Synthesis of a copper-supported triplet nitrene complex pertinent to copper-catalyzed amination
Synthesis of a copper-supported triplet nitrene complex pertinent to copper-catalyzed amination
复制标题
DOI：
10.1126/science.aax4423
复制
发表时间：
2019-09-13
期刊：
影响因子：
56.9
通讯作者：
Betley, Theodore A.
中科院分区：
文献类型：
--
作者：
Carsch, Kurtis M.;DiMucci, Ida M.;Betley, Theodore A.
末端铜氮烯配合物激发了人们对其基本键合结构及其在催化氮烯转移反应中的假定中介作用的兴趣。在这里，我们报道芳基叠氮化物与带有空间位阻二吡啉配体的铜（I）二氮配合物反应，生成具有近线性、短铜氮烯键的末端铜氮宾配合物[1.745（2）至1.759（2）埃]。 X射线吸收光谱和量子化学计算揭示了主要与铜(I)结合的三线态氮烯加合物，而不是铜(II)或铜(III)分配，表明不存在铜-氮多重键特征。采用缺电子芳基叠氮化物使铜氮烯物种能够进行烷烃胺化和烯烃氮丙啶化，进一步证明了该物种在所提出的氮宾转移机制中的中间作用。
Terminal copper-nitrenoid complexes have inspired interest in their fundamental bonding structures as well as their putative intermediacy in catalytic nitrene-transfer reactions. Here, we report that aryl azides react with a copper(I) dinitrogen complex bearing a sterically encumbered dipyrrin ligand to produce terminal copper nitrene complexes with near-linear, short copper-nitrenoid bonds [1.745(2) to 1.759(2) angstroms]. X-ray absorption spectroscopy and quantum chemistry calculations reveal a predominantly triplet nitrene adduct bound to copper(I), as opposed to copper(II) or copper(III) assignments, indicating the absence of a copper-nitrogen multiple-bond character. Employing electron-deficient aryl azides renders the copper nitrene species competent for alkane amination and alkene aziridination, lending further credence to the intermediacy of this species in proposed nitrene-transfer mechanisms.