Department of Chemistry , Texas A&M University , College Station , Texas 77843 , United States.
ChemMatCARS , University of Chicago c/o APS/ANL, Argonne , Illinois 60439 , United States.
J Am Chem Soc. 2019 Oct 16;141(41):16232-16236. doi: 10.1021/jacs.9b09064. Epub 2019 Oct 2.
The fleeting lifetimes of reactive intermediates in C-H functionalization chemistry often prevent their direct characterization. For example, the critical nitrenoid intermediates that mediate Rh-catalyzed C-H amination have eluded characterization for more than 40 years. In the absence of structural characterization of these species, methodological development is often computationally guided. Here we report the first X-ray crystal structure of a reactive Rh nitrenoid, enabled by N elimination from an organic azide ligand within a single-crystal matrix. The resulting high-resolution structure displays metrical parameters consistent with a triplet nitrene complex of Rh. The demonstration of facile access to reactive metal nitrenoids within a crystalline matrix provides a platform for structural characterization of the transient species at the heart of C-H functionalization.
在 C-H 官能化化学中，反应中间体的短暂寿命常常阻止了它们的直接表征。例如，介导 Rh 催化的 C-H 胺化的关键氮宾中间体已经逃避了 40 多年的表征。在没有对这些物种进行结构表征的情况下，方法的开发通常是通过计算来指导的。在这里，我们报告了第一个反应性 Rh 氮宾的 X 射线晶体结构，这是通过在单晶基质中从有机叠氮化物配体中消除 N 来实现的。所得高分辨率结构显示出与 Rh 三重态氮宾复合物一致的度量参数。在晶体基质中轻松获得反应性金属氮宾的证明为在 C-H 官能化的核心处对瞬态物种的结构表征提供了一个平台。
