A Quasi-relativistic Density Functional Theory Study of the Actinyl(VI, V) (An = U, Np, Pu) Complexes with a Six-Membered Macrocycle Containing Pyrrole, Pyridine, and Furan Subunits

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• 作者：Jian-Hui Lan ; Cong-Zhi Wang ; Qun-Yan Wu ; Shu-Ao Wang ; Yi-Xiao Feng ; Yu-Liang Zhao ; Zhi-Fang Chai ; Wei-Qun Shi
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：August 27, 2015
• 年：2015
• 卷：119
• 期：34
• 页码：9178-9188
• 全文大小：548K
• ISSN：1520-5215

文摘

Actinyl(VI, V) (An = U, Np and Pu) complexes of the recently reported hybrid macrocycle, cyclo[1]furan[1]pyridine[4]pyrrole (denoted as H₄L), have been studied using density functional theory in combination with the small-core scalar-relativistic effective core potentials and corresponding (14s13p10d8f6g)/[ 10s9p5d4f3g] basis sets in the segmented contraction scheme. On the basis of our calculations, the pyrrole nitrogen atoms that possess the shortest An-L bonds and strongest basicity are the main donor atoms that contribute to the formation of actinyl(VI, V) complexes. The natural population analysis (NPA) suggests higher ligand-to-actinyl charge transfer in the actinyl(VI) complexes than in their actinyl(V) analogues, which account for the higher decomposition energies of the former. A significant actinide-to-ligand spin density delocalization in the uranyl(V) and neptunyl(V) complexes was observed owing to the redistribution of spin density caused by complexation. A thermodynamic analysis indicates that the formation of the actinyl(VI, V) complexes are exothermic reactions in CH₂Cl₂ solvent, where the uranyl cations show the highest selectivity. In aqueous solution containing chloride ions, for complexing with macrocycle H₄L, the plutonyl(VI) and uranyl(V) cations possess the highest selectivity among actinyl(VI) and (V) cations, respectively. This work can shed light on the design of macrocycle complexes for actinide recognition and extraction in the future.