Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Corrensstrasse 40, 48149 Münster, Germany.
Institute for Solid State Theory and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Str. 10, 48149 Münster, Germany.
J Am Chem Soc. 2017 Jul 12;139(27):9144-9147. doi: 10.1021/jacs.7b05112. Epub 2017 Jun 28.
We report the N-heterocyclic carbene (NHC)-induced activation of an otherwise unreactive Pd/AlO catalyst. Surface analysis techniques demonstrate the NHC being coordinated to the palladium particles and affecting their electronic properties. Ab initio calculations provide further insight into the electronic effect of the coordination with the NHC injecting electron density into the metal nanocluster thus lowering the barrier for bromobenzene activation. By this NHC modification, the catalyst could be successfully applied in the Buchwald-Hartwig amination of aryl chlorides, bromides, and iodides. Various heterogeneity tests could additionally show that the reaction proceeds via a heterogeneous active species.
我们报告了 N-杂环卡宾（NHC）对原本不活跃的 Pd/AlO 催化剂的激活作用。表面分析技术表明，NHC 与钯颗粒配位，并影响其电子性质。从头算计算进一步深入了解了 NHC 配位对电子的影响，将电子密度注入金属纳米簇中，从而降低了溴苯活化的势垒。通过这种 NHC 修饰，该催化剂可成功应用于芳基氯、溴和碘化物的 Buchwald-Hartwig 胺化反应。各种非均相测试还可以表明，反应通过非均相活性物种进行。
