Electrochemical redox reactions of uranium(VI) complexes with multidentate ligands in dimethyl sulfoxide

Abstract

Abstract Electrochemical reactions of UO2(β-diketonato)2-dmso, UO2(trop)2dmso, UO2(sap)(dmso)2, and UO2(salen)dmso (dmso = dimethyl sulfoxide, β-diketonate = benzoylacetonate (ba), benzoyltrifluoroacetonate (btfa), and thenoyltrifluoroacetonate (ttfa), trop = tropolonate, sap = 2-salicylidenaminophenolate, and salen = N , N´-disalicylidenethylenediaminate) complexes in dmso solutions containing tetrabutylammonium perchlorate as a supporting electrolyte have been studied with cyclic voltammetry. These uranyl(VI) complexes were found to be reduced quasi -reversibly to U(V) species. The formal redox potentials (E°, vs . ferrocen/ferrocenium) for U(VI)/U(V) couples were determined to be -1.416 V for UO2(ba)2dmso, -1.073 V for UO2(btfa)2dmso, -1.082 V for UO2(ttfa)2dmso, -1.379 V for UO2(trop)2dmso, -1.500 V for UO2(sap)(dmso)2, and -1.602 V for UO2(salen)dmso. Furthermore, the resulting U(V) complexes, [UO2(btfa)2dmso]-, [UO2(ttfa)2dmso]-, and [UO2(salen)dmso]-, were found to be able to exist stably in dmso solutions.