Polarographic Studies on Mixed Ligand Complexes of Cadmium with Dl-3-(3,4-Dihydroxyphenyl)alanine and Some Dicarboxylic Acids

The reductiou of Cd(II) has been carried out polarographically in the aqueous solution of Dl-3-(3,4-dihydroxyphenyl)alanine(DOPA). The stability constants were determined for the simple Cd–DOPA system first, and then mixed-ligand complexes of cadmium with DOPA and dicarboxylic acids (oxalic and malic) have been studied. The stability constants of mixed-ligand complexes have been evaluated by the method of Schaap and McMasters. With these data the statistical and electrostatic effects have also been considered.