Binding ability of aminophosphonates containing imidazole and pyridine as additional donor systems

The paper describes solution studies of Cu(II) and Ni(II) complexes of new N-substituted imidazole-2-yl(amino)methylphosphonates. The presence of the 2-imidazole ring makes studied phosphonates very efficient ligands, with nickel(II) ions chelation much more effective than by the previously designed 4-imidazole analogs. Introduction of ortho-pyridine as additional donor in the side chain further increases the binding ability. The effectiveness of this compound is due to chelation of metal ions through imidazol, imino and pyridine nitrogen donors.