Transient Intermediate Produced from 5-Aminouracil in Reaction with Dichloride Anion Radical

Abstract

Abstract A transient absorption, which is relatively long-lived, was found in a flash photolysis of aqueous potassium chloride containing 5-aminouracil. The transient absorption with a peak at about 335 nm was assigned to an intermediate produced from 5-aminouracil through a one-electron oxidation by dichloride anion radical. For the intermediate, a possible structure is proposed to explain its long life-time. On the basis of the transient absorption, a determination of the rate constant for the reaction of 5-aminouracil with dichloride anion radical was carried out by use of a competition kinetics. The value of (2.9±0.2)×108 dm3 mol−1 s−1 was obtained as the rate constant on the basis of rate constants of several reference compounds. By comparing the values obtained by the competition method with those estimated by a direct analysis of the decay rate of dichloride anion radical, the validity of the competition method was examined.