Sulfide oxidation by O2: Synthesis, structure and reactivity of novel sulfide-incorporated Fe(II) bis(imino)pyridine complexes

The unsymmetrical iron(II) bis(imino)pyridine complexes [FeII(LN3SMe)(H2O)3](OTf)2 (1), and [FeII(LN3SMe)Cl2] (2) were synthesized and their reactivity with O2 was examined. Complexes 1 and 2 were characterized by single crystal X-ray crystallography, LDI-MS, 1H NMR and elemental analysis. The LN3SMe ligand was designed to incorporate a single sulfide donor and relies on the bis(imino)pyridine scaffold. This scaffold was selected for its ease of synthesis and its well-precedented ability to stabilize Fe(II) ions. Complexes 1 and 2 ware prepared via a metal-assisted template reaction from the unsymmetrical pyridyl ketone precursor 2-(OCMe)-6-(2,6-(iPr2-C6H3NCMe)-C5H3N. Reaction of 1 with O2 was shown to afford the S-oxygenated sulfoxide complex [Fe(LN3S(O)Me)(OTf)]2+ (3), whereas compound 2, under the same reaction conditions, afforded the corresponding sulfone complex [Fe(LN3S(O2)Me)Cl]2+ (4).

The unsymmetrical sulfide-incorporated bis(imino)pyridine complexes [FeII(LN3SMe)(H2O)3](OTf)2 (1) and [FeII(LN3SMe)Cl2] (2) were synthesized and characterized by X-ray crystallography. Complexes 1 and 2 react with molecular oxygen under identical conditions to afford sulfoxide and sulfone products, respectively.Figure optionsDownload as PowerPoint slide