Reactions of the bis(iminophosphoranyl)methane ligand CH2(Ph2P=NSiMe3)2 with nickel(II) halides and the structural characterization of ligand fragmentation products

While anhydrous nickel(II) chloride reacts with CH2(Ph2P=NSiMe3)(2) to afford the pseudotetrahedral complex NiCl2[CH2(Ph2P=NSiMe3)(2)] (2), the analogous reaction with anhydrous nickel(II) iodide gives the structurally related complex NiI2[CH2(PPh2= NSiMe3)(PPh2=NH)] (3) in which one of the trimethylsilyl groups of 1 has been replaced by hydrogen. Another reaction in which the fragmentation of 1 occurs is that with the hydrate NiCl2-6H(2)O; in this case a square-planar nickel(II) complex of composition [Ni{Ph2PCH2PPh2(=NH)}(2)]Cl-1.25(NO3)(0.75) (4) was identified as one of the products. The phosphonium salt [Ph2P(NH2)-NPPh2(CH3)]I (5) is found to be a major product of the reaction between 3 and CO. The structures of 2-5 have been established by X-ray crystallography. (C) 2002 Elsevier Science B.V. All rights reserved.