Journal article
Exploring competitive metal binding and crystallization of UO22+ and Cu2+ tetrahydrofuran-2,3,4,5-tetracarboxylic acid complexes
Polyhedron, Vol.194, 114904
01/15/2021
DOI: 10.1016/j.poly.2020.114904
Abstract
Crystallization of homometallic carboxylic acid metal complexes from heterometallic solutions containing f-elements. The characterization of two new uranyl phases and insights to metal–ligand bind preferences are provided.
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•Crystallization of homometallic products from heterometallic solutions.•Isolation of two new uranyl phases that includes a 1:2 U:THFTCA complex.•Structural confirmation of the tridentate binding mode with the uranyl cation.•Spectral characterization using Raman spectroscopy.•Isothermal calorimetry results of THFTCA binding with UO22+, La3+, Cu2+, and Sr2+
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.
Details
- Title: Subtitle
- Exploring competitive metal binding and crystallization of UO22+ and Cu2+ tetrahydrofuran-2,3,4,5-tetracarboxylic acid complexes
- Creators
- Allison A PeroutkaMikaela M PyrchJames M WilliamsMaurice K PayneTori Z Forbes
- Resource Type
- Journal article
- Publication Details
- Polyhedron, Vol.194, 114904
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.poly.2020.114904
- ISSN
- 0277-5387
- eISSN
- 1873-3719
- Grant note
- DOI: 10.13039/100000015, name: U.S. Department of Energy
- Language
- English
- Date published
- 01/15/2021
- Academic Unit
- Civil and Environmental Engineering; Chemistry; Core Research Facilities
- Record Identifier
- 9984216694602771
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