The Investigation Of The Surface Host-guest Chemistry Of C₃-symmetric Carboxylic Acid

In this thesis,using scanning tunneling microscope?STM?as the main research method,a series of host-guest related self-assembled structures are studied on the surface of highly oriented pyrolytic graphite?HOPG?,combined with density functional theory?DFT?to summarize the rules and characteristics,the main research contents are as follows:?1?Explored through STM:the self-assembly structure of H2L molecules in different solvents,and found that H₂L molecules will form different self-assembly structures in different solvents and explore its formation mechanism.The TCDB main molecular grid is used to assist the imaging of depdtt on the HOPG surface,and further explores the photochemical reaction of cis-trans isomerization of DEPDTT molecules after ultraviolet irradiation.These results show that solvents play an important role in the configuration of molecular assembly structure,and the photochemical reactions on the surface provide practical guidance and ideas for the preparation and application of photoelectric molecular devices.?2?Through STM and DFT theoretical calculations,the self-assembly behaviors of two functional organic small molecules TTBTA and TATBA were studied.Both TTBTA and TATBA molecules can self-assemble into a six-membered ring structure through hydrogen bonding interaction,and the guest molecule COR is introduced to construct the three-component co-assembly structure of TTBTA/TATBA/COR.The preferential adsorption of the main grid is explained in terms of thermodynamics and dynamic processes.It is helpful for us to further deepen our understanding of the multi-component host-guest system,and further reveal the rules and principles of selective adsorption of the guest in different host structures.?3?By using the two-dimensional host grid structure formed by the assembly of TCDB molecules as a template,a host-guest system formed by co-assembly of TPPOH-2tris,TPPOH-POM molecules and TCDB was successfully obtained.It was found that the filling of TPPOH-2tris and TPPOH-POM molecules into the TCDB cavity did not cause changes in the structure of the quadrilateral cavity.However,the heteropolyacid portion of the TPPOH-POM molecules contained more metal particles and appeared exceptionally bright.On the other hand,we successfully obtained the structural information of the COF-3 nanosheets at the HOPG/phenyloctane/ethanol interface without damage.The data results are concise and clear without further optimization.