Greif Gerlinde, Sauerwein Fynn S, Weßling Patrik, Duckworth Tamara M, Patzschke Michael, Gericke Robert, Sittel Thomas, März Juliane, Wilden Andreas, Modolo Giuseppe, Panak Petra J, Roesky Peter W
Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstr. 15, 76131 Karlsruhe, Germany.
Institute of Fusion Energy and Nuclear Waste Management─Nuclear Waste Management (IFN-2), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
Inorg Chem. 2024 Aug 19;63(33):15259-15269. doi: 10.1021/acs.inorgchem.4c01793. Epub 2024 Aug 5.
Here, we report the synthesis of the 6-(6-methyl-1,2,4,5-tetrazine-3-yl)-2,2'-bipyridine (MTB) ligand that has been developed for lanthanide/actinide separation. A multimethod study of the complexation of MTB with trivalent actinide and lanthanide ions is presented. Single-crystal X-ray diffraction measurements reveal the formation of [Ce(MTB)(NO)], [Pr(MTB)(NO)HO], and [Ln(MTB)(NO)MeCN] (Ln = Nd, Sm, Eu, Gd). In addition, the complexation of Cm(III) with MTB in solution was studied by time-resolved laser fluorescence spectroscopy. The results show the formation of [Cm(MTB)] complexes, which occur in two different isomers. Quantum chemical calculations reveal an energy difference between these isomers of 12 kJ mol, clarifying the initial observations made by time-resolved laser fluorescence spectroscopy (TRLFS). Furthermore, quantum theory of atoms in molecules (QTAIM) analysis of the Cm(III) and Ln(III) complexes was performed, indicating a stronger covalent contribution in the Cm-N interaction compared to the respective Ln-N interaction. These findings align well with extraction data showing a preferred extraction of Am and Cm over lanthanides (e.g., max. = 8.3) at nitric acid concentrations <0.1 mol L HNO.
在此，我们报告了用于镧系/锕系元素分离的6-(6-甲基-1,2,4,5-四嗪-3-基)-2,2'-联吡啶（MTB）配体的合成。本文介绍了MTB与三价锕系和镧系离子络合的多方法研究。单晶X射线衍射测量揭示了[Ce(MTB)(NO)]、[Pr(MTB)(NO)HO]和[Ln(MTB)(NO)MeCN]（Ln = Nd、Sm、Eu、Gd）的形成。此外，通过时间分辨激光荧光光谱研究了溶液中Cm(III)与MTB的络合。结果表明形成了[Cm(MTB)]络合物，其以两种不同的异构体形式存在。量子化学计算揭示了这些异构体之间的能量差为12 kJ/mol，阐明了时间分辨激光荧光光谱（TRLFS）的初步观察结果。此外，对Cm(III)和Ln(III)络合物进行了分子中原子的量子理论（QTAIM）分析，表明与相应的Ln-N相互作用相比，Cm-N相互作用中的共价贡献更强。这些发现与萃取数据非常吻合，萃取数据表明在硝酸浓度<0.1 mol/L HNO时，镅和锔比镧系元素更易被萃取（例如，最大分配系数 = 8.3）。
