Complexes of mixed phosphorus–nitrogen ligands. Part II. Some complexes of cobalt(II) and Nickel(II) with Three o-dimethylamino-phenylphosphines

Abstract

The ligands o-Me₂N·C₆H₄PPh₂, (o-Me₂N·C₆H₄)₂PPh, and (o-Me₂N·C₆H₄)₃P (abbreviated, respectively, to PN, PDN, and PTN) form high-spin cobalt(II) complexes of the type [CoX₂(ligand)](X = Cl, Br, and l) which have pseudo-tetrahedral structures, in which one phosphorus and only one of the nitrogen atoms are bonded to the cobalt atom. The following structural assignments have been made for the high-spin nickel complexes of these ligands: (1)[NiX₂(PN)](X = Cl and Br) are pseudo-tetrahedral in dichloromethane solution and are pentaco-ordinate dimeric, with bridging halogen atoms, in the solid state; (2)[Nil₂(PN)] is pseudo-tetrahedral both in the solid state and in dichloromethane solution; (3)[NiX₂(ligand)](X = Cl and Br; ligand = PDN and PTN) are pentaco-ordinate dimeric, with bridging halogen atoms, in the solid state and, in dichloromethane solution, they are likely to occur as mixtures of tetrahedral and pentaco-ordinate species with one phosphorus and two nitrogen atoms bonded to the nickel atom; (4)[Nil₂(ligand)](ligand = PDN and PTN) is pseudo-tetrahedral in dichloromethane solution with one phosphorus and one nitrogen atom co-ordinated to the nickel atom and, in the solid state, there appears to be a mixture of tetrahedral and pentaco-ordinate species.