Oxidation of Sulfide, Phosphine, and Benzyl Substrates Tethered to N-Donor Pyridine Ligands in Carboxylate-Bridged Diiron(II) Complexes

Substituted pyridines were employed to prepare a series of terphenylcarboxylate-bridged diiron(II) compounds to mimic aspects of the chemistry at the active sites of bacterial multicomponent monooxygenases, including soluble methane monooxygenase (sMMO) and toluene monooxygenase (ToMO). Complexes of general formula [Fe₂(O₂CAr^Tol)₄L], L = 2, 3, or 4-pyridyldiphenylphosphine, 2-pyridylphenylsulfide, or 2-benzylpyridine and Ar^Tol = 2,6-di(p-tolyl)benzoate, were synthesized and characterized by X-ray crystallography. Upon exposure of these compounds to dioxygen, ligand oxidation ensued and, in one case, proceeded catalytically.