Reactions of cobalt(III) compounds with some free radicals derived from uracil
Abstract
Reactions of CoIII complexes with the transient adducts of uracil (U), viz. U–, UH and UOH, have been studied by means of γ-radiolysis of uracil in the presence of CoIIIEDTA and CoIIINTA (where EDTA is ethylenediamine tetra-acetate and NTA is nitrilotriacetate). The U– and UH radicals formed by the reactions of e–aq and H with uracil reduce CoIII to CoII complexes. The UOH radicals, however, do not reduce the CoIII complexes although such reductions have been observed with CuII and FeIII analogues as reported earlier. The absence of such electron transfer from UOH to CoIII could not be explained on the basis of the redox potential of the CoIIIEDTA/CoIIEDTA couple, which was 0.38 V. However, this apparent anomaly has been explained on the basis of the individual structures of the respective complexes.