Monomeric Iron(II) Hydroxo and Iron(III) Dihydroxo Complexes Stabilized by Intermolecular Hydrogen Bonding

Using the multidentate ligand bis(N-methylimidazol-2-yl)-3-methylthiopropanol (L), the mononuclear iron(II) hydroxo and iron(III) dihydroxo complexes [Fe^II(L)₂(OH)](BF₄) (1) and [Fe^III(L)₂(OH)₂](BF₄) (2) have been synthesized and characterized by X-ray diffraction and spectroscopic methods. The X-ray data suggest that the remarkable stability of the Fe−OH bond(s) in both compounds results from intermolecular hydrogen-bonding interactions between the hydroxo ligand(s) and the tertiary hydroxyl of the L ligands, which prevent further intermolecular reactions.