The Pt (II)⋅⋅⋅Cl Interactions: Nature and Strength

Abstract

AbstractThe Pt (II)⋅⋅⋅Cl interactions between trans‐Pt (NH3)2X2/cis‐Pt (NH3)2X2 (X=OH, F, Cl, Br) and ClF were constructed and studied by Møller‐Plesset perturbation theory (MP2) method. The metal Pt (II)‐complex could act as the halogen bond acceptor, the Pt (II)⋅⋅⋅Cl interaction strength depends on the nature and the configuration of platinum (II) ligands: the metal halogen‐bonding interactions in trans‐Pt (OH)2(NH3)2⋅⋅⋅ClF/cis‐Pt (OH)2(NH3)2⋅⋅⋅ClF are obviously stronger than those in trans‐PtX2(NH3)2⋅⋅⋅ClF/cis‐PtX2(NH3)2⋅⋅⋅ClF (X=F, Cl, Br); the halogen bonds in cis‐complexes are somewhat stronger than those in respective trans‐complexes. This particular Pt (II)⋅⋅⋅Cl interactions is much stronger than hydrogen bond and has some degree of covalent character. For the Pt (II)⋅⋅⋅Cl interactions, the charge transfer between the related molecular orbitals of PtX2(NH3)2 and ClF are obvious, which is consistent with that the exchange energy contributes most to the total interaction energy. The stronger of the Pt (II)⋅⋅⋅Cl interactions, the more decreased electron density outside Pt (II) facing the chlorine atom, and the more increased electron density between Pt (II) and Cl, indicating that the polarization effect plays an important role in the formation of the Pt (II)⋅⋅⋅Cl interactions.