Ping-Pong at Gold: Proton Jump Between Coordinated Phenyl and η1-Benzene Ligands, A Computational Study

A DFT computational investigation predicts that the Au(III) complex (bpy)Au(C6H5)(2+) reacts with benzene to furnish square planar (bpy)Au(C6H5)(eta(1)-C6H6)(2+). Intramolecular processes that occur within this species have been located, and the energetics of all processes have been quantified. The dynamic processes that have been identified are (1) benzene ring rotation with respect to Au, (2) direct hydrogen transfer from the benzene to the phenyl ligand, (3) hydrogen transfer from the ipso to the ortho positions in the coordinated benzene ligand, and (4) hydrogen transfer from the benzenium ligand formed by the ipso/ortho isomerization to the phenyl ligand. Similarities and differences are seen between the behavior of (bpy)Au(C6H5)(eta(1)-C6H6)(2+) and previously reported isoelectronic Pt(II) complexes. Preliminary experimental results related to this chemistry are reported, and possible consequences for C-H bond activation mediated by gold are discussed.