{"title":"Theoretical Study on Coordination Chemistry of Two Water-Soluble Ligands for Stripping Separation of Transplutonium Ions.","authors":"Pin-Wen Huang, Peng Ren, Ming Qi","doi":"10.1002/asia.202500835","DOIUrl":null,"url":null,"abstract":"<p><p>Purification and mutual separation of trivalent actinides (An<sup>3</sup>⁺: Am, Cm, Bk, Cf) present significant challenges in nuclear waste treatment. Elucidating complexation mechanisms with stripping ligands is crucial for ligand development. Given the radiotoxicity, quantum chemical methods are essential. This DFT study investigates chelation of An<sup>3</sup>⁺ ions with water-soluble ligands H<sub>2</sub>L<sup>2</sup>ᵖʸ and H<sub>2</sub>L<sup>2</sup>ᵖᶻ. Probable back-extraction complexes ([AnL<sup>i</sup>(H<sub>2</sub>O)ⱼ]⁺, AnL<sup>i</sup>(NO<sub>3</sub>)(H<sub>2</sub>O)<sup>k</sup>) exhibit near-identical geometries with minor An─O/N bond length variations. Analyses reveal enhanced chelating ability for diamine N atoms adjacent to carboxylate O versus N-heterocyclic donors (pyridine/pyrazine). Crucially, interaction intensity and partial covalency between An<sup>3</sup>⁺ and donor atoms (N<sub>AM</sub>, O<sub>CA</sub>, N<sub>PY/PZ</sub>) display a distinct bimodal variation with Cm as the turning point. This trend likely originates from closer orbital energy matching between the 5f orbitals of Am/Bk/Cf and ligand 2p orbitals compared to Cm. Thermodynamic analyses demonstrate superior back-extraction ability for H<sub>2</sub>L<sup>2</sup>ᵖʸ, while H<sub>2</sub>L<sup>2</sup>ᵖᶻ excels in Am/Eu separation. The downward-upward trend in reaction free energies aligns with covalency variations, suggesting potential intra-group separation capability for all four ions. Estimated separation factors SF<sub>Am/Cm</sub>, SF<sub>Bk/Cm</sub>, and SF<sub>Cf/Cm</sub> are projected within 2.45-3.45.</p>","PeriodicalId":145,"journal":{"name":"Chemistry - An Asian Journal","volume":" ","pages":"e00835"},"PeriodicalIF":3.3000,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemistry - An Asian Journal","FirstCategoryId":"1","ListUrlMain":"https://doi.org/10.1002/asia.202500835","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Purification and mutual separation of trivalent actinides (An3⁺: Am, Cm, Bk, Cf) present significant challenges in nuclear waste treatment. Elucidating complexation mechanisms with stripping ligands is crucial for ligand development. Given the radiotoxicity, quantum chemical methods are essential. This DFT study investigates chelation of An3⁺ ions with water-soluble ligands H2L2ᵖʸ and H2L2ᵖᶻ. Probable back-extraction complexes ([AnLi(H2O)ⱼ]⁺, AnLi(NO3)(H2O)k) exhibit near-identical geometries with minor An─O/N bond length variations. Analyses reveal enhanced chelating ability for diamine N atoms adjacent to carboxylate O versus N-heterocyclic donors (pyridine/pyrazine). Crucially, interaction intensity and partial covalency between An3⁺ and donor atoms (NAM, OCA, NPY/PZ) display a distinct bimodal variation with Cm as the turning point. This trend likely originates from closer orbital energy matching between the 5f orbitals of Am/Bk/Cf and ligand 2p orbitals compared to Cm. Thermodynamic analyses demonstrate superior back-extraction ability for H2L2ᵖʸ, while H2L2ᵖᶻ excels in Am/Eu separation. The downward-upward trend in reaction free energies aligns with covalency variations, suggesting potential intra-group separation capability for all four ions. Estimated separation factors SFAm/Cm, SFBk/Cm, and SFCf/Cm are projected within 2.45-3.45.
期刊介绍:
Chemistry—An Asian Journal is an international high-impact journal for chemistry in its broadest sense. The journal covers all aspects of chemistry from biochemistry through organic and inorganic chemistry to physical chemistry, including interdisciplinary topics.
Chemistry—An Asian Journal publishes Full Papers, Communications, and Focus Reviews.
A professional editorial team headed by Dr. Theresa Kueckmann and an Editorial Board (headed by Professor Susumu Kitagawa) ensure the highest quality of the peer-review process, the contents and the production of the journal.
Chemistry—An Asian Journal is published on behalf of the Asian Chemical Editorial Society (ACES), an association of numerous Asian chemical societies, and supported by the Gesellschaft Deutscher Chemiker (GDCh, German Chemical Society), ChemPubSoc Europe, and the Federation of Asian Chemical Societies (FACS).