Directing on-surface polymerization via a substrate-directed molecular template.

Using a template to control the on-surface polymerization process is valuable for building functional molecular nanostructures. Here, the role of the symmetric matching between a halogen-ligand component (H 2 TBrPP) and the substrate for the fabrication of a regular metal-organic structure on Cu(111) and Cu(100) surfaces was studied using scanning tunnelling microscopy (STM). Considering the formation of short-range order polymers on the Au(111) surface via the process of debromination due to the weak directing effect from the substrate to the precursors, a bilayer of ordered assembled structure of H 2 TBrPP/Au(111) has been fabricated and the molecules in the top layer are guided by the first-layer molecules. Owing to the steering effect of the substrate-directed molecular template, the H 2 TBrPP components in the top layer were polymerized into ordered molecular chain arrays along the given direction that is determined by the initial close-packed assembled structure of H 2 TBrPP components during the post-annealing treatment.