Oxidative Group Transfer to a Triiron Complex to Form a Nucleophilic μ3-Nitride, [Fe3(μ3-N)]-

Utilizing a hexadentate ligand platform, a high-spin trinuclear iron complex of the type (L-tbs)Fe-3(thf) was synthesized and characterized ([L-tbs](6-) = [1,3,5-C6H9-(NPh-o-(NSiBuMe2)-Bu-t)(3)](6-)). The silyl-amide groups only permit ligation of one solvent molecule to the tri-iron core, resulting in an asymmetric core wherein each iron ion exhibits a distinct local coordination environment. The triiron complex (L-tbs)Fe-3(thf) rapidly consumes inorganic azide ([N-3]NBu4) to afford an anionic, trinuclear nitride complex [(L-tbs)Fe-3(mu(3)-N)]NBu4. The nearly C-3-symmetric complex exhibits a highly pyramidalized nitride ligand that resides 1.205(3) angstrom above the mean triiron plane with short Fe-N (1.871(3) angstrom) distances and Fe-Fe separation (2.480(1) angstrom). The nucleophilic nitride can be readily alkylated via reaction with methyl iodide to afford the neutral, trinuclear methylimide complex (L-tbs)Fe-3(mu(3)-NCH3). Alkylation of the nitride maintains the approximate C-3-symmetry in the imide complex, where the imide ligand resides 1.265(9) angstrom above the mean triiron plane featuring lengthened Fe-N-imide bond distances (1.892(3) angstrom) with nearly equal Fe-Fe separation (2.483(1) angstrom).