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.

KEYWORDS:

• uranium(VI) complexes
• cyclic voltammetry
• redox reaction
• N
• N-dimthylformamide
• acetylacetonate
• schiff base
• multidentate ligands
• electrochemistry