Coordination modes of histidine- or methioninehydroxamic acids in copper(II) mixed-ligand complexes with ethylenediamine in aqueous solution

Abstract: The stability constants and coordination modes of the mixed-ligand complexes formed by copper(II) ion and ethylenediamine as a primary ligand and methioninehydroxamic acid (Metha) or histidinehydroxamic acid (Hisha) as a secondary ligand L were determined by potentiometric titration, UV–Vis and EPR spectroscopy. The obtained results suggest the formation of mixed-ligand species in basic solution with 4N coordination – both amine and hydroxamic nitrogens of Metha or Hisha (NH2, Nha) and two amine nitrogens of en (2×NH2) in the equatorial plane. [Copyright &y& Elsevier]