Abstract:
The reactions of the electrogenerated superoxide ion with fluorinated β-ketoamines and their nickel and palladium chelates in N,N-dimethylformamide containing tetraethylammonium perchlorate have been investigated. Using dc and commutated polarography an ECE-type mechanism was found to be operative, the substrate acting as the protonating agent towards the superoxide ion. The pseudo-first- and the second-order rate constants for the {A figure is presented} protonation were estimated by fitting ik/id values to the ik/id vs. log kt working curves (ik/id is the ratio of the limiting current for oxygen reduction with added substrate to the corresponding limiting current without added substrate). The second-order rate constants for the complexes were found to correlate with pKa values of the amino groups of the corresponding ligands. The mechanism of {A figure is presented} protonation by the ligands was shown to be complicated. © 1984.