Exploring competitive metal binding and crystallization of UO22+ and Cu2+ tetrahydrofuran-2,3,4,5-tetracarboxylic acid complexes
| Autor: | Tori Z. Forbes, James M. Williams, Allison A. Peroutka, Mikaela M. Pyrch, Maurice K. Payne |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
010405 organic chemistry
Ligand Isothermal titration calorimetry 010402 general chemistry 01 natural sciences 0104 chemical sciences law.invention Inorganic Chemistry Metal chemistry.chemical_compound Crystallography symbols.namesake chemistry law visual_art Materials Chemistry visual_art.visual_art_medium symbols Mother liquor Physical and Theoretical Chemistry Crystallization Raman spectroscopy Single crystal Tetrahydrofuran |
| Zdroj: | Polyhedron. 194:114904 |
| ISSN: | 0277-5387 |
| DOI: | 10.1016/j.poly.2020.114904 |
| Popis: | Solvent extractions are used to separate actinide elements from fission products in nuclear waste streams and the successful isolation of specific species utilize subtle differences in metal ligand binding. Metal ligand binding is also important in crystallization of metal organic materials and herein we explore the importance of competitive binding in the tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THFTCA) system. This ligand has been previously evaluated for the selective extraction of uranium from other lanthanides and actinides and in the current study, we evaluate the crystallization of uranyl-THFTCA complexes in the presence of Cu2+, Sr2+, Th4+, and Ce3+. Three major phases were formed in the crystallization experiments and characterized with single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, and Raman spectroscopy. Two of the resulting phases were novel (UTHF1 ((C4H10N2)[UO2(C8H8O9)2]∙2H2O) and UTHF2 (Na[(UO2)(C8H5O9)(H2O)]∙ 3.5 H2O)), whereas the third (CuTHF1) was previously reported in the literature. Raman spectroscopy was utilized to evaluate spectral changes in the mother liquor of UTHF1, UTHF2, and CuTHF1 over time to assess the crystallization process. Further, isothermal titration calorimetry was used to determine the binding constants for UO22+ and Cu2+ to the THFTCA ligand in solution and evaluate the role of competitive metal binding in this system. The thermodynamic parameters and the crystallographic data were used to justify the formation of a weaker UO22+-THFTCA complex. Formation of a weaker UO22+-THFTCA complex supports our findings that UTHF1 only forms in homomeric systems, but suggests that the crystallization of UTHF2 and CuTHF1 is reliant on the presence of additional counter ions and ligands to change the amount of available THFTCA ligand. |
| Databáze: | OpenAIRE |
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