Synthesis and structure of dinuclear diphosphine-bridged palladium(II) complexes

The dinuclear dicationic complexes [(Pd(dppe)(R))(2)(mu-diphos)]X-2 (diphos = dppe; R = Ph (1), R = Me (2), diphos = dppp, R = Ph (3)) were prepared b y the addition of a bidentate diphosphine to [Pd(dppe)(R)(PMes(2)H)](+) by treatment of [Pd(dppe)(R)(X)] (X = Cl, I) with Ag+ and a bidentate diphosph ine, or by reaction. of [Pd(dppe)(Ph)(X)] (X = Pr, I) and dppe. NMR and cry stal structure data show that the structure of 1 is the same in solution an d in the solid state and allow structural and spectroscopic comparison of c helate and bridging dppe ligands at the same metal center.