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Ansari SA, Bhattacharyya A, Mohapatra PK, Verma PK, Urkude RR, Egberink RJM, Verboom W. Understanding the Complexation of Alkyl-Substituted Nitrilotriacetamides with Uranium: A Study by Absorption Spectroscopy and Microcalorimetry. Inorg Chem 2024; 63:11270-11278. [PMID: 38842429 DOI: 10.1021/acs.inorgchem.4c01123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Complexation thermodynamics of UO22+ ions with a series of alkyl-substituted nitrilotriacetamides (NTA) was investigated by absorption spectroscopy and microcalorimetry. The hexamethyl derivative of NTA (HMNTA) forms the weakest two successive complexes with UO22+ ions with stability constants of log β11 = 3.5 ± 0.1 and log β12 = 6.1 ± 0.1. The formation constant values increased linearly with increasing alkyl chain length of the substituents from hexamethyl NTA to hexabutyl NTA (HBNTA) and to hexahexyl NTA (HHNTA). The complexation with each ligand was both enthalpy and entropy driven with exothermic enthalpy changes of ΔH11 = -14.7 ± 1.0 kJ/mol, ΔH12 = -10.2 ± 0.8 kJ/mol for HMNTA, ΔH11 = -19.2 ± 1.2 kJ/mol, ΔH12 = -16.4 ± 1.1 kJ/mol for HBNTA, and ΔH11 = -21.3 ± 1.4 kJ/mol, ΔH12 = -19.4 ± 2.3 kJ/mol for HHNTA. Similarly, the positive entropy changes with each ligand were ΔS11 = 18.1 ± 2.7 J/mol/K, ΔS12 = 82.9 ± 3.8 J/mol/K for HMNTA, ΔS11 = 14.4 ± 1.2 J/mol/K, ΔS12 = 87.2 ± 4.2 J/mol/K for HBNTA, and ΔS11 = 16.1 ± 2.4 J/mol/K, ΔS12 = 92.6 ± 3.1 J/mol/K for HHNTA. Structural features of the complex suggest the participation of two ligands coordinating in a bidentate mode via the carbonyl oxygens. The [UO2L2]2+ complexes appear to be noncentrosymmetric with two ligands and one water molecule occupying the equatorial plane of the dioxo uranyl cation. The structure of the complex was confirmed by 1H NMR titration, EXAFS measurements, and DFT calculations.
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Affiliation(s)
- Seraj A Ansari
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | | | | | - Parveen K Verma
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Rajashri R Urkude
- Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Richard J M Egberink
- Laboratory of Molecular Nanofabrication, Department of Molecules & Materials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Willem Verboom
- Laboratory of Molecular Nanofabrication, Department of Molecules & Materials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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Wu S, Li AY. Theoretical investigations into the bonding and separation properties of non-rigid, partially rigid, and rigid ligands derived from Et-Tol-PTA with trivalent lanthanides and actinides. Phys Chem Chem Phys 2024; 26:2205-2217. [PMID: 38164958 DOI: 10.1039/d3cp04717b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The separation of trivalent actinide elements from lanthanide elements represents one of the most formidable challenges within the context of nuclear waste partitioning and transmutation (P&T) processes. Consequently, we embarked on a systematic investigation aimed at elucidating the bonding properties and thermodynamic behavior of a N-ethyl-N-tolyl-2-amide-1,10-phenanthroline (Et-Tol-PTA) ligand in conjunction with trivalent actinide and lanthanide elements. This investigation involved the utilization of various density functional theory (DFT) methods and a comparative analysis between small-core pseudopotential basis sets and all-electron basis sets. It was found that well-performing results were achieved using the PBE0 functional in both bond length and thermodynamic energy calculations, with minimal impact being exerted by the basis set on the results. Furthermore, an exploration was carried out into the bonding and thermodynamic properties of trivalent actinides and lanthanides with ligands derived from Et-Tol-PTA, encompassing non-rigid (La), partially rigid (Lb, Lc), and rigid (Ld) ligands. Thermodynamically, advantages in the separation of Am(III)/Eu(III) were exhibited by Lb and Lc ligands, while excellent performance in the separation of Am(III)/Cm(III) was demonstrated by the La ligand. Analyses conducted using quantum theory of atoms in molecules (QTAIM), reduced density gradient (RDG), and natural bond orbital (NBO) methodologies revealed the presence of partial covalent character in the bonds between oxygen (O) and metal (M), as well as between nitrogen (N) and metal (M), with a higher degree of covalent character being observed in O-Am and N-Am bonds compared to O-Cm/Eu and N-Cm/Eu interactions.
