Perhalophenyl–Phosphide: A Couple Needed to Stabilize Phosphide–Gold Complexes

Abstract

The synthesis of gold(III) and gold(I)–gold(III) complexes with phosphide bridges is still a matter that requires solutions for their marked instability, in spite of the affinity of this metal in both oxidation states for phosphorous donor ligands. In the course of our studies, we realized that the presence of perhalophenyl groups of the type pentafluorophenyl or 3,5-dichlorotrifluorophenyl in the complexes gives rise to an increase in their stability that eases their isolation and structural characterization. In this paper, we describe two new fully characterized neutral compounds of this type to extend the knowledge on this family of compounds, [{Au(C6Cl2F3)2}2(µ-PPh2)2] (1) and [{Au(C6Cl2F3)2(µ-PPh2)2Au}2] (2). In this work, we analyze the role of the perhalophenyl groups in the stability of these complexes by using quantum chemical topology methodologies, specifically employing an analysis of the non-covalent interactions (NCIs) in real space and evaluating the electrostatic potential surfaces (ESP). Our findings reveal the existence of appreciable π-stacking interactions among the perhalophenyl and phenyl groups in both compounds, significantly contributing to the stability of the systems.