Identification of a peripheral substitution symmetry effect in self-assembled architectures.
Two complementary classes of molecules based on a triphenylene core are synthesized. The two-dimensional (2D) assemblies of these molecules deposited on a highly oriented pyrolytic graphite (HOPG) surface are identified with scanning tunneling microscopy (STM). Structures with large cavities are formed by symmetric molecules, while uniform and closely packed stripe-assembled structures are obtained for asymmetric molecules. X-ray diffraction (XRD) results support the observation of an ordered hexagonal columnar mesophase for symmetric molecules and a rectangular columnar mesophase for asymmetric molecules. The study demonstrates that the substitution symmetry has significant effects on the assembly characteristics of molecular architectures and also on the three-dimensional (3D) macroscopic properties of the molecular materials.
Ma
Xiao-Jing
XJ
National Center for Nanoscience and Technology, Beijing 100080, PR China.
Yang
Yan-Lian
YL
Deng
Ke
K
Zeng
Qing-Dao
QD
Wang
Chen
C
Zhao
Ke-Qing
KQ
Hu
Ping
P
Wang
Bi-Qin
BQ
D002152:Calorimetry, Differential Scanning; D002627:Chemistry, Physical / Q000379:methods*; D002911:Chrysenes / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D050866:Liquid Crystals; D016252:Microscopy, Scanning Tunneling; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014961:X-Ray Diffraction
D002911:Chrysenes; C009590:triphenylene; D006108:Graphite