1. 'Straining' to Separate the Rare Earths: How the Lanthanide Contraction Impacts Chelation by Diglycolamide Ligands
- Author
-
Benjamin Reinhart, Derek M. Brigham, Minh Nguyen Vo, Neil J. Williams, Lætitia H. Delmau, Bruce A. Moyer, Vyacheslav S. Bryantsev, Alexander S. Ivanov, and Ross J. Ellis
- Subjects
Lanthanide ,Lanthanide contraction ,X-ray absorption spectroscopy ,Absorption spectroscopy ,010405 organic chemistry ,Chemistry ,Inorganic chemistry ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Molecular geometry ,Computational chemistry ,Density functional theory ,Chelation ,Physical and Theoretical Chemistry ,Homoleptic - Abstract
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.
- Published
- 2016