Solvent Phase Optimizations Improve Correlations with Experimental Stability Constants for Aqueous Lanthanide Complexes. Issue 2 (23rd February 2023)

• Record Type: Journal Article
• Authors: García Alejo, Andrés; De Silva, Nuwan; Liu, Yichen; Windus, Theresa L.; Pérez García, Marilú
• Is Part Of: Solvent extraction and ion exchange. Volume 41:Issue 2(2023)
• Page Start: 241
• Page End: 251
• Publication Date: 2023-02-23
• Subjects: Solvent extraction -- modeling and simulation -- thermodynamics -- extractants -- complexants; Solvent extraction -- Periodicals; Ion exchange -- Periodicals; 660.284248
• DOI: 10.1080/07366299.2022.2160646
• Languages: English
• ISSNs: 0736-6299

Abstract

ABSTRACT: Stability constants provide insight into ion complexation in water. While computational studies have been shown to model the energy of the complexation successfully using a thermodynamic cycle approach, it does not extend to calculating the stability constants for 1:1 lanthanide to ligand complexes in solution. Using B3LYP and 6-31+G* Pople basis with small core effective core potential (ECP) on the lanthanum ion, and a solvent model based on the full solute electron density (SMD) solvation model we computed and compared with previously published stability constants of the ligands: acetate, acetohydroximate, acetylacetonate, methanoate, tropolonate, hydroxide, catecholate, malonate, oxalate, phthalate, and sulfate. The best R 2 values for the thermodynamic cycle can only be determined by separating the mono and divalent ions to achieve an R 2 value of 0.86 and 0.74 for mono and divalent ions, respectively. We show that by optimizing the lanthanide-ligand structures in implicit solvent, we achieve an improved correlation between experimental and computed stability constants of R 2 value of 0.89 for the combined mono and divalent ions.