80594-71-4Relevant articles and documents
Stabilization of RN=NN=PR3. Preparation and structural characterization of stable tetraarylphosphazide complexes containing molybdenum and tungsten
Hillhouse, Gregory L.,Goeden, Gary V.,Haymore, Barry L.
, p. 2064 - 2071 (2008/10/08)
The reaction of aromatic azides (R′N3) with MBr2(CO)3(PPh3)2 (M = Mo, W; Ph = C6H5; tol = p-CH3C6H4) in dry methylene chloride at 20°C affords MBr2(CO)3(R′N3PPh3), N2, and R′N =PPh3 (R′ = Ph, tol). The phosphazide complexes exhibit remarkable stability with respect to N2 loss. In contrast to the Mo(II) and W(II) complexes, ReCl3(CH3CN)(PPh3)2 and ReCl3(PPh2Me)3 yield ReCl4(PR3)2 upon treatment with the same aryl azides. Triclinic needles of WBr2(CO)3(tolN3PPh3) were grown from chloroform - ether and crystallized in space group C11-P1 with Z = 2, a = 13.715 (6) A?, b = 9.904 (5) A?, c = 10.397 (5) A?, α = 100.98 (2)°, β = 83.11 (2)°, and γ = 85.80 (1)°. An X-ray diffraction study at -145 (5)°C showed the complex to be monomeric and seven-coordinate. The tolyl azide had inserted into the W-P bond, forming a phosphazide ligand (tolN3PPh3) which is bound to W in a chelating fashion through the α and γ nitrogen atoms; the N3W metallacycle is nearly planar. Salient metrical parameters of the structure include the following: W-N(1) = 2.163 (4) A?, W-N(3) = 2.220 (5) A?, N(1)-N(2) = 1.279 (6) A?, N(2)-N(3) = 1.364 (6) A?, N(3)-P = 1.672 (5) A?, N(1)-C(41) = 1.423 (7) A?; N(1)-W-N(3) = 56.7 (2)°, W-N(1)-N(2) = 102.4 (3)°, W-N(3)-N(2) = 96.8 (3)°, N(1)-N(2)-N(3) = 103.8 (4)°. The full-matrix, least-squares refinement converged to R(F) = 0.028 and Rw(F) = 0.037 for 4066 unique data with Fo2 > 3σ(Fo2).
