Abstract
Metal ion hydrolysis and condensation reactions are critical to describing the chemical behavior of the tetravalent actinides (An) due to their high charge density. This recognition has fueled synthetic efforts targeting polynuclear actinide–oxo clusters. Oligomers ranging from trimers to octatriacontamers have been reported, with the hexameric unit, which typically exhibits a [An6(OH)4O4]12+ core, representing the most pervasive cluster. Hexamers decorated by a range of ligands, including carboxylates, sulfates, and chlorides, have been described. Previous reports have demonstrated the formation of hexamers for Th, U, Np, and Pu both in solution and the solid state, yet little work has focused on the synthesis and properties of structurally analogous clusters across the early An series using the same complexing ligand. Here, a series of benzoate (Bz) decorated actinide–oxo/hydroxo hexamers of the same general formula [An6O4(OH)4(Bz)12(H2O)n], where An = Th, U, Np, Pu and n = 6 for Th and 4 for U–Pu is reported. The title compounds were characterized by X-ray diffraction, UV-vis–NIR absorbance, Raman, and infrared spectroscopy. Notably isolation of these phases and elucidation of the parameters that underpin their formation provides insight into the ways differences in metal ion charge density manifest across the early tetravalent actinides, both in their synthetic and structural chemistry.
| Original language | English |
|---|---|
| Pages (from-to) | 507-515 |
| Number of pages | 9 |
| Journal | CrystEngComm |
| Volume | 27 |
| Issue number | 4 |
| DOIs | |
| State | Published - Dec 13 2024 |
| Externally published | Yes |
Funding
Synthesis and characterization of the thorium and uranium compounds were performed at Georgetown University, under the support of the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Early Career Research Program under Award DE-SC0019190. Both TLM and KEK were supported by this award. The neptunium and plutonium work was conducted at Pacific Northwest National Laboratory by TLM, RGS, and AA. TLM was supported under award DE-SC0019190. The funding mechanism for work performed by TLM and AA at PNNL was the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory, a multiprogram national laboratory operated by Battelle for the Department of Energy. AA is grateful for support from the Linus Pauling Distinguished Postdoctoral Fellowship. RGS was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, Heavy Element Chemistry program, under Award FWP 73200. The authors thank Ashley Hastings for providing insight into synthetic techniques which led to the successful isolation of the Th compound and Lulio Sanz for assistance in collecting solid-state UV-vis absorption data of U . 6 Synthesis and characterization of the thorium and uranium compounds were performed at Georgetown University, under the support of the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Early Career Research Program under Award DE-SC0019190. Both TLM and KEK were supported by this award. The neptunium and plutonium work was conducted at Pacific Northwest National Laboratory by TLM, RGS, and AA. TLM was supported under award DESC0019190. The funding mechanism for work performed by TLM and AA at PNNL was the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory, a multiprogram national laboratory operated by Battelle for the Department of Energy. AA is grateful for support from the Linus Pauling Distinguished Postdoctoral Fellowship. RGS was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, Heavy Element Chemistry program, under Award FWP 73200. The authors thank Ashley Hastings for providing insight into synthetic techniques which led to the successful isolation of the Th compound and Lulio Sanz for assistance in collecting solid-state UV-vis absorption data of U6.