COMPARATIVE PHOTO-INDUCED OXIDATIVE ADDITION OF B-H, C-H, Si-H AND B-B BONDS

B-H、C-H、Si-H 和 B-B 键的比较光诱导氧化加成

基本信息

批准号：
EP/F037740/1
负责人：
Robin Perutz
金额：
$ 65.71万
依托单位：
University of York
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FF037740%2F1
关键词：
COMPARATIVE PHOTO INDUCED OXIDATIVE ADDITION

项目摘要

A knowledge of reaction mechanisms is what enables chemists to predict the outcome of new reactions and work out how to make new compounds most effectively. Transition-metal compounds containing metals such as rhodium and ruthenium are used extensively as catalysts for organic and industrial processes. Oxidative addition reactions form a well-known class of reactions of such catalysts. There are two major developments in oxidative addition reactions that this project addresses: (1) the development of catalytic reactions of the simplest hydrocarbons (e.g. benzene or pentane) with boron compounds that yield very useful products for further reactions (2) the realisation that oxidative addition reactions sometimes proceed via non-classical intermediates called sigma complexes ; for instance, a silane may bind to the metal without breaking the silicon-hydrogen bond in the intermediate sigma-complex, although it is completely broken in the product. Firstly, in proof of principle experiments, we have demonstrated that we can make rhodium compounds that contain right-handed ligands. We can then obtain oxidative addition products that have metal centres that are either right-handed or left-handed and can monitor exchange of these two isomers. This exchange process tells us about the existence of intermediates (or transition states) with a mirror plane. With the help of theory and experiment we can infer the existence of sigma complexes. Secondly, this proposal addresses the question of what is special about boron by measuring the rates of reaction of carefully selected transition metal compounds with the boron compounds using a short light pulse to initiate the reactions. The results will be interpreted with the aid of theoretical calculations carried out in collaboration with Eisenstein, a well-known theorist. Thirdly, we will use NMR spectroscopy to determine the distribution of products when different combinations of reagents are in competition, for instance allowing silicon and boron compounds to compete for the same transition metal species. Finally, we will investigate transition metal complexes that are claimed to be suitable for two oxidative addition reactions in succession. These precursor complexes react on irradiation of light and it would be especially interesting for applications if they can be initiated with visible light rather than ultra-violet light. Overall, this study will give us a detailed picture of the relationships between different types of oxidative addition reactions that can be fed into catalyst design.

对反应机制的了解是使化学家能够预测新反应的结果并确定如何最有效地制造新化合物的结果。含有金属（例如菱形和磺氮）的过渡金属化合物被广泛用作有机和工业过程的催化剂。氧化添加反应形成了此类催化剂的一类众所周知的反应。氧化添加反应有两个主要发展，该项目解决了：（1）最简单的碳氢化合物（例如苯或戊烷）与硼化合物的催化反应的发展，这些反应产生了非常有用的产物，以进一步反应（2）意识到氧化添加有时会通过非经典中间体中的氧化反应而产生，这些反应有时会通过称为Sigmaemplace的非经典媒介中间人进行氧化反应；例如，硅烷可以与金属结合，而不会破坏中间sigma-complex中的硅 - 氢键，尽管它在产品中完全破裂。首先，为了证明原理实验，我们证明了我们可以制造含有右手配体的菱形化合物。然后，我们可以获得具有右手或左撇子的金属中心的氧化添加产品，并且可以监视这两个异构体的交换。这个交换过程告诉我们有关中间体（或过渡状态）的存在。在理论和实验的帮助下，我们可以推断出Sigma复合物的存在。其次，该提案通过使用短的光脉冲来启动反应，来解决硼龙与硼化合物的反应速率，以解决有关硼的特殊问题。结果将在与著名理论家爱森斯坦合作进行的理论计算的帮助下进行解释。第三，我们将使用NMR光谱法来确定当试剂的不同组合在竞争中，例如允许硅和硼化合物竞争相同的过渡金属物种时。最后，我们将研究过渡金属复合物，这些金属复合物被认为是连续的两个氧化添加反应。这些前体配合物在光照射下反应，如果可以用可见光而不是超紫罗莱氏光来启动它们，对于应用而言，这将特别有趣。总体而言，这项研究将使我们详细介绍了可以馈入催化剂设计的不同类型的氧化添加反应之间的关系。