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 (Bergman) 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 noncovalently bound dimers on the surface. The reaction mechanism and driving forces behind noncovalent association are discussed in light of density functional theory calculations.
ASJC Scopus subject areas
- Colloid and Surface Chemistry