Density Functional Calculations on Metallabenznenes

金属杂芳香化学是当前金属有机化学的研究热点之一，金属苯作为一类重要的金属杂芳香化合物，其独特的结构和潜在的应用前景受到人们广泛关注。通过系统的密度泛函理论计算，我们研究了几类金属苯的结构及其稳定性，考察了过渡金属改变、金属中心配位环境的变化、芳环上氢原子的取代、芳环上碳原子取代等结构修饰对不同自旋态金属苯相对稳定性的影响。此外，我们对中心金属为Fe、Ru、Os的六配位硅杂金属苯和中心金属为Co、Rh、Ir的五配位硅杂金属苯进行了初步的计算研究，讨论了a位硅杂金属苯的芳香性。获得的主要结果如下： 1.计算表明，影响金属苯单重态与三重态相对稳定性的最大因素是其过渡金属中心的改变，第一过渡系的金属...Metallaaromatics have attracted considerable attention in the organometallic chemistry. Metallabenzenes, as a key type of transition-metal-containing aromatic compounds, exhibit novel structural features and potential applications in chemistry and advanced materials, and many metallabenzenes have been synthesized successfully in the past decades. Herein extensive density functional calculations we...学位：理学硕士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：2052008115171

Stabilization of anti-aromatic and strained five-membered rings with a transition metal

1981年诺贝尔化学奖获得者、美国康奈尔大学RoaldHoffmann教授评价该项工作说：'The　paper is an excellent one--it's　quite a mazing that the parent Os　system,molecule 1,chooses to give the osmapentalyne'。德国化学家Uwe Rosenthal教授等在同期《自然—化学》杂志的《News and Views》栏目以《Breaking the rules》为题撰文评述了这一研究成果。全文地址：http://www.nature.com/nchem/journal/vaop/ncurrent/pdf/nchem.1702.pdfAnti-aromatic compounds, as well as small cyclic alkynes or carbynes, are particularly challenging synthetic goals. The combination of their destabilizing features hinders attempts to prepare molecules such as pentalyne, an 8π-electron anti-aromatic bicycle with extremely high ring strain. Here we describe the facile synthesis of osmapentalyne derivatives that are thermally viable, despite containing the smallest angles observed so far at a carbyne carbon. The compounds are characterized using X-ray crystallography, and their computed energies and magnetic properties reveal aromatic character. Hence, the incorporation of the osmium centre not only reduces the ring strain of the parent pentalyne, but also converts its Hückel anti-aromaticity into Craig-type Möbius aromaticity in the metallapentalynes. The concept of aromaticity is thus extended to five-membered rings containing a metal–carbon triple bond. Moreover, these metal–aromatic compounds exhibit unusual optical effects such as near-infrared photoluminescence with particularly large Stokes shifts, long lifetimes and aggregation enhancement