Synthesis, characterization and reactivity of binuclear palladium(I)bis(diphenylphosphino)amine complexes

The binuclear Pd(I) complex [Pd-2(mu-dppa)(2)(CH3CN)(2)][BF4](2) (1), where dppa is the bridging diphosphine ligand bis(diphenylphosphino)amine, was prepared by the reaction of [Pd(dppa)(2)][BF4](2) and 1/2 equiv. of [Pd-2(dba)(3)]. The acetronitrile ligands in complex 1 are readily displaced by other ligands. Substitution of one or both of the acetronitrile ligands of the dimer 1 with Cl-, Br-, I-, (CN)(-) and PPh(3) is described. P-31 NMR and mass spectral data for the complexes are reported. The single crystal X-ray structures of the binuclear complexes, [Pd-2(mu-dppa)(2)(PPh(3))(THF)][BF4]. 4THF, [Pd-2(mu-dppa)(2)Cl-2]. 3CH(3)CN have been determined. Attempts to react the binuclear complex [Pd-2(mu-dppa)(2)I-2] with ligands capable of bridging the Pd-Pd bond (CO, SO2 and HgCl2) were successful.