 396 cm -', and v, at 973 cm -1. The observation of a substantial perturbation on the out-of-plane bending mode of the C 2 H. submolecule in the complex without a perturbation on the in-plane bending mode indicates that H-F is bonded to the pi electron system perpendicular to the plane of the molecule. The positions of V, and VI indicate a hydrogen bond of intermediate strength and the splitting in VI is characteristic of the anisotropy in the' hydrogen bonding interaction with a 7r system.

Matrix isolation studies of reactive intermediate complexes

“…However, comparison of fractional shifts, as well as degree of perturbation to base vibrational modes, can shed some light on these interactions. As noted above, Andrews [92][93][94][95] has examined complexes of HF with a range of alkenes and alkynes; Table V compares these results to the C1F complexes reported here. Andrews observed the same general trends reported for the CIF complexes relative to the bond order, and the number of methyl substituents.…”

“…Often, complexes have been postulated in which the Lewis acid interacts with the electron density of the carbon-carbon multiple bond. While hydrogen bonded complexes of alkenes and alkynes have been well studied [92][93][94][95][96][97][98], less was known about the interaction of simple Lewis acids with these species. C1F would be an excellent choice for such studies, because of its simplicity and lack of steric requirements, its ability to form complexes, and the well-characterized diagnostic for complex formation and strength, namely the C1-F stretching frequency.…”

Crystal chemistry of tetraradial species. Part 4. Hydrogen bonding to aromatic π systems: crystal structures of fifteen tetraphenylborates with organic ammonium cations

“…The means of the 26 N....rr, and H(N) ....rr, distances in the normal-bonds sample are 3.25(18) and 2.34 (19) A, respecrelation between these two angles must not be left uninvestigated, it is not certain that 4 is the quantity best suited to serve as a principal parameter in formulating general norms of tively. The corresponding means for particular subsets of the ''Where the nitrogen canies three H atoms, as in 13-15, the positions of these hydrogens are known with less certainty, but they are still adequate for describing the geometry of the bonds (see below).…”

“…Points for the remaining unsolvated TBs all fall below the regression line, most of them considerably below the -3u limit. The cations in these TBs contain either a double bond (19)(20)(21)28), a ring ( l l ) , or a cage (3, 4, 32; also tropanium TB)," i.e. they are all deficient in hydrogen relative to the n-alkyl compounds with the same n value.…”

Hydrogen-bonded complexes of acetylene and acetonitrile: A matrix isolation infrared and computational study

“…Studies of hydrogen-bonded complexes, both experimental and theoretical, are of considerable interest [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The conventional hydrogen bond (H-Bond) where an XAH bond interacts with Y is represented by XAHÁ Á ÁY.…”