Theoretical study of the the interaction between C,H6 , CH,CH2F, CH,CHF2 , CH2FCHF2 and CHF2CHF2 with H20.

Abstract

The binding energies of some the complexes (corrected by ZPE and BSSE) range between 0.49 kcal.mol^-1 and 2.62 kcal.mol^-1, There is a contraction of the CH

bond bound to oxygen atom, a blue shift. There is a decrease of the occupation of the s*(ClH2) and s*(C1H3) antibonding orbitals in the IIA, IIIB, IV respective complexes performed in the firgure 1. The NB0 analysis indicates that the H-index is not a reason for physical nature of improper blue-shifting hydrogenbond in the complexes examined, but the EDT and the increase of s-character of CH bonding are major reasons for the contraction. The data obtained in this work allow us to establish the following correlations between the frequency shifts of the stretching vibrations and variations of the corresponding bond lengths: Dv(C-H) = -12956 Dv(C-H) +2.086 (1), Dv(O-H) = -13349 Dv(O-H)  + 10.725. We also have deduced the correlation: Dv(O-H) = 2.5075 Ds*(O-H) -0.0026