NICKEL(II) AND NICKEL(0) COMPLEXES CONTAINING 2-PYRIDYLPHOSPHINE LIGANDS, INCLUDING WATER-SOLUBLE SPECIES

The paramagnetic, S = 1, NiX(2)L(2) (X = Cl or Br, L = PPh(3-n)py(n), n = 1-3), and diamagnetic NiBr2[d(py)pe] (4b) complexes have been isolated, generally as solvates, where py = 2-pyridyl and d(py)pe = py(2)P(CH2)(2)Ppy(2). Also isolated are the diamagnetic Ni(CO)(2)(PPh(2)py)(2) (5), Ni(CO)(2)[d(py)pe] (7), Ni(PPh(2)py)(4), Ni(PPhpy(2))(4) and Ni[d(py)pe](2), sometimes as hydrates. The complexes, except for 5 which contains paramagnetic impurities, analyze well, and have been characterized by H-1 and P-31{H-1} NMR (for diamagnetic species), IR (for the carbonyls) or magnetic moment data (for the paramagnetic species). NMR evidence for in situ formation of Ni(CO)(2)(PPhpy(2))(2) and Ni(Ppy(3))(4) is also presented. Of note, NiX(2)L(2), 4b and 7 are water-soluble, possibly because of protonation of the pyridyl-N atoms, although this remains to be established; even non-aqueous solutions of these Ni(II) species are moisture-sensitive, In contrast to Ni(PPh(3))(4), at ambient conditions the NiL(4) species show little tendency to dissociate in benzene or toluene.