Insights into the Extraction of Actinides from Lanthanides Using 3, 3'‐Dimethoxy‐phenyl‐bis‐1, 2, 4‐triazinyl‐2, 6‐pyridine Ligand – A DFT Study. Issue 44 (24th November 2020)

• Record Type: Journal Article
• Authors: Ebenezer, Cheriyan; Solomon, Rajadurai Vijay
• Is Part Of: ChemistrySelect. Volume 5:Issue 44(2020)
• Page Start: 13895
• Page End: 13901
• Publication Date: 2020-11-24
• Subjects: Actinide extraction -- BTP ligand -- Density functional calculations -- N ligands -- Spent Nuclear Fuel; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202003240
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Recently reported 3, 3'‐dimethoxy‐phenyl‐bis‐1, 2, 4‐triazinyl‐2, 6‐pyridine (DMOP‐ BTP) ligand is recognized as an efficient candidate for the stripping of actinides (An) from lanthanides (Ln) in nuclear wastes in nitric acid medium. However, the complexation behaviour and selectivity of this DMOP‐BTP ligand towards An III /Ln III is still unclear. In order to understand the origin of complexation of this ligand, a series of metal ions (M 3+ =Ce, Nd, Eu, U, Am, Cm) have been chosen and its binding ability to form ML(NO3 )3 (L=DMOP‐ BTP) complex is studied using scalar relativistic ZORA/DFT calculations. Metal ‐Nitrogen bond lengths obtained from optimized geometries reveal that An III prefer binding to DMOP‐BTP ligand compared to Ln III . To elucidate the metal‐ligand bonding nature, Mayer and Nalewajsk‐ Mrozek (NM) bond order analyses have been carried out. Quantum Theory of Atoms In Molecules (QTAIM) and Energy Decomposition Analysis (EDA) have been done using the optimized geometries to comprehend the bonding situation in these ML(NO3 )3 complexes. Results reveal that the bonds of An III ions tend to have a higher covalency compared to that of their lanthanide ions. Furthermore, it is understood that the NO3 ions around the metal ion also take part in interaction with the ligand and help in the stabilization of the metal complex. Thus, this work throws light on the preferential selectivity of the DMOP‐ BTP ligand for An III ions over Ln III ions. Abstract : Relativistic density functional theory calculations have been done to understand the feasibility of using 3, 3'‐dimethoxy‐phenyl‐bis‐1, 2, 4‐triazinyl‐2, 6‐pyridine (DMOP‐BTP) ligand in the partitioning of actinides from lanthanides in the management of nuclear wastes. The origin of selectivity is ascertained through a detailed electronic structure characterization of (M(DMOP‐BTP)(NO3 )3 ) complexes where M 3+ =Ce, Nd, Eu, U, Am & Cm. Results show that DMOP‐BTP prefers trivalent actinides over lanthanides. This work offers insights for designing future ligands with enhanced selectivity.