环戊二烯基锕系配合物结构和还原性质的密度泛函理论研究  

Density functional theory study of structural and redox properties of cyclopentadienyl actinide complexes

作　　者：杨俊杰 马莉雯 杨光露 卜赫 郝璐祎 郭元茹[1] 潘清江[2] YANG Jun-Jie;MA Li-Wen;YANG Guang-Lu;BU He;HAO Lu-Yi;GUO Yuan-Ru;PAN Qing-Jiang(College of Material Science and Engineering,Northeast Forestry University,Harbin 150040,China;School of Chemistry and Materials Science,Heilongjiang University,Harbin 150080,China)

机构地区：[1]东北林业大学材料科学与工程学院,哈尔滨150040 [2]黑龙江大学化学化工与材料学院,哈尔滨150080

出　　处：《黑龙江大学工程学报》2020年第4期24-31,37,共9页Journal of Engineering of Heilongjiang University

基　　金：东北林业大学大学生创新项目(S202010225078);国家自然科学基金项目(21671060)。

摘　　要：深入理解锕系有机金属配合物的结构和化学反应性质对锕系配位化学的发展至关重要。运用密度泛函理论系统计算了环戊二烯基配位铀化合物,[Cp3UmX]n(X=F, Cl, Br, I;m=Ⅲ, n=-1;m=Ⅳ, n=0)和[Cp3UmX]n(X=Vacant;m=Ⅲ, n=0;m=Ⅳ, n=+1)。异构体优化表明四价和三价铀配合物分别对应三重态和四重态基态。与四价铀配合物的结构参数相比较,三价的U-C、U-Cpcent和U-X距离更长;这与UⅢ离子半径长于UⅣ的相一致。基于电子密度的原子在分子中量子理论计算指认U-X间为配位单键本质。电子自旋密度分析揭示单电子反应为金属铀主导、Cp配体参与的还原机制。研究发现,随着配体X从F、Cl、Br、I变化到Vacant(空置未配位),配合物的还原电势(E0)逐渐变小,并进一步建立了E0与U-Cp作用强度之间的正相关规律性。同时考虑溶剂化和自旋-轨道耦合效应时,计算的还原电势在报道的实验值范围内。另外,变换金属并计算了[Cp3Anm]n(An=U, Np, Pu;m=Ⅲ, n=0;m=Ⅳ, n=+1)结构和还原性质,得到的还原电势值随U、Np、Pu依次增大,与实验测得的An4+/An3+离子E0值趋相一致。The in-depth understanding of structures and chemical reactivity properties of organoactinides is of great importance in developing actinide coordination chemistry. A series of low-valence complexes have been systematically investigated, [Cp3UmX]n(X=F, Cl, Br and I;m=Ⅲ, n=-1;m=Ⅳ, n=0) and [Cp3UmX]n(X=Vacant;m=Ⅲ, n=0;m=Ⅳ, n=+1), using density functional theory. Optimizations on various possible electron-spin isomers confirmed the triplet ground state for tetravalent uranium complexes and the quartet one for trivalent anlogues. Compared with those of tetravalent uranium complexes, distances of U-C, U-Cpcent and U-X of trivalent complexes are longer, in consistent of the manner that the radius of UⅢ ion is longer than the one of UⅣ. Calculations under the quantum theory of atoms-in-molecule(QTAIM) recognized the intrinsic U-X dative single bond. It was found from electron-spin density that the single-electron reduction is dominated by uranium center mixed with some Cp contribution. Reduction potentials(E0) were calculated to gradually decrease in going from X=F, Cl, Br, I to Vacant. It was built that E0 is positively correlated with the interaction strength between U and Cp. Considering both solvation and spin-orbit coupling effects, calculated E0 values fall well within the range of reported experimental values. Additionally, [Cp3Anm]n(An=U, Np, Pu;m=Ⅲ, n=0;m=Ⅳ, n=+1) were computationally explored for comparison. Their E0 values increase along U, Np and Pu, agreeing with experimentally measured ones of An4+/An3+ couples.

关 键 词：环戊二烯基配体 低价锕系配合物 原子在分子中的量子理论 还原机制 密度泛函计算 

分 类 号：O614.35[理学—无机化学]