New tetra- and pentacoordinate nickel(I) complexes

The reduction of nickel(II) halides with NaBH4 in ethanol has been studied in the presence of various tertiary phosphines and arsines. Complexes of the type XNiL3 have been isolated in this way when X = Cl, Br, I and L = PPh3, AsPh3, no reaction being observed when L = PEt3, PBu3 and Ph2P(CH2)2PPh2. The reaction of XNiL3 with CO gas at room temperature produces pentacoordinate carbonyl complexes XNi(CO)2L2 when L is triphenylphosphine. The lack of stability prevents the isolation of similar complexes when L is trip henylarsine. Structural data obtained by i.r. spectroscopy and susceptibility measurements as well as chemical behaviour of the new complexes are described.Comisión Asesora de Investigación Científica y Técnic