Synthesis, Characterization, and Dioxygen Reactivity of Tetracarboxylate-Bridged Diiron(II) Complexes with Coordinated Substrates

The synthesis and characterization of [Fe₂(μ-O₂CAr^Tol)₄L₂] complexes, where L is benzylamine or 4-methoxybenzylamine (BA^p-OMe), are described. The reaction of the latter diiron(II) complex with dioxygen at −78 °C affords a metastable mixed-valent Fe(II)Fe(III) green intermediate. When O₂ is introduced at ambient temperature, N-dealkyation occurs to yield anisaldehyde, eliminating N-oxidation as a viable pathway for the reaction. Use of [Fe₂(μ-O₂CAr^Tοl)₄(α-d₁-BA^p-OMe)₂] allowed a deuterium kinetic isotope of ∼3 to be determined.