Selective Extraction of Americium(III) over Europium(III) Ions with Pyridylpyrazole Ligands: Structure-Property Relationships

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• 作者：Dongping Su ; Ying Liu ; Shimeng Li ; Songdong Ding ; Yongdong Jin ; Zhipeng Wang ; Xiaoyang Hu and Lirong Zhang
• 刊名：European Journal of Inorganic Chemistry
• 出版年：2017
• 出版时间：January 18, 2017
• 年：2017
• 卷：2017
• 期：3
• 页码：651-658
• 全文大小：1643K
• ISSN：1099-0682c

文摘

To clarify the structure–property relationships of pyridylpyrazole ligands and provide guidance for the design of new and more efficient ligands for the selective extraction of actinides over lanthanides, a series of alkyl-substituted pyridylpyrazole ligands with different branched chains at different positions of the pyrazole ring were synthesized. Extraction experiments showed that the pyridylpyrazole ligands exhibited good selective extraction abilities for Am^III ions, and the steric effects of the branched chain had a significant impact on the distribution ratios of Am^III and Eu^III ions as well as the separation factor. Moreover, both slope analyses and UV/Vis spectrometry titrations indicated the formation of a 1:1 complex of 2-(1-octyl-1H-pyrazol-3-yl)pyridine (C8-PypzH) with Eu^III ions. The stability constant (log K) for this complex obtained from the UV/Vis titration was 4.45 ± 0.04. Single crystals of the complexes of 3-(2-pyridyl)pyrazole (PypzH) with Eu(NO₃)₃ and Sm(NO₃)₃ were obtained; PypzH acts as a bidentate ligand in the crystal structures, and the N atom with a bound H atom did not participate in the coordination. In general, this study revealed some interesting findings on the effects of the alkyl-chain structure and the special complexation between pyridylpyrazole ligands and Ln^III ions.