Datensatz

Zusammenfassung

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 C¹–C⁶ or a C¹–C⁵ cyclization pathway. On Au(111) we find that the C¹–C⁵ cyclization is suppressed and that the C¹–C⁶ cyclization yields a highly strained bicyclic olefin whose surface chemistry was hitherto unknown. The C¹–C⁶ product self-assembles into discrete non-covalently bound dimers on the surface. The reaction mechanism and driving forces behind non-covalent association are discussed in light of density functional theory calculations.