A theoretical evidence for mutual influence between S•••N(C) and hydrogen/lithium/halogen bonds: competition and interplay between π-hole and σ-hole interactions

Ab initio calculations were performed to investigate the cooperativity between the S center dot center dot center dot N(C) bond and the hydrogen/lithium/halogen bond interactions in O2S center dot center dot center dot NCX center dot center dot center dot NCH and O2S center dot center dot center dot CNX center dot center dot center dot CNH triads (X=H, Li, Cl, and Br). To understand the properties of the systems better, the corresponding dyads are also studied. It is evident that the lithium bond has a bigger influence on the chalcogen bond than vice versa. The results indicate that the enhanced interaction energies of the S center dot center dot center dot N(C) and X center dot center dot center dot N(C) interactions in the triad increase in the order NCCl < NCBr < NCH < NCLi and CNCl < CNBr < CNH < CNLi. This is the order of the increasing positive electrostatic potential V (S,max) on the X atom. The nature of S center dot center dot center dot N(C) and X center dot center dot center dot N(C) interactions of the complexes is unveiled by energy decomposition analysis and natural bond orbital (NBO) theory. The cooperativity between both types of interaction is chiefly caused by the electrostatic effects.