Platinum–lead bonded complexes

Abstract

The new platinum–lead bonded complexes trans-[PtL₂(PbPh₃)₂](I)(L = PEt₃,AsEt₃) prepared by the reaction of cis- or trans-[PtL₂Cl₂] with LiPbPh₂ are described. Such complexes undergo platinum–lead bond cleavage with various reactants. Thus, potassium cyanide in ethanol gives K₂[Pt(CN)₄] and (C₅H₆)₆Pb₂. Bromine in CCl₄ affords trans-[Pt(PEt₃)₂Br₂] and (C₆H₅)₂PbBr₂. Hydrogen chloride in benzene leads to trans-[Pt(PEt₃)₂Cl₂] and PbCl₂. Homogeneous hydrogenolysis gives an oil tentatively formulated as trans-[Pt(PEt₃)₂(PbPh₃)H].

The complexes undergo neutral ligand exchange with Ph₂P·CH₂·CH₂PPh₂(diphos) to give cis-[Pt(diphos)(PbPh₃)₂]. The above metal–metal bond cleavage reactions are interpreted in terms of primary addition to platinum leading to six-co-ordinated intermediates.

I.r. spectra of the new products are reported. The strength and stability of heterogeneous metal–metal bond in (I) are discussed in relation to similar systems.