Dehydrofluorination as a Residue-Free Selective Route to C–C Bond Formation at Metal Surfaces
Dehydrofluorination as a Residue-Free Selective Route to C–C Bond Formation at Metal Surfaces
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DOI：
10.1021/acs.jpcc.2c00712
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
J. Viereck;Yang Zhang;E. Galoppini;R. Bartynski;S. Rangan
中科院分区：
文献类型：
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作者：
J. Viereck;Yang Zhang;E. Galoppini;R. Bartynski;S. Rangan
由于缺乏对反应位点的控制以及前体之间形成共价键的化学途径有限，通过合理的合成设计引导分子前体的共价表面聚合受到损害，导致对结果和寄生表面反应副产物的控制有限。在这里，我们研究了最近报道的 C-C 键形成化学途径的机制：金属表面的脱氟化氢。我们证明，这种化学路线，特别是 C-H/F-C 对，有利于一步消除气相中的 HF，从而消除金属表面的反应副产物。与脱卤不同，我们发现脱氟化氢反应的显着选择性使得这种 C-C 键形成策略具有化学选择性，并且如果与正确设计的分子前体一起使用，也具有潜在的区域选择性。此外，我们证明金属基材的催化作用可用于引导反应途径并在脱氟化氢和脱氢反应之间进行选择。由于这些原因，金属表面上很大程度上尚未探索的脱氟化氢反应可能成为表面合成的有价值的工具。
Directing covalent on-surface polymerization of molecular precursors through rational synthetic design has been impaired by the lack of control over reaction sites and by limited chemical routes to covalent bond formation between precursors, resulting in limited control of the outcomes and parasitic surface reaction byproducts. Here we investigate the mechanism of a recently reported chemical route to C–C bond formation: dehydrofluorination on metal surfaces. We demonstrate that this chemical route, involving specifically C–H/F–C pairs, favors the elimination of HF in the gas phase as a single step, therefore eliminating reaction byproducts at the surface of metals. Unlike dehalogenation, we find that the remarkable selectivity of the dehydrofluorination reaction renders this C–C bond formation strategy chemoselective as well as potentially regioselective, if employed with a properly designed molecular precursor. Additionally, we demonstrate that the catalytic role of the metal substrate can be used to steer reaction pathways and select between dehydrofluorination and dehydrogenation reaction. For these reasons, the dehydrofluorination reaction, largely unexplored on metal surfaces, could become a valuable tool for on-surface synthesis.