Carboxylation of pincer PCP platinum methoxide complexes under formation of metalla carbonates

The ligand 2,6-bis[(diphenylphosphino)methyl]benzene ((PCP)H) was prepared and characterised in an improved manner. With platinum it forms the complex (PCP)PtOTf which reacts with sodium methoxide to give (PCP)PtOMe as the major product together with a small amount of [(PCP)Pt]2-μ-H. The platinum methoxide reacts with carbon dioxide to give (PCP)PtO(CO)OMe. Also the dinuclear [(PCP)Pt]2(μ-O(CO)OMe) is formed in this reaction if (PCP)PtOTf is present. The crystal structures for [(PCP)PtOH2]OTf, PCP)PtOMe, [(PCP)Pt]2-μ-H and [(PCP)Pt]2(μ-O(CO)OMe) are reported.

The compound (PCP)PtOMe was synthesised from the corresponding triflate. It reacts with CO2 to form a metalla carbonate.Figure optionsDownload as PowerPoint slideHighlights
► The phenyl PCP platinum framework allows for the synthesis of a methoxide complex.
► The synthesis is accompanied by some formation of a di-nuclear hydride, presumably formed through β-elimination.
► The methoxide readily inserts carbon dioxide to form a stable metalla carbonate.