U(IV) Chloride Complexes Isolated from Acidic Aqueous Media: UCl_6~(2-)and an Unprecedented U(H_2O)_4Cl_4 Structural Unit

摘要

An understanding of actinide-ligand interactions and the identity of the complexes that exist in solution or the solid state is fundamentally important to predicting the overall chemical behaviour of the actinides under scenarios relevant to environmental contamination, separations processes, and nuclear waste management.1 With respect to the latter, actinide-halide complexes have received considerable attention due to their importance in technological processes, specifically under high halide concentrations. Such species have also been examined as a means of understanding covalency in the f-block and as precursors for nonaqueous transuranic chemistry.2~4 In this work, we examined the speciation of uranium halide complexes formed in the presence and absence of various hydrogen-bond donors as a means of assessing the impact of secondary coordination sphere interactions on speciation. Two U(IV) complexes including UCl_6~(2-) and U(H_2O)4C14 were isolated from acidic aqueous solutions and are reported.