The mechanisms of the reactions between hydrido-complexes and diazonium salts. Part 1. The reactions of trans-[PtH(Cl)(PEt3)2]

Abstract

The mechanism of the reaction between trans-[PtH (Cl)(PEt₃)₂] and (p-R′C₆H₄N₂)BF₄(R′= NO₂, Cl, F, H, Me, or MeO) has been studied in acetonitrile. It has been shown to involve attack of the diazonium cation on the solvento-species trans-[PtH(NCMe)(PEt₃)₂]⁺, which labilises the hydridogroup resulting in its loss as a proton. Subsequent substitution of the solvento-ligand, in the intermediate [Pt(NCMe)(N₂C₆H₄R′-p)(PEt₃)₂]⁺, by chloride renders the aryldiazenido-ligand sufficiently basic to be protonated yielding the aryldiazene product, trans-[Pt(NHNC₆H₄R′-p)Cl(PEt₃)₂]⁺. The relevance of these studies to the formal ‘insertion’ of unsaturated molecules into the Pt–H bond is discussed.