Imide Transfer Properties and Reactions of the Magnesium Imide ((THF)MgNPh)6: A Versatile Synthetic Reagent

Abstract

Imide transfer properties of ((THF)MgNPh)₆ (1) and the synthesis of the related species {(THF)MgN(1-naphthyl)}₆·2.25THF (2), via the reaction of dibutylmagnesium with H₂N(1-naphthyl), in a THF/heptane mixture are described. Treatment of 1 with Ph₂CO, 4-Me₂NC₆H₄NO, t-BuNBr₂ (3), PCl₃, or MesPCl₂ (Mes = 2,4,6-Me₃C₆H₂-) leads to the isolation of Ph₂CNPh (4), 4-Me₂NC₆H₄NNPh (5), t-BuNNPh (6), (PhNPCl)₂ (7), or (MesPNPh)₂ (8) in moderate yield. Reaction between 1 and GeCl₂·dioxane, SnCl₂, or PbCl₂ affords the M₄N₄ (M = Ge, Sn, Pb) cubane imide derivative (GeNPh)₄ (9), [(SnNPh)₄·{MgCl₂(THF)₄}]_∞ (10), (SnNPh)₄·0.5PhMe (11), or (PbNPh)₄·0.5PhMe (12). Interaction of 1 with Ph₃PO, (Me₂N)₃PO, or Ph₂SO furnishes the complex (Ph₃POMgNPh)₆ (13), {(Me₂N)₃POMgNPh}₆·2PhMe (14), or (Ph₂SOMgNPh)₆ (15). The addition of 3 equiv of MgBr₂ to 1 gives 1.5 equiv of ((THF)Mg)₆(NPh)₄Br₄ (16) in quantitative yield, whereas treatment of 16 with 4 equiv of 1,4-dioxane is an alternative synthetic route to 1. Compounds 2, 3, 9, 10, and 14 were characterized by X-ray crystallography. The reactions demonstrate that 1 is a versatile and useful reagent for the synthesis of a variety of main group imides. Crystal data at 130 K with Mo Kα (λ = 0.710 73 Å) radiation for 3 or Cu Kα (λ = 1.541 78 Å) radiation for 2, 9, 10, and 14: 2, C₉₃H₁₀₈Mg₆N₆O_7.25, a = 28.101(7) Å, b = 35.851(7) Å, c = 36.816(7) Å, Z = 2, space group Fddd, R = 0.068 for 3500 (I > 2σ(I)) data; 3, C₄H₉Br₂N, a = 6.682(2) Å, b = 10.834(3) Å, c = 11.080(3) Å, α = 66.25(2)°, β = 89.88(2)°, γ = 82.53(2)°, Z = 4, space group P1̄, R = 0.038 for 2043 (I > 2σ(I)) data; 9, C₂₄H₂₀Ge₄N₄, a = 10.749(2) Å, b = 12.358(3) Å, c = 35.818(7) Å, Z = 8, space group Pbca, R = 0.040 for 2981 (I > 2σ(I)) data; 10, C₄₀H₅₂Cl₂MgN₄O₄Sn₄, a = 12.770(3) Å, b = 13.554(3) Å, c = 25.839(5) Å, Z = 4, space group P2₁2₁2₁, R = 0.040 for (I > 2σ(I)) data; 14, C₈₆H₁₅₄Mg₆N₄O₆P₆, a = 22.478(4) Å, b = 16.339(3) Å, c = 29.387(6) Å, Z = 4, space group Pbcn, R = 0.081 for 4696 (I >2σ(I)) data.