Skeletal Rearrangement Process in Organometallic Cations of Group 14 Elements - A Powerful Concept for Assembling Complex Polysilane Frameworks

尽管聚硅烷具有非常有趣的电子性质和技术潜力，但化学家对其合成或结构操纵的技能大多局限于Wurtz型偶联反应。在这方面，路易斯酸催化的重排反应代表了一种有趣的方法来获得分子结构，否则很难获得。与众所周知的Wagner-Meerwein重排密切相关，这是一个更容易的聚硅烷过程。尽管聚硅烷重排的第一个例子在近40年前就有报道，但人们对这种反应的支配原理知之甚少。目前的项目将由奥尔登堡和格拉茨的小组进行，提出一项联合研究，包括新的合成方法，中间产物和反应机制的调查，两者都由计算方法支持。初步研究表明，同分异构体聚硅烷与氯化铝反应可形成相当复杂的结构，如金刚烷型三环聚硅烷。此外，发现含锗的聚硅烷随着锗原子选择性地移动到产物的三烷基化位置而重排。其他初步结果表明，Lewis酸催化反应也可用于合成含烷基单元的聚硅烷，甚至进一步用于制备复合碳硅烷。这个项目中的合成工作，由奥地利小组进行，将受益于（德国小组）的理论和基础研究，这将提供对化学基本原理的见解。另一方面，综合作业将允许提出新的问题，这些问题将由计算方法来解决。这两组独特的合成和理论专业知识的结合将使刘易斯酸催化重排反应的复杂物质得到最好的处理。

Despite the highly interesting electronic properties and the technological potential of polysilanes the chemist’s repertoire for their synthesis or structural manipulation is mostly limited to the Wurtz type coupling reaction. In this connection Lewis acid catalyzed rearrangement reactions represent an interesting method to access molecular structures, which are otherwise difficult to obtain. Closely related to the well know Wagner-Meerwein rearrangement, it is a much more facile process for polysilanes. Although first examples of polysilane rearrangement have been reported almost 40 years ago not much is known about the governing principles of this reaction. The current project, to be carried out by the groups in Oldenburg and Graz, proposes a joint study comprising new synthetic approaches, investigations of intermediates and reaction mechanisms, both supported by computational methods. Preliminary studies have already shown that the reaction of isomeric polysilanes with aluminum chloride can result in the formation of rather complex structures such as an adamantane type tricyclic polysilane. In addition it was found that germanium containing polysilanes rearrange with the germanium atoms selectively moved to trisilylated positions of the product.Other preliminary results suggest the Lewis acid catalyzed reaction can also be used for the synthesis of polysilanes containing alkylene units and even further for the preparation of complex carbosilanes. The synthetic work in this project, conducted by the Austrian group, will benefit from the theoretical and basic studies (of the German group) which will provide insight into the underlying principles of the chemistry. On the other hand will the synthetic work allow formulating new questions which will be addressed by computational methods. The unique combined synthetic and theoretical expertise of the two groups will allow the best possible treatment of the complex matter of Lewis acid catalyzed rearrangement reactions.