COMPLEXES OF CU(II) WITH D-ALDONIC AND D-ALDURONIC ACIDS IN AQUEOUS-SOLUTION

A quantitative study of the equilibria involved in the interaction of Cu(II) ion With D-glucoheptonic, D-gluconic, D-galactonic, D-ribonic, D-glucuronic, and D-galacturonic acids in aqueous medium has been carried out by means of potentiometric measurements of hydrogen ion concentrations at a constant temperature of 20-degrees-C and an ionic strength of 0.10 (NaNO3). The equilibrium data were processed with the FORTRAN computer program BEST. It was found that Cu(II) interacts with D-aldonic acids to form 1:1, 2:2, and 1:2 (M/L) complexes. The copper(II) complexes with D-galacturonic and D-glucuronic acids are considerably weaker than those of D-aldonic acid. Possible structures of the complex species formed are discussed.