Oxidative Ligand Rearrangement Due to Incipient Aminyl Radicals in the Oxidation of Iron(II) Species with Dioxygen

The ferrous complex [(L 1 )Fe II –THF] – , featuring the trisamido‐amine ligand [(RNC 6 H 4 ) 3 N] 3– , where R is the electron‐rich 4‐ t Bu‐Ph moiety, can undergo a one‐electron oxidation by dioxygen to afford the corresponding [(L 1 )Fe III –OH] – complex, and a parallel two‐electron oxidation to generate the antiferromagnetically coupled diferric μ‐oxo compound [(L 1 re–1 )Fe–O–Fe(L 1 re–1 )]. The latter compound possesses a ligand that exhibits oxidative rearrangement and retention of the oxidation equivalent in a o ‐diiminobenzosemiquinato moiety as a π radical. Ligand oxidation is perceived to initiate at an amido residue leading to formation of an electrophilic, metal‐bould aminyl radical that undergoes an 1,4‐(N‐to‐N) aryl migration reaction.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)