Density functional modeling of Am3+/Eu3+ selectivity with diethylenetriaminepentaacetic acid and its bisamide chelates.
Density functional modeling of Am3+/Eu3+ selectivity with diethylenetriaminepentaacetic acid and its bisamide chelates.
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DOI：
10.1080/00223131.2020.1842267
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发表时间：
2020-11
影响因子：
1.2
通讯作者：
M. Kaneko;Y. Sasaki;M. Matsumiya;M. Nakase;K. Takeshita
中科院分区：
文献类型：
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作者：
M. Kaneko;Y. Sasaki;M. Matsumiya;M. Nakase;K. Takeshita
摘要采用密度泛函理论计算了金属离子与二乙烯三胺五乙酸（DTPA）及其双酰胺（DTPABA）配合物的分子结构和配合物形成反应模型，以了解金属离子对Am3+和Eu 3+的选择性。与DTPA和DTPABA螯合物的计算复合物再现实验晶体结构的配位几何。计算的络合物形成反应的吉布斯自由能表明，Am3+离子形成更高的稳定性比Eu 3+离子的螯合物，与实验结果相一致。Am3+对Eu 3+的选择性高于Eu 3+，这可能是由于Am3+ 5的f-轨道与N2 s，2 p-轨道之间有较大的键重叠.这意味着金属离子和供体原子之间的共价贡献区分络合物形成稳定性，导致Am3+/Eu 3+选择性。我们希望这项研究有助于系统化金属离子选择性的起源，并加速新的配体的探索。
ABSTRACT Density-functional theory calculations were applied to mo lecular structure and complex formation reaction modelings of metal ion complexes with diethylenetriaminepentaacetic acid (DTPA) and its bisamide (DTPABA) chelates to understand the metal ion selectivity between Am3+ and Eu3+. The calculated complexes with DTPA and DTPABA chelates reproduced the coordination geometries of experimental crystal structures. Calculated Gibbs free energies of the complex formation reactions indicated that Am3+ ion forms higher stable complexes with both chelates than Eu3+ ion, being consistent with the experimental results. The higher Am3+ selectivity over Eu3+ was suggested to originate in the larger bond overlap between Am3+ 5 f-orbital and N 2s, 2p-orbital. This means that the covalent contribution between the metal ion and donor atoms differentiates the complex formation stabilities, leading to the Am3+/Eu3+ selectivity. We expect that this study contributes to systematize the origin of metal ion selectivity and to accelerate novel ligand exploration.