1.CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience,National Center for Nanoscience and Technology (NCNST),Beijing,China;2.Jiangxi College of Applied Technology,Ganzhou,China;3.Engineering Research Center of Nano-Geo Materials of Ministry of Education,China University of Geosciences,Wuhan,China
Abstract:
The two-dimensional self-assembly behaviors of tetraphenylethylene (TPE) molecules are significant for further applications, but reports are rare. The self-assembled structures of two C2-symmetry TPE derivatives (H4TCPE and H4ETTC) possessing propeller structures and their stimulus responses to the addition of vinylpyridine derivatives were thoroughly studied with the assistance of scanning tunneling microscopy (STM) technique in combination with density functional theory (DFT) calculations. Although their chemical structures were similar, the H4TCPE and H4ETTC molecules self-assembled into closely packed lamellar and quadrilateral structures, respectively, at the 1-heptanoic acid/HOPG interface. After the addition of pyridine derivatives (DPE, PEBP-C4, and PEBP-C8), H4TCPE and H4ETTC showed different responsiveness resulting in different co-assembly structures. The results indicated that the structures of pyridine derivatives—including backbones and substituents—affected the intermolecular interactions of both H4TCPE/pyridine and H4ETTC/pyridine systems. The modification of the self-assembly behaviors of propeller-shaped H4TCPE and H4ETTC would contribute to the construction of more complex multilevel nanostructures.
