From diarylruthenium complexes to ortho-metallated ketones: a mechanistic and crystal structure study

Abstract

In the presence of CHCl₃, CCl₄, or Etl, diary1 complexes [Ru(CO)₂(C₆H₄Y-4)(C₆H₄Y′-4)L₂](Y = Y′= Me, L = PMe₂Ph or AsMe₂Ph; Y = Y′= Cl, L = PMe₂Ph; Y = Me, Y′= Cl, L = PMe₂Ph) are converted in solution into products [R[graphic omitted])C₆H₄Y}XL₂], where X = Cl or I. The structure of [R[graphic omitted])C₆H₄Me}Cl(PMe₂Ph)₂], complex (3a), has been determined by X-ray crystallography. The proposed mechanism involves a two-step combination of aryl and carbonyl ligands to give [Ru(CO){OC(C₆H₄Y-4)(C₆H₄Y′–4)}L₂], followed by insertion of the metal into a C–H bond in one of the arene rings and reaction of the resulting hydrido-complex with the halogen-containing compound. Probably as a result of the stereochemistry of the insertion step, the product [R[graphic omitted])C₆H₄Y}XL₂] is initially obtained as an isomer with mutually cis L ligands; this then rearranges to the isolated product with trans L ligands. The iodide ligand in the complex [R[graphic omitted])C₆H₄Me}I(PMe₂Ph)₂] can be displaced by Me₃CNC, and the complete organic ligand in complex (3a) is transferred from ruthenium to mercury on treatment with HgCl₂.