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Ag(111)上化学吸附诱导联苯二聚体的形成
作者:小柯机器人 发布时间:2021/12/31 15:56:32

中科院近代物理研究所朱俊发团队报道了Ag(111)表面化学吸附诱导联苯二聚体的形成。相关研究成果发表在2021年12月29日出版的《美国化学会杂志》。

研究人员报告了一个例子,证明了表面支撑反应和分子吸附构型之间明显的相互依赖关系。2,2′-二溴联苯(DBBP)和2,2′,6,6′-四溴-1,1′-联苯(TBBP)这两个具有两个和四个溴取代基的联苯基分子在Ag(111)表面上表现出完全不同的反应途径,分别导致二苯并[e,l]芘和联苯二聚体的选择性形成。综合低温扫描隧道显微镜、同步辐射光电子能谱和密度泛函理论计算,研究人员揭示了潜在的反应机理。

脱溴后,双自由基联苯可通过表面银原子稳定,而四自由基联苯由于其在Ag(111)上的极端不稳定性而经历自发的分子内环化。DBBP和TBBP之间这种不同的化学吸附诱导前体状态导致进一步退火后的反应路径不同。此外,使用键解析扫描隧道显微镜和扫描隧道光谱,研究人员以原子精度测定了联苯二聚体产物的键长变化,该产物包含4、6和8元环。四元环单元是放射状结构。

附:英文原文

Title: Chemisorption-Induced Formation of Biphenylene Dimer on Ag(111)

Author: Zhiwen Zeng, Dezhou Guo, Tao Wang, Qifan Chen, Adam Matěj, Jianmin Huang, Dong Han, Qian Xu, Aidi Zhao, Pavel Jelínek, Dimas G. de Oteyza, Jean-Sabin McEwen, Junfa Zhu

Issue&Volume: December 29, 2021

Abstract: We report an example that demonstrates the clear interdependence between surface-supported reactions and molecular-adsorption configurations. Two biphenyl-based molecules with two and four bromine substituents, i.e., 2,2′-dibromobiphenyl (DBBP) and 2,2′,6,6′-tetrabromo-1,1′-biphenyl (TBBP), show completely different reaction pathways on a Ag(111) surface, leading to the selective formation of dibenzo[e,l]pyrene and biphenylene dimer, respectively. By combining low-temperature scanning tunneling microscopy, synchrotron radiation photoemission spectroscopy, and density functional theory calculations, we unravel the underlying reaction mechanism. After debromination, a biradical biphenyl can be stabilized by surface Ag adatoms, while a four-radical biphenyl undergoes spontaneous intramolecular annulation due to its extreme instability on Ag(111). Such different chemisorption-induced precursor states between DBBP and TBBP consequently lead to different reaction pathways after further annealing. In addition, using bond-resolving scanning tunneling microscopy and scanning tunneling spectroscopy, we determine with atomic precision the bond-length alternation of the biphenylene dimer product, which contains 4-, 6-, and 8-membered rings. The 4-membered ring units turn out to be radialene structures.

DOI: 10.1021/jacs.1c08284

Source: https://pubs.acs.org/doi/10.1021/jacs.1c08284

 

期刊信息

JACS:《美国化学会志》,创刊于1879年。隶属于美国化学会,最新IF:14.612
官方网址:https://pubs.acs.org/journal/jacsat
投稿链接:https://acsparagonplus.acs.org/psweb/loginForm?code=1000