铀酰大环配体化合物的理论研究进展

    Theoretical Studies on Uranyl Macrocyclic Ligand Complexes

    • 摘要: 锕酰离子与配体的相互作用本质在锕系元素组分离的应用中具有重要意义,因此本课题组近几年一直致力于这方面的研究。本文对铀酰与大环配体形成的配合物的配位结构、稳定性和成键性质进行了综述和规律性总结。首先,研究发现锕酰大环配合物的配位结构取决于大环配体的腔体大小;其次,侧配位时,铀酰倾向于形成1∶2稳定结构,而嵌入式结构时,铀酰倾向于形成1∶1稳定结构;再次,通过对一系列配体的研究,发现环尺寸为18的配体,在与铀酰结合时表现了优异的配位能力,其中[CHP]4-具有最强的结合能力;最后,这种稳定主要是由于U-N共价性大于U-O及U-S。这些结构规律和成键特征,为实验上筛选合理且高效分离锕系元素的配体提供了重要理论指导。

       

      Abstract: The nature of the interaction between actinide ions and ligands is of great significance in the application of the separation of actinide groups. Therefore, we have been devoted to this aspect in recent years. In this article, the coordination structure, stability and bonding properties of the complexes formed by uranyl and macrocyclic ligands are reviewed. First of all, our study found that the coordination structure of actinyl macrocyclic complexes depends on the size of the macrocyclic ligands; secondly, in the case of “side-on” coordination, uranyl tends to form a 1∶2 complex, while in the case of “insertion” structure, uranyl tends to form a 1∶1 complex; thirdly, it has been found that the ligands with ring size of 18 have excellent coordination ability when combined with uranyl, and [CHP]4- has the strongest binding ability; finally, this stability is mainly due to the greater covalence of U-N than that of U-O and U-S. These structural rules and bonding characteristics provide important theoretical guidance for the experimental screening of reasonable and efficient ligands for the separation of actinides.

       

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