Cooperativity between the hydrogen bonding andσ-hole interaction in linear NCX···(NCH)n=2–5and O3Z···(NCH)n=2–5complexes (X = Cl, Br; Z = Ar, Kr): a comparative study

Abstract

Quantum chemical calculations are performed to investigate the cooperativity of hydrogen bonding with halogen or aerogen bonding interactions in linear NCX···(NCH)n=2–5and O3Z···(NCH)n=2–5clusters, where X = Cl, Br and Z = Ar, Kr. To understand the cooperativity mechanism in these systems, the corresponding binary NCX···NCH and O3Z···NCH complexes are also considered. The binding distances, interaction energies, and bonding properties of the NCX···(NCH)n=2–5and O3Z···(NCH)n=2–5clusters are analyzed in detail. It is found that the cooperative effects in the hydrogen bonding tend to strengthen X···N and Z···N interactions. For both NCX···(NCH)nand O3Z···(NCH)nclusters, a small bond shrinkage is observed from n = 4 to n = 5, which suggests that the cooperativity effects are almost saturated in the larger clusters (n > 5). As the size of the X or Z atom is increased, the magnitude of the cooperative energy in these systems is also increased, which is mainly ascribed to changes in electrostatic potentials and orbital interactions. Our results indicate that the cooperative effects lead to a substantial change in the14N nuclear quadrupole coupling constants of the NCH molecule.