The Study Of Supermolecular Self-assembly Based On Oligophenyl Structures

In the study of molecular science,the applications of supramolecular self-assembled materials are attracting widespread attentions.Functional supramolecular nanostructures with orderly and controllable arrangements have been developed based on low-molecular-weight modules,via supramolecular self-assembly induced by weak intermolecular interactions,including hydrogen bondings,?-? interactions,van der Waals forces,hydrophilic/hydrophobic effects,and electrostatic interactions.In this thesis,a series of work on supramolecular self-assembly research based on oligophenyl structure can be summarized as follows:1.A series of dumbbell-shaped molecules with a p-quaterphenylene(QP)core,and ester-linked counterparts(QP-e)were synthesized.QP showed excellent gelation ability: they tended to form gels in many organic solvents.It was proved that the gelation rate could be controlled by ?-? stacking between p-quaterphenylene segments,and amide bond has also played a key role in the process of gelation(e.g.QP-e was unable to form gel without hydrogen bonds).After the formation of organogels,aggregation-induced fluorescence emission was discovered.Moreover,the supramolecular aggregates based on p-quaterphenylenes as the new AIEgens possess potential applications in the fabrication of explosive sensors.2.Dumbbell-shaped molecules cored with a p-terphenylene core and linked with thioamide groups were synthesized,and their self-assembling properties were investigated.In our previous work,we found that para-terphenylen-1,4”-ylenebis(dodecanamide)(TB)could be dissolved upon heating in many organic solvents.After cooling to room temperature,it was found to self-assemble into nanotubes.In order to adjust the aggregation behaviours,as well as the self-assembly morphology,herein,the amide groups were replaced with thioamide groups,which possess many beneficial properties such as the large dipole moment and strong hydrogen-bond donating capacity,etc.Through a series of measurements such as Scanning electron microscopy,temperature-dependent UV-Vis absorption spectroscopy and CD spectroscopy,the target molecules were proved to form short one-dimensional nanofibers.This work provides a strategy to design novel assembly segments with thioamide unit.