Surface Assisted Reaction under Ultra High Vacuum Conditions

The construction of covalently bonded molecular structures on single crystal metal surfaces has attracted increasing attention because of the synthetic strategies used and their potential application to molecular electronics and optoelectronics. Unlike traditional organic synthesis, surface-assisted reactions have advantages for structural control of the produced polymers, providing detailed understanding of reaction processes, and, most importantly, they produce new materials that cannot be synthesized by traditional means. The types of reactant, the choice of metal surface, and the initial conditions are critical controlling parameters in surface-assisted reactions. Covalent bonds formed in the reaction ensure that the produced structures have higher mechanical and thermodynamic stability compared with self-assembled monolayers (SAMs). Meanwhile, some conjugated polymers are ideal candidates for semiconductors in next-generation carbon-based electronics. In this review, we summarize the surface assisted reactions reported in recent years and analyze the mechanisms involved, comparing them with the corresponding reactions that occur in solution. Finally, we discuss the important role of substrate surface played in the reaction process.