Tuning of pnicogen and chalcogen bonds by an aerogen-bonding interaction: a comparative ab initio study

Using high-level ab initio calculations, the cooperativity effects between an aerogen-bonding and a pnicogen- or chalcogen-bonding interactions are studied in ternary Y center dot center dot center dot PH2CN center dot center dot center dot ZO(3) and Y center dot center dot center dot SHCN center dot center dot center dot ZO(3) complexes (Y = NH3, N-2 and Z = Ar, Kr, Xe). A detailed analysis of the structures, interaction energies and bonding properties is performed on these systems. For each set of the complexes, a favourable cooperativity is observed between Z center dot center dot center dot N and P/S center dot center dot center dot N interactions, especially in complexes involving NH3 and XeO3 molecules. It is found that for a given Y or Z, the amount of cooperativity effects in Y center dot center dot center dot PH2CN center dot center dot center dot ZO(3) complexes are important than Y center dot center dot center dot SHCN center dot center dot center dot ZO(3) ones. For each ternary complex considered, the effect of a Z center dot center dot center dot N aerogen bond on a P/S center dot center dot center dot N bond is more pronounced than that of a P/S center dot center dot center dot N bond on a Z center dot center dot center dot N bond. The mechanism of the cooperativity effects in the ternary complexes is studied by electron density difference, quantum theory of atoms in molecules and natural bond orbital analyses. The solvent effects are also studied on the interaction energy and cooperativity of Z center dot center dot center dot N and P/S center dot center dot center dot N bonds in the ternary systems. [GRAPHICS] .