2024-08-27 サンディア国立研究所(SNL)
＜関連情報＞
- https://newsreleases.sandia.gov/metal_separation/
- https://pubs.acs.org/doi/10.1021/acsami.4c09445
- https://pubs.rsc.org/en/content/articlelanding/2024/cp/d4cp00880d
- https://pubs.rsc.org/en/content/articlelanding/2024/cc/d4cc00320a
Cr-およびZr-ベース有機金属骨格に吸着したランタノイドの局所配位環境 Local Coordination Environment of Lanthanides Adsorbed onto Cr- and Zr-based Metal–Organic Frameworks
Anastasia G. Ilgen,R. Eric Sikma,Dorina F. Sava Gallis,Kevin Leung,Chengjun Sun,Boyoung Song,Kadie M. M. Sanchez,Jacob G. Smith
ACS Applied Materials & Interfaces Published: August 26, 2024
DOI:https://doi.org/10.1021/acsami.4c09445
Abstract
Separating individual lanthanide (Ln) elements in aqueous mixtures is challenging. Ion-selective capture by porous materials, such as metal–organic frameworks (MOFs), is a promising approach. To design ion-selective MOFs, molecular details of the Ln adsorption complexes within the MOFs must be understood. We determine the local coordination environment of lanthanides Nd(III), Gd(III), and Lu(III) adsorbed onto Cr(III)-based terephthalate MOF (Cr-MIL-101) and Zr(IV)-based Universitet in Oslo MOFs (UiO-66 and UiO-68) and their derivatives. In the Cr(III)- and Zr(IV)-based MOFs, Ln adsorb as inner-sphere complexes at the metal oxo clusters, regardless of whether the organic linkers are decorated with amino groups. Missing linkers result in favorable Ln binding sites at oxo clusters; however, Ln can coordinate to metal sites even with linkers in place. MOF functionalization with phosphonate groups led to Ln chemisorption onto these groups, which out-compete metal cluster sites. Ln form monodentate and bidentate and mononuclear and binuclear surface complexes. We conclude that MOFs for ion-selective Ln capture can be designed by a combination of (1) maximizing metal-lanthanide interactions via shared O atoms at the metal oxo cluster sites, where mixed oxo clusters can lead to ion-selective Ln adsorption, and (2) functionalizing MOFs with Ln-selective groups capable of out-completing the metal oxo cluster sites.
不均一配位子結合を介したランタニドの分離のモデリング Modeling separation of lanthanides via heterogeneous ligand binding
Kevin Leung and Anastasia G. Ilgen
Physical Chemistry Chemical Physics Published:09 Jul 2024
DOI:https://doi.org/10.1039/D4CP00880D
Abstract
Individual lanthanide elements have physical/electronic/magnetic properties that make each useful for specific applications. Several of the lanthanides cations (Ln3+) naturally occur together in the same ores. They are notoriously difficult to separate from each other due to their chemical similarity. Predicting the Ln3+ differential binding energies (ΔΔE) or free energies (ΔΔG) at different binding sites, which are key figures of merit for separation applications, will help design of materials with lanthanide selectivity. We apply ab initio molecular dynamics (AIMD) simulations and density functional theory (DFT) to calculate ΔΔG for Ln3+ coordinated to ligands in water and embedded in metal–organic frameworks (MOFs), and ΔΔE for Ln3+ bonded to functionalized silica surfaces, thus circumventing the need for the computational costly absolute binding (free) energies ΔG and ΔE. Perturbative AIMD simulations of water-inundated simulation cells are applied to examine the selectivity of ligands towards adjacent Ln3+ in the periodic table. Static DFT calculations with a full Ln3+ first coordination shell, while less rigorous, show that all ligands examined with net negative charges are more selective towards the heavier lanthanides than a charge-neutral coordination shell made up of water molecules. Amine groups are predicted to be poor ligands for lanthanide-binding. We also address cooperative ion binding, i.e., using different ligands in concert to enhance lanthanide selectivity.
Zr-MOFの細孔化学のチューニングによる錯体流からの効率的な金属イオン捕捉 Tuning the pore chemistry of Zr-MOFs for efficient metal ion capture from complex streams
R. Eric Sikma,Boyoung Song,Jacob I. Deneff,Jacob Smith,Kadie Sanchez,Raphael A. Reyes,Luke M. Lucero,Keith J. Fritzsching,Anastasia G. Ilgen and Dorina F. Sava Gallis
Chemical omminications Published:29 Apr 2024
DOI:https://doi.org/10.1039/D4CC00320A
Abstract
Metal–organic frameworks (MOFs) have shown promise for adsorptive separations of metal ions. Herein, MOFs based on highly stable Zr(IV) building units were systematically functionalized with targeted metal binding groups. Through competitive adsorption studies, it was shown that the selectivity for different metal ions was directly tunable through functional group chemistry.
