Transition metal–carbon bonds. Part XXXI. Internal metallations of palladium(II)–t-butyldi-o-tolylphosphine and –di-t-butyl-o-tolylphosphine complexes

Abstract

The complexes trans-[PdCl₂L₂]{L = PBu^t(o-tolyl)₂ or PBu^t₂(o-tolyl)} are shown to undergo internal metallation at the tolyl-methyl group very readily, to give complexes of the type [Pd₂Cl₂(P–C)₂]{(P′–C)= CH₂C₆H₄PBu^t(o-tolyl) and (P″–C)= CH₂C₆H₄PBu₂^t}. The ligand PBu^t₂(o-tolyl) undergoes metallation more readily (in deuteriochloroform at ca. 35°) than PBu^t(o-tolyl)₂. The chloride bridges of the binuclear complexes [Pd₂Cl₂(P–C)₂] are replaced on treatment with silver carboxylates to give the compounds [Pd₂X₂(P–C)₂](X = OAc or OBz). These chloride bridges are split by various ligands (e.g. PPh₃, acetylacetonate, (–)-stilbenediamine etc.) to give mononuclear species.