Aminolysis of Bis[bis(trimethylsilyl)amido]iron and -cobalt as a Versatile Route to N-Heterocyclic Carbene Complexes

A range of new N-heterocyclic carbene complexes of iron(II) and cobalt(II) have been conveniently obtained by the aminolysis of bis[bis(trimethylsily)amido]iron and -cobalt precursors with imidazol(in)ium salts. Whereas sterically less hindered salts produced the tetrahedral complexes [M-(carbene)(2)Cl-2] (M = Fe), bulkier salts gave the three-coordinate [M(carbene){N(SiMe3)(2)}Cl] (M = Fe, Co), which serve as versatile precursors to a range of derivatives; mechanistic aspects of the reaction are discussed.