Kinetics and mechanism of electroreduction of palladium(II) bisethylenediamine complexes on a dropping mercury electrode

Kinetics of electroreduction of complexes Pd(en)(2)(2+) (2 x 10(-5) M) on a dropping mercury electrode is studied in solutions with various concentrat ions of ethylenediamine and supporting electrolytes (NaF, NaClO4) at pH 4.5 -11 and different instantaneous current recording times. Diffusion coeffici ents for reducing complexes and kinetic parameters of the slow electrochemi cal stage are determined. The concentration of supporting electrolytes is f ound to affect the half-wave potential, which points to an inner-sphere mec hanism of electrochemical stage at supporting electrolyte concentrations of 0.005 to 0.03 M and to a predominantly outer-sphere mechanism at higher co ncentrations.