Theoretical insights into selective separation of trivalent actinide and lanthanide by ester and amide ligands based on phenanthroline skeleton
Theoretical insights into selective separation of trivalent actinide and lanthanide by ester and amide ligands based on phenanthroline skeleton
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基于菲咯啉骨架的酯和酰胺配体选择性分离三价锕系元素和镧系元素的理论见解
DOI：
10.1039/d0dt00218f
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发表时间：
2020
影响因子：
4
通讯作者：
Shi Wei-Qun
中科院分区：
文献类型：
--
作者：
Wang Cui;Wu Qun-Yan;Wang Cong-Zhi;Lan Jian-Hui;Nie Chang-Ming;Chai Zhi-Fang;Shi Wei-Qun
基于菲咯啉的配体已显示出将三价锕系元素与镧系元素分开的潜在性能。在这项工作中，我们探索了四种基于菲咯啉骨架的酯和酰胺配体，并阐明了Am(III)和Eu(III)离子之间的分离机制。使用标量相对论密度泛函理论对金属-配体配合物的分子几何形状和萃取反应进行建模。结果表明，酰胺基配体比相应的酯基配体与金属离子具有更强的配位能力。根据热力学结果，配体 N,N'-二乙基-N,N'-二甲苯基-2,9-二酰胺-1,10-菲咯啉 (L2) 和 N,N'-(1,10-菲咯啉-2,9-二基)双(N-乙基-P-甲基-N-(对甲苯基)次膦酰胺) (L4) 似乎具有最强的络合能力，这得到了支持 由静电势 (ESP) 和 M–OL 键序的结果得出。此外，配体L2在四种配体中对Am(III)/Eu(III)具有优异的选择性。此外，金属离子与配体之间的键合特性表明，Am(III)/Eu(III)选择性源于具有更多共价特征的Am-N键，配体硬度和键级的分析也支持了这一点。这项工作为了解带有酯基和酰胺基团的菲咯啉衍生配体的 Am(III)/Eu(III) 选择性提供了有用的信息。
Phenanthroline based ligands have shown potential performance for partitioning trivalent actinides from lanthanides. In this work, we have explored four ester and amide ligands based on the phenanthroline skeleton and elucidated the separation mechanism between Am(III) and Eu(III) ions. The molecular geometries and extraction reactions of the metal–ligand complexes were modeled by using scalar-relativistic density functional theory. The results show that the amide based ligands have stronger coordination ability with the metal ions than the corresponding ester based ligands. According to the thermodynamic results, ligands N,N′-diethyl-N,N′-ditolyl-2,9-diamide-1,10-phenanthroline (L2) and N,N′-(1,10-phenanthroline-2,9-diyl)bis(N-ethyl-P-methyl-N-(p-tolyl)phosphinic amide) (L4) appear to have the strongest complexing ability, which is supported by the result of electrostatic potential (ESP) and the M–OL bond orders. Moreover, ligand L2 has excellent selectivity for Am(III)/Eu(III) among the four ligands. Additionally, the bonding properties between the metal ions and the ligands reveal that the Am(III)/Eu(III) selectivity stems from the Am–N bonds with more covalent character, which is supported by the analysis of the hardness of the ligands and the bond orders. This work provides useful information for understanding the Am(III)/Eu(III) selectivity of phenanthroline derived ligands bearing ester and amide groups.