Theoretical Exploration of Transplutonium Element Separation by Phosphine Oxide-Functionalized Ligands with Different...

Area of Science:

• Nuclear Chemistry
• Materials Science
• Computational Chemistry

Background:

• Transplutonium elements are vital for industry and research.
• Efficient separation of heavy actinides is crucial for their utilization.
• Developing novel separation extractants requires understanding ligand and complex properties.

Purpose of the Study:

• Investigate the extraction and separation capabilities of three phosphine oxide ligands (Ph2PyPO, Ph2BipyPO, Ph2BPPhen) for transplutonium cations (Am3+-Cf3+).
• Analyze the electronic properties of ligands to determine their affinity for transplutonium elements.
• Elucidate the bonding characteristics and extraction mechanisms to guide the design of new extractants.

Main Methods:

• Quasi-relativistic density functional theory (DFT) calculations.
• Analysis of electronic properties, Mayer bonding order, and quantum theory of atoms in molecules (QTAIM).
• Energy decomposition analysis (EDA) of actinide-ligand interactions.

Main Results:

• Ph2BPPhen exhibited enhanced affinity for transplutonium elements compared to other ligands.
• The strength of actinide-oxygen (An-O) bonds increased progressively from Americium (Am) to Californium (Cf).
• Covalent interactions between An(III) and ligands strengthened across the Am-Cf series, with Ph2BPPhen showing superior separation effects.

Conclusions:

• Ligand backbone modifications significantly influence bonding and extraction efficiency for transplutonium elements.
• Ph2BPPhen is a promising candidate for developing advanced separation extractants.
• This study provides fundamental insights for designing effective ligands for heavy actinide separation.