Zhang Ran, Xia Bowen, Xu Hu, Lin Nian
Department of Physics, The Hong Kong University of Science and Technology, Hong Kong SAR, China.
Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
Angew Chem Int Ed Engl. 2019 Nov 11;58(46):16485-16489. doi: 10.1002/anie.201909278. Epub 2019 Oct 4.
We investigate the on-surface [2+2] cycloaddition reaction of 2,3,6,7,10,11-hexabromotriphenylene (HBTP) on Ag(111), Cu(111), Au(111), and Cu-dosed Au(111) surfaces using STM and DFT simulation focusing on the organometallic intermediates. The fully debrominated HBTP molecules form an organo-silver framework on Ag(111) and an organo-copper framework on Cu(111), both incorporating multinuclear metal adatom clusters. The organo-silver framework is converted into porous covalent networks via [2+2] cycloaddition above 240 °C. In contrast, the organo-copper framework is very stable and does not undergo [2+2] cycloaddition even at 300 °C. On Au(111), no organo-gold intermediate of [2+2] cycloaddition is observed. After loading Cu onto Au(111), the partially debrominated HBTP molecules bind to Cu adatom dimers to form multinuclear organo-copper complexes at 100 °C which undergo [2+2] cycloaddition at 140 °C. This study shows that the choice of surface can direct the reaction pathway.
我们使用扫描隧道显微镜（STM）和密度泛函理论（DFT）模拟，聚焦于有机金属中间体，研究了2,3,6,7,10,11-六溴三亚苯（HBTP）在Ag(111)、Cu(111)、Au(111)和铜掺杂的Au(111)表面上的表面[2+2]环加成反应。完全脱溴的HBTP分子在Ag(111)上形成有机银框架，在Cu(111)上形成有机铜框架，两者都包含多核金属吸附原子簇。有机银框架在240°C以上通过[2+2]环加成转化为多孔共价网络。相比之下，有机铜框架非常稳定，即使在300°C也不发生[2+2]环加成。在Au(111)上，未观察到[2+2]环加成的有机金中间体。在Au(111)上负载铜后，部分脱溴的HBTP分子在100°C时与铜吸附原子二聚体结合形成多核有机铜配合物，并在140°C时发生[2+2]环加成。这项研究表明，表面的选择可以引导反应途径。
