Electrochemical and spectroscopic investigations of uranium(III) with N,N,N′,N′-tetramethylmalonamide in DMF

In order to investigate the electrode reaction of negative electrolyte, U(III)/U(IV), of the all-uranium redox-flow battery proposed by us, we investigated the magnetic susceptibility, spectroscopy and electrode reactions of U(III) and U(IV) complexes with N,N,N′,N′-tetramethylmalonamide (TMMA). The effective magnetic moment for the U(III) complex (1.95μ_B/atomU) is significantly smaller than the theoretical moment for free U³⁺ ion, and this may indicate the itinerant nature of U(III) due to the coordination of TMMA. In N,N-dimethylformamide (DMF), the energy levels due to f-f transitions was only slightly perturbed from those of uranium(III) perchlorate in DMF. The U(III)/U(IV) redox potential of U(III)-TMMA complex shifted negatively from that of uranium(III) perchlorate.