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Affiliation(s)
- Shouqiang Wu
- School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
| | - An Yong Li
- School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
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Liu Y, Kang Y, Bao M, Cao H, Weng C, Dong X, Hao H, Tang X, Chen J, Wang L, Xu C. Hydroxyl-group functionalized phenanthroline diimides as efficient masking agents for Am(III)/Eu(III) separation under harsh conditions. JOURNAL OF HAZARDOUS MATERIALS 2024; 462:132756. [PMID: 37866146 DOI: 10.1016/j.jhazmat.2023.132756] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 10/24/2023]
Abstract
The separation of Lns(III) from radioactive Ans(III) in high-level liquid waste remains a formidable hydrometallurgical challenge. Water-soluble ligands are believed to be new frontiers in the search of efficient Lns/Ans separation ligands to close the nuclear fuel cycles and dealing with current existing nuclear waste. Currently, the development of hydrophilic ligands far lags behind their lipophilic counterparts due to their complicated synthetic procedures, inferior extraction performances, and acid tolerances. In this paper, we have showed a series of hydroxyl-group functionalized phenanthroline diimides were efficient masking agents for Am(III)/Eu(III) separation under high acidity (˃ 1 M HNO3). Record high SFEu(III)/Am(III) of 162 and 264 were observed for Phen-2DIC2OH and Phen-2DIC4OH in 1.25 M HNO3 which represents the best Eu(III)/Am(III) separation performance at this acidity. UV-vis absorption, NMR and TRLFS titrations were conducted to elucidate the predominant of 1:1 ligand/metal species under extraction conditions. X-ray data of both the ligand and Eu(III) complex together with DFT calculations revealed the superior extraction performances and selectivities. The current reported hydrophilic ligands were easy to prepare and readily to scale-up, acid tolerant and highly efficient, together with their CHON-compatible nature make them promising candidates in the development of advanced separation processes.
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Affiliation(s)
- Yaoyang Liu
- Institute of Nuclear and New Energy Technology, Tsinghua University, Haidian District, Beijing 100084, China
| | - Yu Kang
- Department of Chemistry, Capital Normal University, Haidian District, Beijing 100048, China
| | - Mingjie Bao
- Department of Chemistry, Capital Normal University, Haidian District, Beijing 100048, China
| | - Hong Cao
- Institute of Nuclear and New Energy Technology, Tsinghua University, Haidian District, Beijing 100084, China
| | - Chaoqun Weng
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 China
| | - Xue Dong
- Institute of Nuclear and New Energy Technology, Tsinghua University, Haidian District, Beijing 100084, China
| | - Huaixin Hao
- Institute of Nuclear and New Energy Technology, Tsinghua University, Haidian District, Beijing 100084, China
| | - Xiaoyan Tang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 China
| | - Jing Chen
- Institute of Nuclear and New Energy Technology, Tsinghua University, Haidian District, Beijing 100084, China.
| | - Li Wang
- Department of Chemistry, Capital Normal University, Haidian District, Beijing 100048, China.
| | - Chao Xu
- Institute of Nuclear and New Energy Technology, Tsinghua University, Haidian District, Beijing 100084, China.
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