The stability constants of cobalt(III) chelates of polyaminopolycarboxylic acids

Abstract

The cobalt(III) chelates of ethylenediaminetetra-acetic acid, iminodiacetic acid, NN′-bis-(2-aminoethyl)ethylenediaminehexa-acetic acid, and N′-hydroxyethylenediamine-NNN′-triacetic acid have been prepared and analysed, and the stability constants measured over a pH range. Reproducible redox potentials were obtained by use of a gold-plated, gold indicator electrode in conjunction with a pH meter. The relative values of the stability constants were in agreement with those expected from the chemical structures of the chelates.