DramaticallyAccelerated Selective Oxygen-Atom Transferby a Nonheme Iron(IV)-Oxo Complex: Tuning of the First and SecondCoordination Spheres

摘要

The new ligand N3Py^amideSR and its Fe^II complex [Fe^II(N3Py^amideSR)](BF4)2 (>1) are described. Reaction of >1 with PhIO at −40 °C gives metastable [Fe^IV(O)(N3Py^amideSR)]²⁺ (>2), containing a sulfide ligand and a single amide H-bond donor in proximity to the terminal oxo group. Direct evidence for H-bonding is seen in a structural analogue, [Fe^II(Cl)(N3Py^amideSR)](BF4)2 (>3). Complex >2 exhibits rapid O-atom transfer (OAT) toward external sulfide substrates, but no intramolecular OAT. However, direct S-oxygenation does occur in the reaction of >1 with mCPBA, yielding sulfoxide-ligated [Fe^II(N3Py^amideS(O)R)](BF4)2 (>4). Catalytic OAT with >1 was also observed.