COMPLEXES OF AMINOPHOSPHONATES .8. COPPER(II) COMPLEXES OF N-(PHOSPHONOMETHYL)AMINO ACIDS AND RELATED-COMPOUNDS

pH-Metric and spectroscopic (absorption and EPR) studies were made of the proton and copper(II) complexes of a series of ambidentate N-(phos phonomethyl)amino acids which contain both iminocarboxylate and iminop hosphonate moieties. The stoichiometries and stability constants of th e complexes formed were determined at 25-degrees-C and at an ionic str ength of 0.20 mol dm-3 (KCl). Stability data and spectroscopic measure ments revealed that the first ligand molecule co-ordinates very strong ly, forming a tridentate equimolar species, while the second one binds to the metal ion much less effectively in an axial-equatorial mode. T he results were compared with those on the carboxylate analogues imino diacetic acid and nitrilotriacetic acid.