M. Mashihara, T. Ando, I. Murase
Mar 1, 1973
Citations
0
Influential Citations
5
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
N,N′-Ethylenebis(aminomalonic) acid (EAMA) has been synthesized, and its acid dissociation constants and the stability constants of its alkaline earth metal complexes were determined potentiometrically at 25°C in a medium of ionic strength of 0.10 (KNO3) with the following results: pK1=2.1, pK2=2.72, pK3=6.56, pK4=9.69; logKMY and logMMHY for Ca(II) respectively, 5.45 and 2.02; for Mg(II) respectively 4.93 and 1.80. The exact stability constants of Cu(II) and Ni(II) chelates of this ligand were not obtained on account of its decomposition in low pH solution, but the order of relative stability has been established. From a comparison of the stability of Ca(II) and Mg(II) chelates with those of the analogous complexane, the function of the malonate group in the chelate formation has been discussed. Zn(II) and Co(II) chelates of this ligand have been obtained and their probable structures are proposed.