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Download fileThe Microwave Spectrum and Molecular Structure of (Z)‑1-Chloro-2-Fluoroethylene–Acetylene: Demonstrating the Importance of the Balance Between Steric and Electrostatic Interactions in Heterodimer Formation
journal contribution
posted on 10.07.2017, 00:00 authored by Helen O. Leung, Mark D. Marshall, Nazir D. KhanThe structure of
the gas-phase heterodimer formed between (Z)-1-chloro-2-fluoroethylene
and acetylene is determined
via Fourier transform microwave spectroscopy from 5.5 to 20.8 GHz.
In the first instance where in the presence of both a fluorine atom
and a chlorine atom on the haloethylene the protic acid binds to the
chlorine atom, the acetylene adopts a configuration similar to that
in the analogous complex with vinyl chloride. Positioned in a manner
to interact favorably with both the chlorine atom and the hydrogen
atom geminal to it, the acetylene molecule is able to maximize the
overall electrostatic stabilization even though other regions of the
haloethylene offer individual sites of greater positive or negative
electrostatic potential. Detailed comparison with the vinyl chloride–acetylene
complex suggests that the presence of the fluorine atom weakens the
hydrogen bond but strengthens the interaction between the geminal
hydrogen atom and the triple bond.