A Computational Approach to Predicting Ligand Selectivity for the Size-Based Separation of Trivalent Lanthanides

Reprocessing of high-level waste is a key step in advancing sustainable energy systems. The development of efficient chelating agents for trivalent f-block metal ions is essential for increasing the efficiency of nuclear-waste remediation and extractive hydrometallurgy of rare-earth elements. Although computer-aided screening could lead to a more rapid discovery of superior ligands, an accurate theoretical description of the solvation effects for trivalent metal ions is currently a stumbling block in qualitative predictions for selectivity trends along the lanthanide series. In this work, we propose a robust model to describe the differential effect of solvation in the competitive binding of a ligand with lanthanides by including weakly coordinated counterions in the complexes of more than a +1 charge. The success of this approach in quantitatively reproducing aqueous selectivities demonstrates its potential for the design and screening of new ligands for efficient size-based separation.