Stability and Structure of Ethylenedinitrilopoly(methylphosphonate) Complexes of the Divalent Transition Metal Ions in Aqueous Solution

The formation and protonation of the complexes of a series of ethylenedinitrilopoly(methylphosphonic acids) (EDMP) [(Me)2 - p(H2O3PCH2)pNC2H4N(Me)2 - q(CH2PO3H2)q, p = 0–2, q = 1–2] with divalent transition metal ions (M = Mn2+, Co2+, Ni2+, Cu2+, Zn2+ or Cd2+) were investigated by means of potentiometry and 31P NMR spectroscopy at 25.0 °C. The complex formation constants and protonation constants of these complexes were determined by pH titration. The 31P NMR spectra of zinc and cadmium complexes were measured as a function of the pH, and the 31P NMR chemical shifts of each chemical species were evaluated by using the equilibrium constants determined by pH titration. The results for EDMP complexes were compared with those of aminopoly(methylphosphonate) (NMP) [(CH3)3 - rN(CH2PO3H2)r, r = 1 – 3] complexes and alkaline earth metal EDMP complexes. The stability constants of the metal complexes increase upon increasing the number of the phosphonate groups and are around the same between the EDMP and NMP compl...

[1]  Y. Pétillot,et al.  Complexation of alkali metal and tetramethylammonium ions with polyacids. pH-Metry consequences , 1999 .

[2]  K. Hashimoto.  Labelling of aminomethylenephosphonate derivatives with generator-produced , and a study of their stability , 1999 .

[3]  G. Hefter,et al.  Potentiometric and computer studies of yttrium-EDTMP☆ , 1998 .

[4]  K. Sawada,et al.  Protonation Behavior and Intramolecular Interactions of α, ω-Alkanediaminepolymethylenepolyphosphonates , 1997 .

[5]  Toshio Suzuki,et al.  Protonation equilibria of nitrilotris(methylenephosphonato)-and ethylenediamine-tetrakis(methylenephosphonato)-complexes of scandium, yttrium, and lanthanoids , 1991 .

[6]  Toshio Suzuki,et al.  Complex formation of aminopolyphosphonates. 2. Stability and structure of nitrilotris(methylenephosphonato) complexes of the divalent transition metal ions in aqueous solution , 1989 .

[7]  Toshio Suzuki,et al.  Complex formation of amino polyphosphonates. 1. Potentiometric and nuclear magnetic resonance studies of nitrilotris(methylenephosphonato) complexes of the alkaline-earth-metal ions , 1987 .

[8]  G. Choppin,et al.  Nuclear magnetic resonance study of ethylenediaminetetrakis(methylenephosphonic acid) and some metal complexes , 1983 .

[9]  A. Martell,et al.  Gallium complexes of multidentate ligands in aqueous solution , 1980 .

[10]  E. Rizkalla,et al.  Metal chelates of phosphonate-containing ligands-III Analytical applications of N,N,N',N'-ethylenediaminetetra(methylenephosphonic) acid. , 1980, Talanta.

[11]  E. Rizkalla,et al.  Metal chelates of phosphonate-containing ligands-I Stability of some N,N,N',N'-ethylenediaminetetra(methylenephosphonic) acid metal chelates. , 1979, Talanta.

[12]  A. Martell,et al.  Equilibriums of ethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic) acid with copper(II), nickel(II), cobalt(II), zinc(II), magnesium(II), calcium(II), and iron(III) ions in aqueous solution , 1976 .

[13]  M. I. Kabachnik,et al.  Synthesis and complex-forming properties of nitrogen-methylated ethylenediamino-N,N′-dimethyl- and ethylenediamino-N,N′-diethylphosphonic acids , 1976 .

[14]  K. S. Rajan,et al.  New Multidentate Ligands. III. Amino Acids Containing Methylenephosphonate Groups1 , 1965 .

[15]  L. P. Bondareva,et al.  THERMOCHEMISTRY OF THE REACTION OF COMPLEXING POLYELECTROLYTES WITH METAL CATIONS , 1999 .

[16]  Peter V. Coveney,et al.  Molecular modelling of the mechanism of action of phosphonate retarders on hydrating cements , 1996 .