Outer-Sphere Water Clusters Tune the Lanthanide Selectivity of Diglycolamides
Outer-Sphere Water Clusters Tune the Lanthanide Selectivity of Diglycolamides
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DOI：
10.1021/acscentsci.8b00223
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发表时间：
2018-06-27
影响因子：
18.2
通讯作者：
Shafer, Jenifer C.
中科院分区：
文献类型：
--
作者：
Baldwin, Anna G.;Ivanov, Alexander S.;Shafer, Jenifer C.
对螯合剂选择性识别和分离f区金属离子的基本理解对于推进可持续能源系统至关重要。目前这方面的研究主要集中在金属离子与配体给体基团之间的内球相互作用的研究，而在很大程度上忽略了外球区域的分子相互作用对选择性的影响。本文探讨了溶剂化萃取剂N，N，N '，N'-四辛基二甘醇酰胺（TODGA）在液-液萃取体系中对相邻镧系元素选择性的根本原因，这与核燃料后处理和稀土精炼技术有关。补充调查整合分布研究，量子力学计算和经典的分子动力学模拟建立一个共提取水和镧系元素提取TODGA整个系列之间的关系，指出在非极性环境中的外层硝酸根离子和水簇之间的氢键相互作用的重要性。我们的研究结果具有重要意义的设计新的有效的分离系统和过程，强调调整内外球相互作用的重要性，以获得总的控制选择性的双相萃取镧系元素。
Fundamental understanding of the selective recognition and separation of f-block metal ions by chelating agents is of crucial importance for advancing sustainable energy systems. Current investigations in this area are mostly focused on the study of inner-sphere interactions between metal ions and donor groups of ligands, while the effects on the selectivity resulting from molecular interactions in the outer-sphere region have been largely overlooked. Herein, we explore the fundamental origins of the selectivity of the solvating extractant N,N,N',N'-tetraoctyl diglycolamide (TODGA) for adjacent lanthanides in a liquid-liquid extraction system, which is of relevance to nuclear fuel reprocessing and rare-earth refining technologies. Complementary investigations integrating distribution studies, quantum mechanical calculations, and classical molecular dynamics simulations establish a relationship between coextracted water and lanthanide extraction by TODGA across the series, pointing to the importance of the hydrogen-bonding interactions between outer-sphere nitrate ions and water clusters in a nonpolar environment. Our findings have significant implications for the design of novel efficient separation systems and processes, emphasizing the importance of tuning both inner-and outer-sphere interactions to obtain total control over selectivity in the biphasic extraction of lanthanides.