Quenching of excited uranyl ion by metal carbonyls in aprotic solvents

Abstract

The nature of the quenching of the luminescent state of uranyl ion by a number of metal carbonyls, [M(CO)_n], has been studied in aprotic solvents. Flash photolysis and e.s.r. and i.r. spectroscopy show that the quenching process takes place with concomitant formation of the paramagnetic reactive intermediate, [M(CO)_n]⁺, and the [UO₂]⁺ ion. The bimolecular quenching constants k_Q are related to the free energy change of the electron-transfer process; thus values of log k_Q are correlated with the oxidation potentials of [M(CO)_n]. The primary photoproducts are involved subsequently in an irreversible redox process with formation of U^IV and M^z+ ions.