Hydrogen bonding involved with superhalogen MX2NY: its influence on the structure and stability of the superhalogen

The hydrogen-bonded complexes formed of superhalogen MX₂NY (M?=?Li, Na; N?=?Be, Mg; X, Y?=?F, Cl, Br) and hydrogen fluoride have been investigated with quantum chemical calculations at the MP2/aug-cc-pVDZ and M06-2X/aug-cc-pVDZ levels of theory. It was shown that the M06-2X method presents similar results with the MP2 method. The strength of hydrogen bonding is related with the nature of metal and halogen atoms. The metal with greater electron-donating ability leads to a stronger hydrogen bond, whereas the halogen with bigger electron-withdrawing ability also results in the stronger hydrogen bond. The presence of hydrogen bond has a small effect on the structures of the superhalogen and contributes to the stability of the superhalogen.