Synthesis, characterization and reactivity of bis(diphenylphosphino) amine nickel complexes

The binuclear Ni(0) complexes [Ni2(μ-CO)(CO)2(μ-L2)2 (3), where L2 is the bridging diphosphine ligand bis(diphenyl-phosphino)amine (1H) or bis(diphenylphosphino)methylamine (1Me), have been prepared by the reaction of [Ni(CO)4] and L2. The bridging CO ligands in complexes 3 are reversibly displaced by SO2 yielding [Ni2(μ-SO2)(CO)2(μ-L2)2] (4). The single crystal X-ray structure of the binuclear complex. [Ni2(μ-SO2)(CO2)(μ-(PPh2)2NH)2] (4H), is presented. [Ni2(μ-SO2)(CO)2(μ-(Ph2P)2−NH)2]·(C8H10) crystallizes in the monoclinic space group C2c, Z=4 with lattice parameters a = 27.227(5), b = 9.543(2), c = 22.979(4) Å and β = 113.26(3)°. Reaction of the complexes 3 with X2, where X = Cl or I, ultimately gives [NiX2L2] (5), although intermediates in the reactions are observed. 13PNMR and mass spectral data for teh complexes are reported. Attempts to react the binuclear complexes 3 with several other ligands were unseccesful.