Reactions of carbonate radical with cobalt(II) aminopolycarboxylates

Reactions of carbonate (CO₃^–·) and bicarbonate (HCO₃^·) radicals generated by photolysis of a carbonate or bicarbonate solution at pH 11.2 and 8.5, respectively, with Co(II) complexes of iminodiacetic acid (IDA) and ethylenediaminetetraacetic acid (EDTA) have been studied. The rate constants for the reactions were in the order of 10⁶–10⁷ dm³mol^–1s^–1. From the time-resolved spectroscopy of the products formed after reaction of CO_3·^–· or HCO₃^·, it is observed that CO₃^–· or HCO₃^· oxidize the metal center to its higher oxidation state.