Theoretical Insights on the Interaction of Uranium with Amidoxime and Carboxyl Groups
Theoretical Insights on the Interaction of Uranium with Amidoxime and Carboxyl Groups
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铀与偕胺肟和羧基相互作用的理论见解
DOI：
10.1021/ic500202g
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发表时间：
2014-09-15
影响因子：
4.6
通讯作者：
Shi, Wei-Qun
中科院分区：
文献类型：
--
作者：
Wang, Cong-Zhi;Lan, Jian-Hui;Shi, Wei-Qun
从海水中回收铀是极具挑战性的，但对于核能的持续发展至关重要，因此探索铀酰络合物的配位结构和成键性质对于设计高效的铀吸附剂至关重要。本文采用量子化学计算方法，系统地研究了不同烷基链上带有偕胺肟酸（AO（-））、羧基（Ac-）、戊二酰亚胺二肟酸（HA（-））和双官能团（AO（-））/Ac-、HA（-））/Ac-）的吸附剂与铀的相互作用。在所有的铀酰配合物中，AO（-）基团以单齿配位和eta（2）配位为主，Ac-基团以单齿和双齿配位为主。胺肟还可以形成环状酰亚胺二肟（H（2）A），其与UO 22+配位作为三齿配体。模型置换反应的动力学分析证实了萃取过程中的速率决定步骤，即偕胺肟基团与铀酰络合物[UO 2（CO 3）（3）]（4-）中碳酸根基团的解离相结合。与AO（-）基团的络合物种显示出更高的结合能比与Ac-基团的类似物。然而，根据与[UO_2（CO_3）（3）]（4-）作为反应物的反应，所获得的具有Ac-的铀酰络合物似乎更有利，这可能是由于HAO相比于HAc具有更高的稳定性。这也是具有混合官能团AO（-）/Ac-的物种比具有单配体的物种更稳定的原因。因此，如文献所报道的，偕胺肟和羧基的协同作用可以提高铀的吸附能力。
Recovery of uranium from seawater is extremely challenging but important for the persistent development of nuclear energy, and thus exploring the coordination structures and bonding nature of uranyl complexes becomes essential for designing highly efficient uranium adsorbents. In this work, the interactions of uranium and a series of adsorbents with various well-known functional groups including amidoximate (AO(-)), carboxyl (Ac-), glutarimidedioximate (HA(-)), and bifunctional AO(-))/Ac-, HA(-))/Ac-) on different alkyl chains (R'=CH3, R ''=C13H26) were systematically studied by quantum chemical calculations. For all the uranyl complexes, the monodentate and eta(2) coordination are the main binding modes for the AO(-) groups, while Ac- groups act as monodentate and bidentate ligands. Amidoximes can also form cyclic imide dioximes (H(2)A), which coordinate to UO22+ as tridentate ligands. Kinetic analysis of the model displacement reaction confirms the rate-determining step in the extraction process, that is, the complexing of uranyl by amidoxime group coupled with the dissociation of the carbonate group from the uranyl tricarbonate complex [UO2(CO3)(3)](4-). Complexing species with AO(-) groups show higher binding energies than the analogues with Ac- groups. However, the obtained uranyl complexes with Ac- seem to be more favorable according to reactions with [UO2(CO3)(3)](4-) as reactant, which may be due to the higher stability of HAO compared to HAc. This is also the reason that species with mixed functional group AO(-)/Ac- are more stable than those with monoligand. Thus, as reported in the literature, the adsorbability of uranium can be improved by the synergistic effects of amidoxime and carboxyl groups.