title: Chiral Self-Assembly of Nonplanar 10,10'-Dibromo-9,9'-bianthryl Molecules on Ag(111).
abstract: We report on the low-temperature scanning tunneling microscopy (STM) measurements of the self-assembly of nonplanar 10,10'-dibromo-9,9'-bianthryl (DBBA) molecules on Ag(111) combined with density functional theory (DFT) calculations. DBBA molecules have two enantiomorphous adsorption configurations, from which more chiral structures can be formed. At a low coverage [0.4 monolayer (ML)], DBBA forms racemic netlike islands consisting of molecular chains along ⟨1 2 3̅⟩Ag. Moreover, the gliding between the molecular chains gives rise to chiral windmill-like patterns in the islands. At 0.8 ML, DBBA forms a racemic row phase and a homochiral hexamer phase. The molecular appearance difference between the two coexisted phases and the DFT calculated molecular adsorption configuration reveal a decrease in the molecular dihedral angle of DBBA, which implies an enhancement in the intermolecular interactions via CH···π and halogen bonds. The transition from a racemic packing mode to a homochiral one suggests that the suitability of steric configurations is dominant in the close-packing mode under enhanced intermolecular interactions.
authors.forename: Yixian
authors.initials: Y
authors.lastname: Shen
authors.forename: Guo
authors.initials: G
authors.lastname: Tian
authors.forename: Han
authors.identifier: 0000-0003-0641-1962
authors.initials: H
authors.lastname: Huang
authors.forename: Yanwei
authors.initials: Y
authors.lastname: He
authors.forename: Qiliang
authors.initials: Q
authors.lastname: Xie
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, P. R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Song
authors.affiliation: College of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, P. R. China.
authors.forename: Yunhao
authors.identifier: 0000-0001-6825-7206
authors.initials: Y
authors.lastname: Lu
authors.forename: Pingshan
authors.identifier: 0000-0002-1988-7604
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Gao