中文摘要：

比较了BP86、PBE、B3LYP、B3PW91、BHandHLYP、PBE0、X3LYP、CAM-B3LYP、TPSS、M06L、M06和M06-2X等12种采用了广义梯度近似（GGA、hybrid GGA、meta-GGA和hybrid meta-GGA）的密度泛函理论（DFT）方法在三个三价铀复合物表征中的应用。研究模型采用铀复合物催化CO2和CS2官能团化反应中的三个中间体（Tp＊）2U-η1-CH2Ph （Cpd2），（Tp＊）2U-κ2-O2CCH2Ph （Cpd3）和（Tp＊）2U-κ2-S2CCH2Ph （Cpd4）。研究发现， B3LYP和B3PW91在几何结构和电子结构方面优于其它方法。基于分子轨道理论的MP2方法在Cpd2和Cpd3的表征中给出与DFT方法相近的结果，而在Cpd4的表征中表现出较大的差异。这可能是由于同样是单参考态方法的MP2捕捉到了与DFT方法不同的电子结构。同时，通过对比分别采用小核赝势（5f-in-valence）和大核赝势（5f-in-core）基组处理铀原子的计算结果，发现对测试的模型体系，两种处理方法可获得相近的热力学能量。与以往主要关注高价态锕系复合物的处理方法的评估工作不同，本项工作适应逐渐增加的对低价态锕系分子体系的研究的需求，对12种常用的密度泛函理论方法在低价态锕系复合物研究中的应用进行了评估，期望为处理类似体系的研究工作提供参考。

英文摘要：

We report a comparative study on the characterization of three trivalent uranium complexes using 12 density functional theory （DFT） methods, i.e., BP86, PBE, B3LYP, B3PW91, BHandHLYP, PBE0, X3LYP, CAM-B3LYP, TPSS, M06L, M06, and M06-2X, representing （meta-）GGA and hybrid （meta-）GGA levels of treatment of molecular systems. The MP2 method was used in single-point calculations to provide an ab initio view of the electronic structure. Three model systems in the experimental work on the activation of CO2 and CS2 by a trivalent uranium complex （Tp＊）2U-η1-CH2Ph （Cpd2） were used i.e., （Tp＊）2U-η1-CH2Ph （Cpd2）, （Tp＊）2U-κ2-O2CCH2Ph （Cpd3）, and （Tp＊）2U-κ2-S2CCH2Ph （Cpd4） （Tp=hydrotris（3,5-dimethylpyrazolyl）borate）. The hybrid functionals, B3LYP and B3PW91, displayed good performance in view of both the geometrical and electronic＆amp;nbsp;structures. The MP2 method generated consistent results as DFT methods for Cpd2 and Cpd3, while provided an odd picture of the electronic structure of Cpd4 that may be due to its single determinant feature, leading to its capture of an electronic configuration of Cpd4 different from the one with the DFT methods. The use of a quasi-relativistic 5f-in-core ECP （LPP） treatment for U（III） in the thermodynamic calculations was supported by the calculations with a smal-core ECP treatment （SPP） for U. Owing to increasing interests in low-valent actinide molecular systems, this work complements previous comparative studies, which mainly focus on high-valent actinide complexes, and provides timely information on the performance of 12 widely used DFT methods in studying low-valent actinide systems. It is expected to contribute to a more sensible selection of DFT methods in the study of low-valent actinide molecular systems.