Collect. Czech. Chem. Commun. 1983, 48, 2777-2784

Study of the formation of complexes of 2-hydroxy-1,3-propanediamine-N,N,N',N'-tetraacetic acid with Zn(II), Cd(II) and Pb(II) ions using NMR spectroscopy

Pavol Novomeský, Pavol Balgavý and Jaroslav Majer

Department of Analytical Chemistry, Pharmaceutical Faculty, Comenius University, 832 32 Bratislava


2-Hydroxy-1,3-propanediamine-N,N,N',N'-tetraacetic acid (HPDTA) forms complexes of the ML type with Zn(II) and Cd(II) ions in the pDH ranges 5.0-11.5 and 7.3-8.6, respectively. In these complexes, there are coordinated oxygen atoms of four carboxylate groups and nitrogen atoms of two amino-groups. Formation of the Pb2L type complex was observed in the pDH region 5.9-11.5. HPDTA is a heptadentate ligand in this complex. The two glycinate rings correspond to one Pb(II) ion and are nonequivalent. During formation of the hydroxocomplexes of Pb2L and CdL in alkaline solutions, the HPDTA carboxylate groups become substituted by OH- ion in the coordination sphere of the metal ion.