Synthesis and characterization of mononuclear hydroxamato and hydroximato complexes of iron(III) based on the tris-(2-pyridylmethyl)amine ligand.

The reaction of acetohydroxamic (CH3C(O)-NHOH), benzhydroxamic acid (PhC(O)-NHOH) or 1-hydroxypyridin-2(1H)-one (pyrC(O)-NOH) in the presence of tris-(2-pyridylmethyl)amine (TPA), sodium methoxide and an iron(III) salt yields the mononuclear complexes [Fe(TPA)(CH3C(O)-NHO)]2+ (), [Fe(TPA)(PhC(O)-NHO)]2+ () and [Fe(TPA)(pyrC(O)-NO)]2+ (). The hydroxamato complexes and are easily converted to their hydroximato form [Fe(TPA)(CH3C(O)=NO)]+ () and [Fe(TPA)(PhC(O)=NO)]+ () by addition of base. The complexes described were characterized by UV-vis spectroscopy, EPR and cyclic voltammetry, as well as single-crystal X-ray crystallography for and .