Magnesium(I) Reduction of CO and N2 Complexes of Cummins' Molybdenum(III) Tris(anilide), [Mo(L){N(Ar')But}3] (L=CO or N2; Ar'=3,5-dimethylphenyl)

Reductions of the in situ generated CO and N-2 complexes of Cummins' molybdenum(III) tris(anilide) complex, viz. [Mo(L){N(Ar')Bu-t}(3)] (L=CO or N-2, Ar'=3,5-dimethylphenyl), using a dimagnesium(I) compound, [{((Mes)Nacnac)Mg}(2)] ((Mes)Nacnac=[HC(MeCNMes)(2)](-), Mes=mesityl), are reported. Reduction of [Mo(CO){N(Ar')Bu-t}(3)] afforded a mixture of products, three of which were isolated in low yield and crystallographically characterized. These were a molybdenum(II) tris(carbamoyl) complex, [((Mes)Nacnac)Mg{mu-(O=)[Bu-t(Ar')N]C}(3)Mo(CO)(3)] 1, a magnesium(II) carbamate, [{((Mes)Nacnac)Mg[mu-O2CN(Ar')Bu-t]}(2)] 2, and the 1,3-diamino-1,2,3-trione, Bu-t(Ar')NC3(=O)(3)N(Ar')Bu-t 3. The mechanisms of formation of these products are speculated upon. The reduction of [Mo(N-2){N(Ar')Bu-t}(3)] with [{((Mes)Nacnac)Mg}(2)], in the presence of the N-heterocyclic carbene, :C{N(Me)C(Me)}(2) TMC, gave the heterobimetallic molybdenum(II) diazenido complex, [((Mes)Nacnac)(TMC)Mg(mu-N-2)Mo{N(Ar')Bu-t}(3)] 4, in a low-moderate isolated yield. Reaction of this with chlorotrimethylsilane afforded an essentially quantitative yield of the known silyldiazenido complex, [(Me3SiN2)Mo{N(Ar')Bu-t}(3)] 5.

Automated summary

The reduction of in situ generated CO and N-2 complexes of Cummins' molybdenum(III) tris(anilide) complex using a dimagnesium(I) compound was reported. Multiple products were isolated and characterized, with speculation on the formation mechanisms. The reaction yielded various molybdenum(II) and magnesium(II) complexes.