Competition between π-hole interaction and hydrogen bond in the complexes of F2XO (X = C and Si) and HCN.

Complexes F2XO∙∙∙HCN (X = C and Si) have been studied by quantum chemical calculations at the MP2/aug-cc-pVTZ level to investigate the competition between π-hole interaction and hydrogen bond. F2XO has a dual role of a Lewis acid and base with the π-hole on the X atom and the O atom to participate in the π-hole interaction and hydrogen bond with HCN, respectively. Both types of interactions become stronger for X = Si, and the π-hole interaction is much stronger than the hydrogen bond, particularly, the π-hole interaction in F2SiO∙∙∙NCH complex shows a binding energy of -119.8 kJ mol(-1). The C-H∙∙∙O hydrogen bond is dominated by the electrostatic interaction, and this conclusion holds for the π-hole interaction in F2CO∙∙∙NCH complex, but the electrostatic and polarization contributions are similar in F2SiO∙∙∙NCH complex.