“Straining” to Separate the Rare Earths: How the Lanthanide Contraction Impacts Chelation by Diglycolamide Ligands

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• 作者：Ross J. EllisDerek M. Brigham ; Laetitia Delmau ; Alexander S. Ivanov ; Neil J. Williams ; Minh Nguyen Vo ; Benjamin Reinhart ; Bruce A. Moyer ; Vyacheslav S. Bryantsev
• 刊名：Inorganic Chemistry
• 出版年：2017
• 出版时间：February 6, 2017
• 年：2017
• 卷：56
• 期：3
• 页码：1152-1160
• 全文大小：479K
• ISSN：1520-510X

文摘

The subtle energetic differences underpinning adjacent lanthanide discrimination are explored with diglycolamide ligands. Our approach converges liquid–liquid extraction experiments with solution-phase X-ray absorption spectroscopy (XAS) and density functional theory (DFT) simulations, spanning the lanthanide series. The homoleptic [(DGA)₃Ln]³⁺ complex was confirmed in the organic extractive solution by XAS, and this was modeled using DFT. An interplay between steric strain and coordination energies apparently gives rise to a nonlinear trend in discriminatory lanthanide ion complexation across the series. Our results highlight the importance of optimizing chelate molecular geometry to account for both coordination interactions and strain energies when designing new ligands for efficient adjacent lanthanide separation for rare-earth refining.