Metsänen Toni T, Gallego Daniel, Szilvási Tibor, Driess Matthias, Oestreich Martin
Institut für Chemie , Technische Universität Berlin , Straße des 17. Juni 115 , 10623 Berlin , Germany . Email:
Department of Inorganic and Analytical Chemistry , Budapest University of Technology and Economics , Szent Gellért tér 4 , 1111 Budapest , Hungary.
Chem Sci. 2015 Dec 1;6(12):7143-7149. doi: 10.1039/c5sc02855h. Epub 2015 Sep 14.
Combined experimental and theoretical analysis of the carbonyl hydrosilylation catalysed by an iron(0) pincer complex reveals an unprecedented mechanism of action. The iron(0) complex is in fact a precatalyst that is converted into an iron(ii) catalyst through oxidative addition of a hydrosilane. Neither the hydrogen atom nor the silicon atom bound to the iron(ii) centre are subsequently transferred onto the carbonyl acceptor, instead remaining at the sterically inaccessible iron(ii) atom throughout the catalytic cycle. A series of labelling, crossover and competition experiments as well as the use of a silicon-stereogenic hydrosilane as a stereochemical probe suggest that the iron(ii) site is not directly involved in the hydrosilylation. Strikingly, it is the silyl ligand attached to the iron(ii) atom that acts as a Lewis acid for carbonyl activation in this catalysis. The whole catalytic process occurs on the of the transition metal. Computation of the new as well as plausible alternative and sphere mechanisms support the experimental findings.
对铁（0）钳形配合物催化的羰基硅氢化反应进行的实验与理论相结合的分析揭示了一种前所未有的作用机制。实际上，铁（0）配合物是一种前催化剂，通过硅烷的氧化加成转化为铁（II）催化剂。与铁（II）中心相连的氢原子和硅原子随后都不会转移到羰基受体上，而是在整个催化循环中始终保留在空间位阻较大的铁（II）原子上。一系列标记、交叉和竞争实验以及使用硅立体异构硅烷作为立体化学探针表明，铁（II）位点并不直接参与硅氢化反应。引人注目的是，连接在铁（II）原子上的硅基配体在该催化反应中作为羰基活化的路易斯酸。整个催化过程发生在过渡金属的 上。对新的 以及合理的替代 和 球机制的计算支持了实验结果。
（原文中部分内容缺失，可能影响完整理解，你可以补充完整后再让我翻译）
