Preparation And Performance Investigation Of Polydiacetylene For Detecting Chiral Molecules And Metal Ions

Polydiacetylene(PDA)is a highly conjugated polymer with a wide range of uses.Because its unique optical properties are derived from the multiple conjugated double bonds that alternate on the polymer backbone,it has been extensively studied in many fields.The main chain of the polymer undergoes 1,4-polymerization of diacetylene monomers to obtain blue non-fluorescent PDA under 254 nm ultraviolet light.The?-?interaction on the main chain of the conjugate structure is interfered by the external environment.Such as p H,temperature,electrical stress,mechanical stress and ligand-receptor interaction,etc.,with the ability of blue-red colorimetric conversion.When the blue phase PDA is disturbed by external stimuli and undergoes blue-red conversion,it will also emit fluorescence in the red zone.In addition,the rigid conjugated framework of PDA through its unique topological chemical polymerization method,also endows PDA biomaterials with excellent mechanical strength and stability,such as liposomes,micelles and biological scaffolds.The introduction of functional groups into polydiacetylene monomers can develop multifunctional materials.In this paper,polydiacetylene is used as the basic structural unit,and chiral groups and urea groups are designed and introduced,and their applications in chiral recognition and ion recognition as well as temperature sensors have been studied.The research content is as follows:Based on 4-pentynoic acid,a series of symmetrical conjugated diacetylenic compounds were synthesized by introducing chiral amino acid groups to explore their applications in chiral recognition and temperature sensing.Based on 6-heptynol unit,modified the ureido group into a conjugated symmetrical diacetylene,and obtained a series of compounds that respond to ions.Its structure is determined by nuclear magnetic resonance spectrum,ESI mass spectrometry,etc.Through ultraviolet-visible spectroscopy,infrared spectroscopy,fluorescence spectroscopy,proton nuclear magnetic resonance spectroscopy and rheometer to explore the internal reasons for its changes with changes in external conditions,by making them into gels or liposomes.To explore the specific response behavior of chiral molecule recognition and ion recognition,and observe its microscopic morphology by scanning electron microscope.Explored the visual response of Chiral-PDA series(L-Phe-NH-NH₂,L-Val-NH-NH₂,L-Ile-NH-NH₂)liposomes to temperature and the visualization of their gel state for chiral molecules Recognition.By introducing chiral amino acids,a new chiral center is formed.Due to the different forces on different chiral molecules,this series of compounds can specifically recognize chiral molecules,realizing the visual recognition of chiral molecules in the gel state.In the L-Phe-NH-CO-NH-PDA series(L-Phe-NH-CO-NH-C₆,L-Phe-NH-CO-NH-C₁₂,L-Phe-NH-CO-NH-C₁₈),the compound not only shows a temperature response in the liposome state,but also shows a reversible temperature response in the gel state and the solid state,and realized the visual recognition of Pb²⁺in the liposome state and the gel state.