title: Steering on-surface polymerization with metal-directed template.
abstract: On-surface polymerization represents a novel bottom-up approach for producing macromolecular structures. To date, however, most of the structures formed using this method exhibit a broad size distribution and are disorderly adsorbed on the surface. Here we demonstrate a strategy of using metal-directed template to control the on-surface polymerization process. We chose a bifunctional compound which contains pyridyl and bromine end groups as the precursor. Linear template afforded by pyridyl-Cu-pyridyl coordination effectively promoted Ullmann coupling of the monomers on a Au(111) surface. Taking advantage of efficient topochemical enhancement owing to the conformation flexibility of the Cu-pyridyl bonds, macromolecular porphyrin structures that exhibit a narrow size distribution were synthesized. We used scanning tunneling microscopy and kinetic Monte Carlo simulation to gain insights into the metal-directed polymerization at the single molecule level. The results reveal that the polymerization process profited from the rich chemistry of Cu which catalyzed the C-C bond formation, controlled the size of the macromolecular products, and organized the macromolecules in a highly ordered manner on the surface.
authors: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors: Tao
authors: T
authors: Lin
authors: Xue Song
authors: XS
authors: Shang
authors: Jinne
authors: J
authors: Adisoejoso
authors: Pei Nian
authors: PN
authors: Liu
authors: Nian
authors: N
authors: Lin
mesh_terms: D003300:Copper / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D058105:Polymerization; D011725:Pyridines / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D009942:Organometallic Compounds; D011725:Pyridines; D003300:Copper