Donostia International Physics Center , E-20018 San Sebastián, Spain.
Ikerbasque, Basque Foundation for Science , E-48011 Bilbao, Spain.
J Am Chem Soc. 2016 Aug 31;138(34):10963-7. doi: 10.1021/jacs.6b05203. Epub 2016 Aug 18.
We investigate the thermally induced cyclization of 1,2-bis(2-phenylethynyl)benzene on Au(111) using scanning tunneling microscopy and computer simulations. Cyclization of sterically hindered enediynes is known to proceed via two competing mechanisms in solution: a classic C(1)-C(6) (Bergman) or a C(1)-C(5) cyclization pathway. On Au(111), we find that the C(1)-C(5) cyclization is suppressed and that the C(1)-C(6) cyclization yields a highly strained bicyclic olefin whose surface chemistry was hitherto unknown. The C(1)-C(6) product self-assembles into discrete noncovalently bound dimers on the surface. The reaction mechanism and driving forces behind noncovalent association are discussed in light of density functional theory calculations.
我们使用扫描隧道显微镜和计算机模拟研究了 1,2-双（2-苯乙炔基）苯在 Au(111)上的热诱导环化。在溶液中，空间位阻烯炔的环化已知通过两种竞争机制进行：经典的 C(1)-C(6)（伯格曼）或 C(1)-C(5)环化途径。在 Au(111)上，我们发现 C(1)-C(5)环化受到抑制，而 C(1)-C(6)环化生成一种高度应变的双环烯烃，其表面化学性质迄今未知。C(1)-C(6)产物在表面上自组装成离散的非共价键合二聚体。根据密度泛函理论计算，讨论了非共价缔合的反应机制和驱动力。
