Electrochemical Studies on [UO2(DMF)5](CIO4)2, UO2(acac)2DMF, and UO2(salen)DMF (DMF=N, N-dimethylformamide, acac=acetylacetonate, salen=N, N′-disalicylideneethylenediaminate) Complexes in DMF

Abstract

Electrochemical studies on [UO2(DMF)5]2+, UO2(acac)2DMF, and UO2(salen)DMF (DMF=N, N-dimethylformamide, acac=acethylacetonate, and salen=N,N′-disalicylidene-ethylenediaminate) complexes in DMF containing tetrabutylammonium perchlorate as supporting electrolyte have been carried out by using cyclic voltammetry to compare the stabilities of the reduction products of U(Vi) complexes with unidentate or multidentate ligands. The [UO2(DMF)5]2+, UO2(acac)2DMF, and UO2(salen)DMF complexes were found to be quasi-reversibly reduced to U(V) species. The formal redox potentials (E°, vs. ferrocene/ferrocenium) for the U(Vi)/U(V) couple were determined to be -0.89 V for [UO2(DMF)5]2+, -1.47 V for UO2(acac)2DMF, and -1.67 V for UO2(salen)DMF. The U(V) species formed in the reduction of [UO2(DMF)5]2+ complex is not stable and further reduced to UO2, while those generated in the reduction of UO2(acac)2DMF and UO2(salen)DMF complexes can exist stably in DMF.