Guidance on surface cyclization reactions through coordination structures

Metal coordination structures, formed through interactions between metal atoms and active functional groups, are crucial in determining the reaction pathway and its products. This study examines 2,3-dibromo-6,7-dicyanonaphthalene (DDN), which contains cyano and halogen groups, deposited on Au(111) and Ag(111) surfaces, using scanning tunneling microscopy at room temperature. The reason for the formation of various cyclization products on the Au(111) surface is that the bromine of DDN and the cyano group have overlapping reaction temperature ranges. This overlap leads to the coexistence of C-C coupling products from the debromination sites and cyclization products from the cyano groups. In contrast, on the Ag(111) surface, the final cyclization reaction produces a single type of polymer directly induced by the metal-coordinated structures. The synergistic effects between coordination structures and the activation temperatures of molecular reaction groups are crucial factors in regulating polymerization reactions.