An ab initio study on properties of cationic chalcogen bonds in XF2Y+NCZ (XH, CN, F; YS, Se; ZH, Cl, Br) complexes

The geometries, interaction energies, and bonding properties of cationic chalcogen bonds are studied in binary complexes XF(2)Y(+)NCZ (XH, CN, F; YS, Se; ZH, Cl, Br). The nature of these interactions is studied by a vast number of methods, including molecular electrostatic potential (MEP), Noncovalent Interaction Index (NCI), quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) analyses. The interaction energies of these complexes vary between -20.94kcal/mol in HF2S+NCH and -33.72kcal/mol in F3Se+NCBr. According to the QTAIM analysis, all these cationic chalcogen bonds are classified as a closed-shell interaction with a partial covalent character. Moreover, cooperative effects between cationic chalcogen bond and hydrogen or halogen bond interactions are studied in ternary XF(2)Y(+)NCZNH(3) complexes. These cooperative effects are analyzed in terms of the parameters derived from the QTAIM and NBO analyses, and electron density difference plots. [GRAPHICS]