Activation of white phosphorus in the coordination sphere of nickel complexes with σ-donor ligands

Routes of white phosphorus activation in the coordination sphere of the nickel complexes with different ligands are shown. The first route is based on the coordination of a P-4 Molecule with the metal, resulting in the deformation of the P4 tetrahedron without destruction. This case is characteristic of the NiX2L complexes, which are reduced at higher cathodic potentials (/E-red/ > 0.9 V) (X = BF4, Br, and Cl; L is bpy in DMF, MeCN, and acetone; 2,9-dimethyl-1,10-phenanthroline (phen) and PPh3 in DMF and acetone). To cleave the P-P bonds in the P4 molecule, this complex should be reduced on the electrode. The second route is the oxidation of white phosphorus in the coordination sphere of the Ni-II complex. It occurs when the complex has a sufficiently high oxidizing ability and is reduced rather easily (/E-red/ < 0-9 V) (X = BF4, L is 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) in acetone; 1,1',5,5'-bis[methylenedi(p-phenylene)]di(3,7-diplienyl-1,5-diaza-3,7-diphosphacyclooctane) (n(2)p(2)) in DMF; phen and PPh3 in MeCN). The P-4 molecule opening is observed to form a new Ni-I complex containing the (P-3) fragment, for example, [(triphos)Ni(P-3)Ni(triphos)](BF4)(2).