Chen Shenwei, Cai Zeying, Ou Zengfu, Wang Zhiqiang, Guo Donghui, Zhong Dingyong
School of Physics, Sun Yat-sen University, 510275 Guangzhou, China.
State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China.
Phys Chem Chem Phys. 2021 Oct 6;23(38):22155-22159. doi: 10.1039/d1cp03460j.
Selective C-H bond activation of polycyclic aromatic hydrocarbons is challenging due to the relatively high bond dissociation energy and the existence of multiple equivalent C-H sites. Herein, we report a scanning tunneling microscopy study on the covalent coupling of pentacene molecules on Au(110) surfaces. The missing-row reconstruction of Au(110) surfaces strengthens the molecule-substrate interactions. At elevated temperatures (470-520 K), pentacenes undergo direct aryl-aryl coupling C-H bond activation. Due to the anisotropic feature of the reconstructed Au(110) surface, pentacenes are preferentially oriented parallel or perpendicular, making the linear and T-shaped dimers the predominant products. Based on density functional theory calculations, the aryl C-H bond activation barrier is reduced to 1.42 eV on Au(110)-(1 × 3) reconstructed surfaces, at which the extra row of gold atoms located in the (1 × 3) reconstructed grooves plays a key role.
由于多环芳烃中碳氢键的键解离能相对较高，且存在多个等价的碳氢键位点，因此其选择性碳氢键活化具有挑战性。在此，我们报道了一项关于并五苯分子在Au(110)表面共价偶联的扫描隧道显微镜研究。Au(110)表面的缺行重构增强了分子与底物之间的相互作用。在高温（470 - 520 K）下，并五苯发生直接芳基-芳基偶联——碳氢键活化。由于重构的Au(110)表面具有各向异性特征，并五苯优先平行或垂直排列，使得线性和T形二聚体成为主要产物。基于密度泛函理论计算，在Au(110)-(1×3)重构表面上，芳基碳氢键的活化能垒降低至1.42 eV，位于(1×3)重构凹槽中的额外一排金原子在其中起关键作用。
