%0 Journal Article %A Baldwin, Anna G. %A Ivanov, Alexander S. %A Williams, Neil J. %A Ellis, Ross J. %A Moyer, Bruce A. %A Bryantsev, Vyacheslav S. %A Shafer, Jenifer C. %D 2018 %T Outer-Sphere Water Clusters Tune the Lanthanide Selectivity of Diglycolamides %U https://acs.figshare.com/articles/journal_contribution/Outer-Sphere_Water_Clusters_Tune_the_Lanthanide_Selectivity_of_Diglycolamides/6515942 %R 10.1021/acscentsci.8b00223.s001 %2 https://acs.figshare.com/ndownloader/files/11984150 %K distribution studies %K metal ions %K Lanthanide Selectivity %K inner-sphere interactions %K Outer-Sphere Water Clusters Tune %K selectivity %K extractant N %K outer-sphere interactions %K TODGA %K Complementary investigations %K importance %K fuel reprocessing %K separation systems %K outer-sphere nitrate ions %K water clusters %K biphasic extraction %K rare-earth refining technologies %K nonpolar environment %K lanthanide extraction %K coextracted water %K Current investigations %K block metal ions %K hydrogen-bonding interactions %K energy systems %K outer-sphere region %K chelating agents %K donor groups %K dynamics simulations %X Fundamental understanding of the selective recognition and separation of f-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 N,N,N′,N′-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. %I ACS Publications