Polynuclear palladium complexes with biogenic polyamines: AFM and voltammetric characterization

The voltammetric study of Spm and Spd showed that these biogenic polyamines undergo an irreversible and pH-dependent oxidation. In acid medium the polyamines are fully protonated, rendering their oxidation more difficult. With increasing pH the oxidation potential for both Spm and Spd is shifted to less positive values, indicating a greater ease of oxidation in alkaline medium. The Pd(II)-Spm and Pd(II)-Spd complexes dissociate at high negative or high positive potentials. The application of a positive potential induced the oxidation of these Pd complexes and the formation of mixed layers of palladium oxides, Spm/Spd and Pd(II)-Spm/Pd(II)-Spd.