Deciphering Reaction Network for the Switchable Production of Tetrahydroquinoline or Quinoline with MOF-Supported Pd Tandem Catalysts
Deciphering Reaction Network for the Switchable Production of Tetrahydroquinoline or Quinoline with MOF-Supported Pd Tandem Catalysts
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破译 MOF 负载 Pd 串联催化剂可切换生产四氢喹啉或喹啉的反应网络
DOI：
10.1021/acscatal.0c00899
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发表时间：
2020
期刊：
影响因子：
12.9
通讯作者：
Wenyu Huang
中科院分区：
文献类型：
--
作者：
Long Qi;Jingwen Chen;Biying Zhang;Renfeng Nie;Zhiyuan Qi;Takeshi Kobayashi;Zongbi Bao;Qiwei Yang;Qilong Ren;Qi Sun;Zhiguo Zhang;Wenyu Huang
多相串联催化体系的机理研究对于理解和提高催化剂的活性和选择性至关重要，但仍然具有挑战性。在这里，我们表明，一个多步反应的彻底的机理研究可以指导我们可控的选择性合成苯基四氢喹啉或苯基喹啉与容易获得的前体。一锅法生产可以实现，催化的一个明确的，双功能的金属有机骨架负载的钯纳米粒子，只有水作为副产物。我们的机制研究确定了六个瞬态中间体和十个转换步骤，从操作魔角旋转核磁共振研究下27.6巴H2。特别是反应中间体2-苯基-3，4-二氢喹啉不能用常规色谱技术观察到，但发现在操作条件下达到0.11 mol L-1的最大浓度。最可能的反应网络进一步推导的基础上的反应物种的动力学信息，从bothoperandoandex原位反应研究。对复杂反应网络的深刻理解使得能够通过添加均相助催化剂来对关键中间体2-苯基-3，4-二氢喹啉的转化进行动力学控制，从而能够根据需要选择性地生产四氢喹啉或喹啉。在这项工作中所展示的方法开辟了新的途径，有效地调节反应与复杂的网络，以实现所需的选择性。
A mechanistic study of heterogeneous tandem catalytic systems is crucial for understanding and improving catalyst activity and selectivity but remains challenging. Here, we demonstrate that a thorough mechanistic study of a multistep reaction can guide us to the controllable selective synthesis of phenyltetrahydroquinoline or phenylquinoline with easily accessible precursors. The one-pot production can be achieved, catalyzed by a well-defined, bifunctional metal–organic framework-supported Pd nanoparticles, with only water as the side product. Our mechanistic study identifies six transient intermediates and ten transformation steps from the operando magic angle spinning nuclear magnetic resonance study under 27.6 bar H2. In particular, reactive intermediate 2-phenyl-3,4-dihydroquinoline cannot be observed with conventional chromatographic techniques but is found to reach the maximal concentration of 0.11 mol L–1under theoperandocondition. The most probable reaction network is further deduced based on the kinetic information of reaction species, obtained from bothoperandoandex situreaction studies. This deep understanding of the complex reaction network enables the kinetic control of the conversions of key intermediate, 2-phenyl-3,4-dihydroquinoline, with the addition of a homogeneous co-catalyst, allowing the selective production of tetrahydroquinoline or quinoline on demand. The demonstrated methods in this work open up new avenues toward efficient modulation of reactions with a complex network to achieve desired selectivities.