Theoretical Studies on Uranyl Macrocyclic Ligand Complexes

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.