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(trimethylsilyl)­amido]­iron and -cobalt precursors with imidazol­(in)­ium salts. Whereas sterically less hindered salts produced the tetrahedral complexes [M­(carbene)2Cl2] (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.