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 [Fe-II(LN3SMe)(H2O)(3)](OTf)(2) (1), and [Fe-II(LN3SMe)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, H-1 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-(O=CMe)-6-(2,6-(Pr-i(2)-C6H3N=CMe)-C5H3N. Reaction of 1 with O-2 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(O-2)Me)Cl](2+) (4). (C) 2013 Elsevier Ltd. All rights reserved.