MECHANISM OF THE ELECTROCHEMICAL OXIDATION OF ZERO VALENT PALLADIUM COMPLEXES

Within long times scales, the electrochemical oxidation of Pd(O)(PPh3) (4) proceeds through an ECE-like two-electron process to afford two ca tionic palladium(II) complexes in equilibrium: Pd(II)(PPh3)(2)(BF4)(2) and Pd(II)(PPh3)(3)(BF4)(2), whose relative concentrations depend on the triphenylphosphine concentration. At short time scales, one-electr on oxidation affords a transient cationic palladium(I) complex involve d in a fast follow-up endergonic equilibrium which is believed to cons ist in a geometrical rearrangement (tetrahedral to square planar), mos t probably induced by the solvent.