Hydrogen Migration Reaction in Reactive Organic and Organometallic Intermediates

将研究反应性有机和有机金属中间体中分子内氢迁移反应的机理基础。低温基质分离光谱、低温核磁共振光谱和时间分辨吸收光谱将被用来建立重排途径和表征反应物种。有机卡宾、有机硝烯和某些配位不饱和的16电子有机金属中间体组成了一类等效态的缺电子反应中间体，将被研究。在有机金属的研究中，将使用低温核磁共振跟踪反应的烯丙基氢化物中间体的化学以及这些物种在烯烃异构化过程中的参与。在金属有机中间体中加入了铁、钐和钌等金属原子。特别是，将针对烯丙基C-H和βC-H插入反应进行研究。在有机研究中，实验将集中在用时间分辨光谱直接观察卡宾和1，4-双自由基氢迁移反应。来自有机动力学项目的这笔资金支持威斯康星大学罗伯特·J·麦克马洪教授的工作。氢原子如何通过分子内过程在反应性缺电子有机和有机金属中间体中迁移的细节将被研究。这些难以捉摸的中间体将在低温下通过各种光谱方法进行研究，以表征整个反应中的中间体和各个步骤。将被研究的活性中间体包括卡宾(二价碳物种)、硝烯(单价氮物种)和有机金属中间体，它们有16个电子，而不是金属原子周围稳定的18电子补体。在金属有机中间体中加入了铁、钐和钌等金属原子。

The mechanistic basis underlying intramolecular hydrogen migration reactions in reactive organic and organometallic intermediates will be studied. Low-temperature matrix isolation spectroscopy, low- temperature NMR spectroscopy, and time-resolved absorption spectroscopy will be used to establish rearrangement pathways and to characterize the reactive species. Organic carbenes, organic nitrenes, and certain coordinately unsaturated 16-electron organometallic intermediates comprise an isolobal class of electron-deficient reactive intermediates that will be studied. In the organometallic studies, low-temperature NMR will be used to follow the chemistry of reactive allyl hydride intermediates and the involvement of these species in alkene isomerization processes. Iron, Osmium, and Ruthenium metal atoms will be incorporated in the organometallic intermediates. In particular, studies will be directed to allylic C-H and beta C-H insertion reactions. In the organic studies, experiments will focus on direct observation of hydrogen migration reactions of carbenes and 1,4-biradicals by time-resolved spectroscopy. %%% This grant from the Organic Dynamics Program supports the work of Professor Robert J. McMahon at the University of Wisconsin. The details of how hydrogen atoms migrate in reactive electron- deficient organic and organometallic intermediates by intramolecular processes will be studied. These elusive intermediates will be studied at low temperatures by various spectroscopic methods in order to characterize the intermediates and individual steps in the overall reaction. The reactive intermediates that will be studied include carbenes (divalent carbon species), nitrenes (monovalent nitrogen species), and organometallic intermediates that have 16 electrons rather than the stable 18-electron complement about the metal atom. Iron, Osmium, and Ruthenium metal atoms will be incorporated in the organometallic intermediates.