Inorganic Chemistry, Vol.33, No.19, 4360-4365, 1994
Synthesis and Characterization of Vanadium(V) Mono(Phosphoraniminato), bis(Phosphoraniminato), Tris(Phosphoraniminato), and Tetrakis(Phosphoraniminato) Complexes
V(NSiMe(3))Cl-4 reacts with organophosphorane dichlorides (PCl(2)Ph(3), PCl(2)MePh(2), PCl(2)Me(2)Ph, PCl(2)Me(3)) in dichloromethane to form vanadium(V) phosphoraniminato complexes, V(NPR(3))Cl-4, in excellent yield. Subsequent addition of 1 or 2 equiv of Me(3)SiNPPh(3) to the (triphenylphosphoraniminato)vanadium compound, V(NPPh(3))Cl-4, produces the bis- and tris(phosphoraniminato)vanadium(v) complexes, V(NPPh(3))(2)Cl-3 and V(NPPh(3))(3)Cl-2, respectively. Further addition of Me(3)SiNPPh(3) to the tris(phosphoraniminato)vanadium(v) complex produces only a small equilibrium concentration of the tetrakis(phosphoraniminato) species; however, this compound is isolated in good yield from an unusual reaction between V(NPPh(3))(n)Cl-5-n (n = 1-3) and NH3. An acetonitrile solvate of [V(NPPh(3))(4)]Cl has been structurally characterized and is found to consist of [V(NPPh(3))(4)](+) cations and chloride anions. P-31 and V-51 NMR spectra of this compound show a well-resolved vanadium-phosphorus coupling and support the existence of an analogous four-coordinate structure in solution.
Keywords:BOUND NITROGEN-ATOMS;TUNGSTEN PHOSPHORANIMINATO COMPLEXES;CRYSTAL-STRUCTURE;PHOSPHORANEIMINATO COMPLEX;NIOBIUM;DICATION;LIGANDS