Outer-Sphere Water Clusters Tune the Lanthanide Selectivity
of Diglycolamides
Anna G. Baldwin
Alexander S. Ivanov
Neil J. Williams
Ross J. Ellis
Bruce A. Moyer
Vyacheslav S. Bryantsev
Jenifer C. Shafer
10.1021/acscentsci.8b00223.s001
https://acs.figshare.com/articles/journal_contribution/Outer-Sphere_Water_Clusters_Tune_the_Lanthanide_Selectivity_of_Diglycolamides/6515942
Fundamental
understanding of the selective recognition and separation of <i>f</i>-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 <i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-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.
2018-06-13 21:29:28
distribution studies
metal ions
Lanthanide Selectivity
inner-sphere interactions
Outer-Sphere Water Clusters Tune
selectivity
extractant N
outer-sphere interactions
TODGA
Complementary investigations
importance
fuel reprocessing
separation systems
outer-sphere nitrate ions
water clusters
biphasic extraction
rare-earth refining technologies
nonpolar environment
lanthanide extraction
coextracted water
Current investigations
block metal ions
hydrogen-bonding interactions
energy systems
outer-sphere region
chelating agents
donor groups
dynamics simulations