化学学报 ›› 2025, Vol. 83 ›› Issue (12): 1523-1529.DOI: 10.6023/A25080276 上一篇    下一篇

研究论文

二价锕系配合物AnB8的理论研究

张乃心a,b, 石伟群a,b,c,*(), 王聪芝b,*()   

  1. a 哈尔滨工程大学 核科学与技术学院 黑龙江 哈尔滨 150001
    b 中国科学院高能物理研究所 核能放射化学实验室 核能放射化学实验室 北京 100049
    c 上海交通大学 机械与动力工程学院核燃料循环与核材料研究所 机械与动力工程学院核燃料循环与核材料研究所 上海 200240
  • 投稿日期:2025-08-10 发布日期:2025-10-10
  • 基金资助:
    国家自然科学基金(12175269)

Theoretical Studies of Divalent Actinide Complexes AnB8

Naixin Zhanga,b, Weiqun Shia,b,c,*(), Congzhi Wangb,*()   

  1. a College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001, China
    b Laboratory of Nuclear Energy Chemistry, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
    c Institute of Nuclear Fuel Cycle and Materials, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2025-08-10 Published:2025-10-10
  • Contact: * E-mail: shiwq@ihep.ac.cn;wangcongzhi@ihep.ac.cn
  • Supported by:
    National Natural Science Foundation of China(12175269)

由于硼元素具有缺电子特性, 随尺寸变化硼团簇呈现多种多样的结构, 不同金属的掺杂能够进一步丰富硼团簇的结构和性质. 通过全局最优结构搜索和密度泛函理论(DFT)方法研究了一系列锕系金属掺杂硼团簇AnB8 (An=Ac, Th, Am, Cm). 研究发现, 每个AnB8团簇都具有半夹心和椅状结构两种构型, 除ThB8外, AcB8、AmB8和CmB8的半夹心结构最稳定, 而ThB8的两种结构能量差异较小. 这些硼团簇的半夹心结构均为稳定的MII[${B}_{8}^{2-}$]型二价锕系配合物, 而且${B}_{8}^{2-}$配体具有σ和π双重芳香性. 成键性质分析表明, 所有配合物中An—B之间存在共价相互作用, 而且ThB8的共价相互作用更强. 所有配合物都具有较高的稳定性, 尤其是ThB8. 这些结果表明, ${B}_{8}^{2-}$配体能够稳定二价锕系元素.

关键词: 硼团簇, 金属掺杂, 锕系元素, 密度泛函理论, 全局最优结构搜索

Due to the electron-deficient characteristics of boron, boron clusters exhibit a variety of structures with size changes, and the doping of different metal atoms can further enrich the structures and properties of boron clusters. We investigated a series of actinide metal-doped boron clusters AnB8 (An=Ac, Th, Am, Cm) by using the global minimum structural searches and density functional theory (DFT) methods. For each isomer, different spin states were considered at the PBE0/6-311+G*/RECP and TPSSH/6-311+G*/RECP theoretical levels. It is found that each AnB8 cluster possesses two configurations, half-sandwich and chair-like structures. Except for ThB8, the half-sandwich structures of AcB8, AmB8 and CmB8 are more stable, while the energy difference between the two structures of ThB8 is small, indicating that both may coexist in experiments. The half-sandwich structures of AcB8, ThB8, AmB8, and CmB8 correspond to doublet, singlet, octet, and nonet states, respectively. ThB8 is a closed-shell singlet system, in which the electronic configuration of the Th element may be [Rn]6d2. Voronoi deformation density (VDD) and Hirshfeld charges suggest that charge flows from the actinide elements to the boron ligands. The half-sandwich structures of these boron clusters are stable MII[${B}_{8}^{2-}$]-type divalent actinide complexes. Molecular orbital (MO) analysis shows that the An—B bonding orbitals of AcB8 and ThB8 mainly originate from An 6d orbitals, while those of AmB8 and CmB8 are primarily contributed by An 5f orbitals. Other analyses of bonding properties also indicate that there exist covalent interactions between An and B atoms in all complexes, and ThB8 has stronger covalent interactions. For these AnB8 complexes, the ${B}_{8}^{2-}$ ligands show double aromaticity features, which have six delocalized σ electrons and six delocalized π electrons. According to dissociation energy analysis, all the AnB8 complexes are highly stable, especially ThB8. These results indicate that the ${B}_{8}^{2-}$ ligands are capable of stabilizing the divalent actinides.

Key words: boron clusters, metal doping, actinides, density functional theory, global minimum structural search