Theoretical Study of Intermolecular Interactions in Aggregated Ion Pairs [MiM+][C(CN)3-] Ionic

Intermolecular interactions between two cation and two anion in methylimidazolium tricyanomethanide ionic liquid [mim][C(CN)3] have been studied at different levels of theory. Four aggregated ion pairs (A-D) were characterized on the potential energy surface of interaction of two cations with two anions. Structures, interaction energies, hydrogen bonding, physical and topological properties of the ionic complexes have been investigated. Th e effect of different solvents on the stability of complexes and monomers was examined. Th e obtained natural bond orbital parameters show that in all ion pairs the charge transfer takes place from anions to cations. Th e LP(N)→σ*(N–H) and LP(N)→σ*(C–H) donor–acceptor interactions are the most important interactions in these complexes. It is predicted that N∙∙∙H–N interaction is stronger than N∙∙∙H–C one.