Steering On-Surface Reactions by a Self-Assembly Approach.

4,4'-Bis(2,6-difluoropyridin-4-yl)-1,1':4',1''-terphenyl (BDFPTP) molecules underwent dehydrocyclization and covalent coupling reactions on Au(111) according to scanning tunneling microscopy (STM) measurements and density functional theory (DFT) calculations. Self-assembly of the reactants in well-defined molecular domains prior to reaction could greatly enhance the regioselectivity of the dehydrocyclization reaction and suppress defluorinated coupling, demonstrating that self-assembly can efficiently steer on-surface reactions. Such a strategy could be of great importance in surface chemistry and widely applied to control on-surface reactions.