"Straining" to Separate the Rare Earths: How the Lanthanide Contraction Impacts Chelation by Diglycolamide Ligands.
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.
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Ross J
http://orcid.org/0000-0001-7691-5205
RJ
Ellis
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Derek M
DM
Brigham
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Laetitia
L
Delmau
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Alexander S
AS
Ivanov
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.|Department of Chemistry, The University of Tennessee , Buehler Hall 1420 Circle Drive, Knoxville, Tennessee 37996-1600, United States.
Neil J
NJ
Williams
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.|Department of Chemical & Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh , 804 Benedum Hall, 3700 O'Hara Street, Pittsburgh, Pennsylvania 15261, United States.
Minh Nguyen
MN
Vo
Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States.
Benjamin
B
Reinhart
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Bruce A
BA
Moyer
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Vyacheslav S
http://orcid.org/0000-0002-6501-6594
VS
Bryantsev