Lin Tao, Zhang Liding, Björk Jonas, Chen Zhi, Ruben Mario, Barth Johannes V, Klappenberger Florian
Physik-Department E20, Technische Universität München, James-Franck-Str., 85748, Garching, Germany.
Department of Physics, Chemistry, and Biology (IFM), Linköping University, 58183, Linköping, Sweden.
Chemistry. 2017 Nov 7;23(62):15588-15593. doi: 10.1002/chem.201701735. Epub 2017 Oct 18.
Surface-templated covalent coupling of organic precursors currently emerges as a promising route to the atom-precise fabrication of low-dimensional carbon materials. Here, we investigate the adsorption and the coupling reactions of 4,4''-diethynyl-1,1':4',1''-terphenyl on Au(110) under ultra-high vacuum conditions by using scanning tunneling microscopy combined with density functional theory and kinetic Monte Carlo calculations. Temperature treatment induces both 1,2,4-asymmetric cyclotrimerization and homocoupling, resulting in various reaction products, including a previously unreported, surface-templated H-shaped pentamer. Our analysis of the temperature-dependent relative product abundances unravels that 1,2,4-trimerization and homocoupling proceed via identical intermediate species with the final products depending on the competition of coupling to a third monomer versus dehydrogenation. Our study sheds light on the control of coupling reactions by corrugated surfaces and annealing protocols.
目前，有机前驱体的表面模板共价偶联作为一种有前景的方法，可用于低维碳材料的原子精确制造。在此，我们利用扫描隧道显微镜结合密度泛函理论和动力学蒙特卡罗计算，研究了超高真空条件下4,4''-二乙炔基-1,1':4',1''-三联苯在Au(110)上的吸附和偶联反应。温度处理引发了1,2,4-不对称环三聚反应和均偶联反应，产生了各种反应产物，包括一种以前未报道的、表面模板化的H形五聚体。我们对温度依赖性相对产物丰度的分析表明，1,2,4-三聚反应和均偶联反应通过相同的中间物种进行，最终产物取决于与第三个单体偶联与脱氢的竞争。我们的研究揭示了通过波纹表面和退火协议对偶联反应的控制。
