The Study Of Synthesis,Assembly And Stimuli-Responsive Behaviors Based On Azobezene Containing π-Conjugated Molecules

Supramolecular self-assembled?-conjugated materials are promising candidates for a variety of potential applications,such as optoelectronics and supramolecular nanomaterials.The control of weak noncovalent interactions,such asπ-πstacking,hydrogen bonding,electrostatic interactions,van der Waals forces,etc.,at molecular level,is critical in regulating the self-assembled architectures and optical properties.Aimed at developing novel functionalizedπ-conjugated systems,this thesis reported the molecular design,synthesis and property investigation of a series of azobenzene basedπ-conjugated systems.The results can be summarized as follows:1.We have designed and synthesized two azobenzene-based coil-rod-coil molecules（Azo-2 and Azo-3）.The incorporation of azobenzene into the rigid core not only provided strongπ-πinteraction favored for anisotropic assembly,but also produced a new kind of photo-responsive liquid crystal.It was found that they could form stable organogels toward various organic solvents through a synergic effect ofπ-πstacking,intermolecular hydrogen bonding,and van der Waals forces.The photo-switching properties of Azo-2 and Azo-3 were studied both in solution and liquid crystal states,demonstrating their fast responsiveness to UV light.These prominent features make them excellent stimuli-responsive multifunctional materials with promising potential applications in optical memory devices,optical displays,and optical switches.2.We have designed and synthesized two azobenzene-based molecules（TBA₂-Azo and AzoCOONa）and one tetraphenylmethane-based molecule（TPM-4Cl）.Mixing aqueous solutions of TBA₂-Azo（AzoCOONa）and TPM-4Cl resulted in the formation of needle-like crystals under the joint effect of hydrogen bonding and electrostatic interaction.FT-IR spectroscopy and ¹H NMR revealed that the formation of the frameworks.Thermal gravimetric analysis（TGA）suggested the thermal stability of the crystals.Furthermore,the frameworks can be controllably disassembled and reassembled in response to acid/base triggers which suggested that this new class of materials may have applications in the field of controlled release and guest storage.