Conjugated Molecular Assembly Structure Regulated By The Interaction Between Metal And Organic Molecules

Self-assembly structures of 2,2':6',2''-terpyridine-4'-carboxylic acid(C₁₆H₁₁N₃O₂;Y_N)molecules and 3,5-diphenylbenzoic acid(C₁₉H₁₄O₂;Y_C)molecules on Ag?110?surface have been investigated by scanning tunneling microscopy.The Y_C molecules form two different well-organized structures due to the?–?stacking and dipole-dipole interactions.When three C atoms of Y_C molecules are replaced by three N atoms to form Y_N molecules,the main driving force to form the assembled structures of Y_N molecule is changed to metal-organic coordination bond and hydrogen bond.The dramatic changes of the main driving force between Y_C/Ag?110?and Y_N/Ag?110?system demonstrate that the N atoms in the groups are helpful to form metal-organic coordination bond and hydrogen bond.These findings further reveal that the optimization design of organic molecules could vary the main driving force and induce the metal-organic coordination bond to control the molecular self-assembly structures.2,7-Dibromotriphenylene?DBTP?molecules form polymers through C-C covalent bonds on both Au?111?and Au?110?surfaces.The DBTP molecules tend to randomly physisorb on Au?111?surface with flat-lying configuration.In contrast,the DBTP molecules are physically adsorbed on the trench of reconstructed Au?110?substrate.With the increase of the annealing temperature,the bottom C-H bonds are broken via dehydrogenation process with the assistant of reconstructed Au?110?substrate,as a consequence,these molecules bridge the Au atoms along the[1-10]orientation of the Au?110?substrate to forms four Au–C bonds.Meanwhile,the polymer formed by DBTP converts to chemisorb with up-right standing configuration from physisorbing with flat-lying configuration.The final polymer chains are highly oriented along the[1-10]direction of the Au?110?substrate.These findings suggest that the adsorption configuration like the conversion of physisoption into chemisorption in the annealing process can be tuned by choosing different substrates to control the molecular interaction with the substrate and induce the metal-organic bond and to get the highly oriented polymer.