Thermally Induced Stoichiometric and Catalytic O‐Atom Transfer by a Non‐Heme Iron(<scp>III</scp>)–Nitro Complex: First Example of Reversible {Fe–NO}⁷↔Fe^III‐NO₂ Transformation in the Presence of Dioxygen

Abstract

The non-heme iron(III) complex [(PaPy3)Fe(NO2)](ClO4) (1) transfers oxygen in the temperature range 45–65 °C to PPh3 to afford OPPh3 in MeCN. The product, [(PaPy3)Fe(NO)](ClO4), a {Fe-NO}7 species, reverts rapidly back to 1 in the presence of dioxygen, thus making the system catalytic (see scheme). Formation of an oxo-bridged species terminates the oxo-transfer process (PaPy3H=N-[N,N-bis(2-pyridylmethyl)aminoethyl]-2-pyridinecarboxamide).