RsvH3 is deprotonated by CH3ONa as a Brønsted base, the spectrum is attributed to RsvH2 -. On the other hand, the spectrum of RsvH3 in the presence of saturated O2 (4.8 × 10 -3 mol dm -3 ) has disappeared, showing the appearance of a small absorption band centered at 235 nm at applied cathodic potentials over -1.3 V (red bold) corresponding to electrogeneration of O2 •-. This spectral change demonstrated that the product is not RsvH2 -, implying that RsvH2 -decomposed through the subsequent reactions. By analogy with the CV and ESR results, the initial PT (Equation ( )) and the following ET between HO2 • and RsvH2 -(Equation ( )) rapidly undergo base-catalyzed oxidation, forming RsvH2 • as shown by the diagonal of the rectangle in Figure .