Effect of cooperativity in lithium bonding on the strength of hydrogen bonding: (LiCN) n ···HX (n = 1–5, X = F, Cl) complexes as a working model

Abstract

Quantum chemical calculations are performed to analyze effect of cooperativity in lithium bonding on the strength of hydrogen bonding. Molecular geometries and interaction energies of the complexes are investigated using the MP2 method employing 6-311 ++G** basis set. Our results reveal that strength of hydrogen bonding is enhanced due to cooperativity between lithium bonded complexes. Cooperative effects are found when lithium and hydrogen bonds coexist in the title complexes. These effects are studied in terms of structural, energetic, and dipole moment properties of the complexes. The Bader’s theory of atoms in molecules is applied to characterize the interactions and to analyze their enhancement upon the variation of charge density at critical points. A linear correlation was found between the cooperative effect parameter and magnitude of the product of most positive and negative electrostatic potentials (V S, max V S, min).