F-H...F-C hydrogen bonds - The influence of hybridization of carbon atom connected with F-acceptor on their properties

Complexes of hydrogen fluoride as the proton donating molecule and fluoro derivatives of methane, ethene and ethyne as the proton acceptors were taken into account to analyze F-H...F-C hydrogen bonds. DFT and ab initio calculations up to the MP2/aug-cc-pVTZ//MP2/aug-cc-pVDZ level of approximation were performed showing the influence of hybridization of C-atom connected with the fluorine acceptor centre on the strength of F-H...F-C hydrogen bond. The AIM ('atoms in molecules') theory was also applied to find and characterize bond critical points. The results of calculations show that F-H...F-C interactions are rather weak hydrogen bonds, except of F-H...F-CH3 complex where the binding energy is greater than that one of the trans-linear water dimer