Copper(II) complexes of ligands containing both aminocarboxylate and aminophosphinate moieties

Abstract

Spectroscopic (visible, e.s.r., and n.m.r.) and pH-metric studies were made of the proton and copper(II) complexes of N-[(aminomethyl)hydroxophosphorylmethyl]-pyroglutamic acid (-5-oxo-L-proline) and -leucine at 25 °C and l= 0.2 mol dm^–3(KCl). It was found that both ligands have an ambidentate character; complex formation starts at the amino acid end of the molecules then, at higher pH, the aminophosphinate moiety also takes part in co-ordination. The bidentate co-ordination ability of the leucine residue, and the monodentate co-ordination of the pyroglutamate residue, make the former ligand much more able to bind the metal ion.