Miao Yujie, Xu Lei, Yang Xiao, Wang Shihui, Zhang Jian, Xu Chao, Xiao Chengliang
College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, Zhejiang University, Hangzhou 310058, China.
Inorg Chem. 2022 Nov 7;61(44):17911-17923. doi: 10.1021/acs.inorgchem.2c03346. Epub 2022 Oct 25.
Two novel asymmetric hard-soft combined ligands, diphenyl(6-(5,9,9-trimethyl-5,6,7,8-tetrahydro-5,8-methanobenzo-[1,2,4]triazin-3-yl)pyridin-2-yl)phosphine oxide (Ph-MTP) and butylphenyl(6-(5,9,9-trimethyl-5,6,7,8-tetrahydro-5,8-methanobenzo-[1,2,4]triazin-3-yl)pyridin-2-yl)phosphine oxide (BuPh-MTP), were designed based on the combination of the nature of phosphoryl and triazinyl groups for the selective extraction of trivalent minor actinides from lanthanides. The synthesis of these two ligands and their solvent extraction and complexation behaviors with Am(III) and typical lanthanides were investigated using UV-vis and time-resolved fluorescence spectrophotometry, H/P NMR spectrometry, single-crystal X-ray diffraction, and DFT calculation methods. Solvent extraction experiments showed that both the ligands had strong extraction ability and high selectivity toward Am(III) over Eu(III) from the highly acidic HNO solution. The separation factors () of these two ligands ranged from 17 to 26, with the concentrations of HNO increasing from 1.0 to 4.0 M. Slope analysis showed that the 3:1 ligand/metal complex was the prevailing species formed during extraction. The formation of the 3:1 ratio of the species of these two ligands with lanthanides was also identified by UV-vis spectrophotometry and single crystallography methods. The stability constants for the formation of the 1:3 complexes of Ph-MTP and BuPh-MTP with Nd(III) were determined as 7.06 ± 0.015 and 6.67 ± 0.007, respectively. The geometric structures of the 1:3 complexes were clearly illustrated using the single-crystal X-ray diffraction technique and DFT theoretical calculation. This work provides an effective strategy to design new asymmetric hard-soft mixed actinide extractants by combining two different functional groups in one ligand, and the interaction mechanism between the functional groups and metal ions needs to be further investigated.
基于磷酰基和三嗪基的性质组合，设计了两种新型不对称硬-软组合配体，二苯基(6-(5,9,9-三甲基-5,6,7,8-四氢-5,8-亚甲基苯并-[1,2,4]三嗪-3-基)吡啶-2-基)氧化膦(Ph-MTP)和丁基苯基(6-(5,9,9-三甲基-5,6,7,8-四氢-5,8-亚甲基苯并-[1,2,4]三嗪-3-基)吡啶-2-基)氧化膦(BuPh-MTP)，用于从镧系元素中选择性萃取三价次锕系元素。采用紫外可见光谱和时间分辨荧光光谱法、H/P NMR光谱法、单晶X射线衍射法和DFT计算方法研究了这两种配体的合成及其与Am(III)和典型镧系元素的溶剂萃取和络合行为。溶剂萃取实验表明，在高酸性HNO溶液中，这两种配体对Am(III)均具有较强的萃取能力和对Eu(III)的高选择性。随着HNO浓度从1.0 M增加到4.0 M，这两种配体的分离因子(β)在17至26之间。斜率分析表明，3:1的配体/金属络合物是萃取过程中形成的主要物种。通过紫外可见光谱法和单晶结构分析法也确定了这两种配体与镧系元素形成的物种比例为3:1。Ph-MTP和BuPh-MTP与Nd(III)形成1:3络合物的稳定常数分别测定为7.06±0.015和6.67±0.007。利用单晶X射线衍射技术和DFT理论计算清晰地阐明了1:3络合物的几何结构。这项工作提供了一种通过在一个配体中组合两个不同官能团来设计新型不对称硬-软混合锕系元素萃取剂的有效策略，官能团与金属离子之间的相互作用机制有待进一步研究。
