三明治型四聚吡咯低价铀配合物结构、成键和氧化还原性质的相对论密度泛函理论研究

发布时间：2018-05-06 13:45

本文选题：三明治型四聚吡咯低价铀配合物 + 异构体稳定性　；参考：《黑龙江大学自然科学学报》2017年05期

【摘要】：使用密度泛函理论(B3LYP)方法,结合准相对论有效核势(ECP)和二分量ZORA相对论Hamiltonian,探索三明治型四聚吡咯铀配合物LUmL'(配体为porphyrizine或porphyrine;m=III和IV)的结构、成键和反应性质。优化多种空间和"电子自旋态"异构体结构,发现铀配合物具有交叉式、高电子自旋态的基态。QTAIM(Quantum theory of atoms in molecule)的U-N键临界点处的电子/能量密度拓扑分析以及counterpoise计算U-N作用能,揭示该化学键为弱极性共价键。计算显示在采用适当的三价和四价铀源和强碱性配体时,可经过放热反应生成配合物。考虑溶剂(苯、THF和水)和旋-轨耦合影响,计算从四价铀配合物到三价的还原电势,得到数值均小于1 V,这与四价配合物相对稳定、三价铀配合物具有强还原性的实验结果相符合。研究发现降低溶剂极性,配合物的还原电势向负方向移动,这可为实验中采用溶剂极性来调控配合物的氧化还原性质提供理论指导。
[Abstract]:The structure, bonding and reaction properties of the sandwich type tetrapolypyrrole uranium complexes LUmLN (ligands porphyrizine or porphyrinetima-III and IV) were investigated by using density functional theory (DFT) method, combined with quasi-relativistic effective nuclear potential (ZORA) and two-component ZORA relativistic Hamiltonian. By optimizing the structures of many kinds of space and "electron spin state" isomers, it is found that uranium complexes have cross formula, electron / energy density topological analysis at the critical point of U-N bond of high electron spin state. QTAIMI Quantum theory of atoms in molecule) and counterpoise calculation of U-N interaction energy. It is revealed that the chemical bond is a weakly polar covalent bond. The results show that the complex can be formed by exothermic reaction when suitable trivalent and tetravalent uranium sources and strong alkaline ligands are used. Considering the effect of solvent (benzene THF and water) and rotation-orbit coupling, the reduction potential from tetravalent uranium complex to trivalent is calculated, and the values are less than 1 V, which are relatively stable with tetravalent complexes. The experimental results of the trivalent uranium complexes are in good agreement with the experimental results. It is found that the reduction potential of the complex shifts to a negative direction by reducing the solvent polarity, which can provide theoretical guidance for the use of solvent polarity to regulate the redox properties of the complexes.
【作者单位】：黑龙江大学化学化工与材料学院功能无机材料化学教育部重点实验室;黑龙江省大庆水文局水环境监测分中心;
【基金】：国家自然科学基金资助项目(21273063) 黑龙江省留学回国人员科技项目择优资助项目
【分类号】：O641.4

【相似文献】