Magnesium(I) Reduction of CO and N 2 Complexes of Cummins’ Molybdenum(III) Tris(anilide), [Mo(L){N(Ar’)Bu t } 3 ] (L=CO or N 2 ; Ar’=3,5‐dimethylphenyl)

Abstract 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{μ‐(O=)[Bu t (Ar’)N]C} 3 Mo(CO) 3 ] 1 , a magnesium(II) carbamate, [{( Mes Nacnac)Mg[μ‐O 2 CN(Ar’)Bu t ]} 2 ] 2 , and the 1,3‐diamino‐1,2,3‐trione, Bu t (Ar’)NC 3 (=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(μ‐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, [(Me 3 SiN 2 )Mo{N(Ar’)Bu t } 3 ] 5 .