Sulfide oxidation by O_2: Synthesis, structure and reactivity of novel sulfide-incorporated Fe(II) bis(imino)pyridine complexes

摘要

The unsymmetrical iron(II) bis(imino)pyridine complexes [Fe ~(II)(LN_3SMe)(H_2O)_3](OTf)_2 (1), and [Fe~(II)(LN_3-SMe)Cl_2] (2) were synthesized and their reactivity with O_2 was examined. Complexes 1 and 2 were characterized by single crystal X-ray crystallography, LDI-MS, ~1H NMR and elemental analysis. The LN_3SMe 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-(O=CMe)-6-(2,6-(~iPr _2-C_6H_3N=CMe)-C_5H_3N. Reaction of 1 with O_2 was shown to afford the S-oxygenated sulfoxide complex [Fe(LN_3S(O)Me)(OTf)]~(2+) (3), whereas compound 2, under the same reaction conditions, afforded the corresponding sulfone complex [Fe(LN_3S(O_2)Me)Cl]~(2+) (4).