The X∙∙∙Au interactions in the CF3X (X = Cl, Br) ∙∙∙Aun (n = 2, 3, and 4) complexes

I have performed quantum chemical calculations for the CF3X (X = Cl, Br) ∙∙∙Aun (n = 2, 3, and 4) complexes at M05-2X/aug-cc-pVDZ(PP) level. Two types of optimized structures were obtained. Type I complexes are stabilized by the coordination force between the negative electrostatic potential of halogen atom and the gold atom, and type II complexes contain halogen bonds formed between the σ-hole of the halogen atoms and the negative electrostatic potential of Aun. Results of the interaction energy indicate that type I complexes are more stable than type II complexes. AIM analysis reveals that type II complexes are a closed shell interaction and there is a partially covalent nature for type I complexes.