ic950919x_si_002.pdf (1.03 MB)

Syntheses, Structures, and Reactivity of a Series of (Pentamethylcyclopentadienyl)molybdenum(V) and -tungsten(V) Imido Complexes

Download (1.03 MB)
journal contribution
posted on 27.03.1996, 00:00 by Katrin Köhler, Herbert W. Roesky, Axel Herzog, Heinz Gornitzka, Alexander Steiner, Isabel Usón
Reactions of the (pentamethylcyclopentadienyl)molybdenum(V) and -tungsten(V) tetrachlorides (η5-C5Me5)MCl4 (M = Mo, W) with the primary amines RNH2 (R = t-Bu, i-Pr, C6F5, and 2,6-(i-Pr)2C6H3) lead to the formation of the imido complexes [(η5-C5Me5)M(NR)Cl2] (3ah). X-ray structure analyses of 3a, 3c, and 3e reveal their monomeric nature. 3c and 3e crystallize in the monoclinic space group P21/c with the lattice parameters a = 15.171(3) Å, b = 7.615(2) Å, c = 14.758(3) Å, β = 90.29(3)°, and V = 1704.9(7) Å3 for 3e and a = 10.4502(7) Å, b = 10.6897(8) Å, c = 15.915(2) Å, β = 94.342(8)°, and V = 1772.7(3) Å3 for 3c. 3a crystallizes in the orthorhombic space group P212121 with a = 8.6040(10) Å, b = 12.0490(10) Å, c = 17.020(2) Å, and V = 1764.5(3) Å3. The metal−nitrogen distances of these 17-electron complexes (1.719(3) Å for 3a, 1.716(12) Å for 3e, and 1.748(2) Å for 3c) correspond to a triple bond. (η5-C5Me5)W(NC6F5)Cl2 (3g) decomposes in the presence of air to the half-sandwich tungsten(VI) imido complex (η5-C5Me5)W(NC6F5)Cl3 (4) and a green solid. Further hydrolysis of 3g results in the dinuclear tungsten(VI) oxo complex [(η5-C5Me5)WO2]2(μ-O).C6F5NH2 (5) with a linear W−O−W bridge. The complexes have been characterized by X-ray diffraction. 4 crystallizes in the triclinic space group P1̄, with a = 7.3843(1) Å, b = 11.529(2) Å, c = 11.558(2) Å, α = 77.38(2)°, β = 80.15(2)°, γ = 79.88(2)°, and V = 936.2(3) Å3; 5 crystallizes in the monoclinic space group P21/n, with a = 1.3246(3) Å, b = 1.0042(3) Å, c = 1.4102(3) Å, β = 104.37(3)°, and V = 1.8173(6) Å3.

History