Die Umsetzungen von MoNCl3 bzw. WNCl3 mit Lithium-Diphenylamid in Tetrahydrofuran fuhren zu den monomeren Nitridokomplexen MN(NPh2)3 mit KZ = 4 an den Metallatomen. Bei Anwesenheit von Lithium-n-butyl reagiert LiNPh2 mit WNCl3 auch zu dem tetrameren, Wolfram(V) und Wolfram(VI) enthaltenden Nitridokomplex [W4N4(NPh2)6(OnC4H9)2]. Die Verbindungen werden durch ihre IR-Spektren, zum Teil durch die 1H- und 13C-Kernresonanzspektren sowie durch Rontgenstrukturanalysen charakterisiert.
MoN(NPh2)3: Raumgruppe P1, Z = 2, 4060 unabhangige beobachtete Reflexe, R = 3,1%. Gitterabmessungen bei 20°C: a = 956,2(4); b = 1015,9(2); c = 1598,1(3) pm; α = 79,06(2)°; β = 85,67(3)°; γ = 82,57(3)°. Die Verbindung bildet monomere Molekule mit Bindungslangen MoN 163,4 pm und MoNPh2 von im Mittel 199,2 pm.
[W4N4(NPh2)6(OnC4H9)2]: Raumgruppe P21/n, Z = 2, 1903 beobachtete unabhangige Reflexe, R = 3,9%. Gitterabmessungen bei 19°C: a = 1 582,2(3); b = 1 182,4(2); c = 2 053,3(4) pm; β = 103,77(2)°. Die Verbindung bildet zentrosymmetrische Molekule, deren zentrale W—W-Hantel (Bindungslange 253,5 pm) uber die Nitridoliganden zweier WN2(NPh2)2-Einheiten mit T-formiger Anordnung der N-Atome verknupft ist.
Stericly Shielded Nitrido Complexes of Molybdenum and Tungsten. The Crystal Structures of [MoN(NPh2)3] and [W4N4(NPh2)6(OnC4H9)2]
The reactions of MoNCl3 and WNCl3, respectively, with lithium diphenylamide in tetrahydrofurane produce the monomeric nitrido complexes MN(NPh2)3 with CN = 4 at the metal atoms. In the presence of lithium-n-butyl LiNPh2 and WNCl3 also form the tetrameric nitrido complex [W4N4(NPh2)6(OnC4H9)2] which contains WV and WVI. The compounds are characterized by their i.r. spectra, by X-ray structural analysis, and, partially, by 1H and 13C n.m.r. spectroscopy.
MoN(NPh2)3: Space group P1, Z = 2, 4060 observed independent reflexions, R = 0.031. Lattice dimensions at 20°C: a = 956.2(4) pm, b = 1 015.9(2) pm, c = 1 598.1(3) pm; α = 79.06(2)°, β = 85.67(3)°, γ = 82.57(3)°. The compound forms monomeric molecules with MoN bond lengths of 163.4 pm and mean MoNPh2 distances of 199.2 pm.
[W4N4(NPh2)6(OnC4H9)2]: Space group P21/n, Z = 2, 1903 observed independent reflexions, R=0.039. Lattice parameters at 19°C: a = 1582.2(3) pm, b = 1182.4(2) pm, c = 2053.3(4) pm; β = 103.77(2)°. The compound forms centrosymmetric molecules, in which the central W–W dumb-bell (bond length 253.5 pm) is linked by the nitrido ligands of two WN2(NPh2)2=units in a T shaped order of the N-atoms.
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