KINETICS AND MECHANISM OF THE ELECTROREDUCTION OF PALLADIUM(II) BISIMINODIACETATE COMPLEXES AT THE DROPPING MERCURY-ELECTRODE

The kinetics of electroreduction of Pd(II) bis-iminodiacetate complexe s, Pd(ida)(2)(2-), is studied at the dropping mercury electrode in NaC lO4 and NaF supporting electrolytes in the pH range 3.2 to 10.5. The c omplexes are shown to reduce irreversibly, with the half-wave potentia l being independent of both pH and the free ligand concentration. The limiting current is found to be of diffusion nature, and the slow two- electron electrochemical stage is shown to involve the Pd(ida)(2)(2-) complexes adsorbed on mercury. Adsorption of the supporting electrolyt e anions on the mercury electrode in the region of positive charges un der study retards reduction of these complexes.