Reactions of acetylenes with noble-metal carbonyl halides II. Insertions into the chloro-platinum bond

The reaction of dichlorodicarbonylplatinum with ROOCCCCOOR (R = CH3, C2H5) in benzene and toluene gives carbonylchloro(1,2-trans-dicarboalkoxy-2-chloroethenyl)platinum compounds by insertion of the active acetylene molecule into the PtCl bond. These chelated stable square-planar vinyl derivatives react with neutral donor ligands to give simple σ-alkenyl derivatives: [Pt(CO)Cl(ROOCCC(Cl)COOR)L] (L = C5H5N, CH3C5H4N), [PtCl(ROOCCC(Cl)COOR)L2] (L = PPh3, PCH3Ph2), and [PtCl(ROOCCC(Cl)COOR)(LL)] (LL = DPE, bipy, Me2bipy). The anionic species [cis-Pt(CO)X2(ROOCCC(Cl)COOR)]- have been isolated as PPN salts by treating the vinyl complexes with Cl-, I- or SCN-. The stereochemistry has been elucidated from spectroscopic data (IR and 1H NMR).