The design of molecular complexes of earth-abundant first-row transition metals that can catalyze multi-electron C–H bond activation processes is of interest for achieving efficient, low-cost syntheses of target molecules. To overcome the propensity of these metals to perform single-electron processes, redox-active ligands have been utilized to provide additional electron equivalents. Herein, we report the synthesis of a novel redox active ligand, [ibaps]3–, which binds to transition metals such as FeII and CoII in a meridional fashion through the three anionic nitrogen atoms and provides additional coordination sites for other ligands. In this study, the neutral bidentate ligand 2,2′-bipyridine (bpy) was used to complete the coordination spheres of the metal ions and form NEt4[MII(ibaps)bpy] (M = Fe (>1) or Co (>1-Co)) salts. The FeII salt exhibited rich electrochemical properties and could be chemically oxidized by 1 and 2 equiv. of ferrocenium to form singly and doubly oxidized species, respectively. The reactivity of >1 towards intramolecular C–H bond amination of aryl azides at benzylic and aliphatic carbon centers was explored, and moderate to good yields of the resulting indoline products were obtained.
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机译:能够催化多电子C–H键活化过程的富含地球的第一行过渡金属的分子配合物的设计对于实现目标分子的高效,低成本合成很有意义。为了克服这些金属进行单电子过程的倾向,已利用氧化还原活性配体提供额外的电子当量。在此,我们报道了一种新型的氧化还原活性配体[ibaps] 3- sup>的合成,该配体与诸如Fe II sup>和Co II之类的过渡金属结合 strong>通过三个阴离子氮原子以子午线方式提供并且为其他配体提供了额外的配位点。在这项研究中,中性双齿配体2,2'-联吡啶(bpy)用于完成金属离子的配位球并形成NEt4 [M II sup>(ibaps)bpy](M = Fe (> 1 strong>)或Co(> 1 strong> -Co))盐。 Fe II sup>盐具有很强的电化学性能,可以被1和2当量化学氧化。的二茂铁分别形成单一和双重氧化物质。探索了> 1 strong>对芳基叠氮化物在苄基和脂肪族碳中心的分子内C–H键胺化的反应性,并获得了中等至良好收率的吲哚啉产物。
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