[Mo(NPPh3)4]2+ [MoNCl3(NPPh3)]2− · C7H8, ein Phosphaniminato-Komplex mit einem Dikation von Molybdän(VI)

Mo(NPPh₃)₄]²⁺ MoNCl₃(NPPh₃)]₂^? · C₇H₈, a Phosphoraneiminato Complex with a Dication of Molybdenum(VI). The title compound was prepared by the reaction of MoNCl₃ with Me₃SiNPPh₃ in acetonitrile solution. Red single crystals separated upon addition of toluene. They were characterized by IR spectroscopy and by an X-ray structure determination. (Space group P1 , Z = 2, 6918 observed unique reflections, R = 0.059. Lattice dimensions at 20°C: a = 1 181.4, b = 2 021.4, c =2 409.7pm; α = 65.87°, β = 101.09°, γ= 78.97°). In the dication Mo(NPPh₃)₄]²⁺ the molybdenum atom is surrounded in a tetrahedral fashion by the four nitrogen atoms of the phosphorane iminato ligands. The MoN and PN bond lengths correspond well with double bonds. In the two anions MoNCl₃(NPPh₃)]^?, which occur in different conformations, the molybdenum atoms are fivefold coordinated by the terminal nitride ligand Mo?N: in axial positions and by the three chlorine atoms and the nitrogen atom of the (NPPh₃)^? ligand in the equatorial positions.