Synthesis Of Bis(Triurea) Receptor And Study On Its Self-assembly Properties

Supramolecular self-assembly shows very unique advantages in the fields of biological simulation and construction of functional materials.So far,chemists have developed a large number of novel and unique supramolecular assemblies driven by metal coordination.External stimuli?such as p H,light,temperature,concentration,solvents,guest molecules,etc.?could be used to induce the interconversion between different supramolecular self-assemblies for efficient construction of more topological structures.Anion-coordination-driven self-assembly is less developed compared with metal-coordination-driven assembly.In this thesis,a bis?triurea?ligand L was designed and synthesized.It can coordinate with phosphate anion to form a A₆L₆type hexagonal structure.Another A₄L₄type structure was also obtained through solvent regulation and the interconversion between these two structures could be performed by changing the volume ratio of solvents.The host-guest properties have also been studied subsequently.In addition,the bis?triurea?ligand L could also coordinate with sulfate anion to generate a simpler A₂L₁configuration.And the identification and detection of specific anions can be achieved by functionalization of the original ligand with a terminal chiral group,using the change of CD and fluorescence signals with addition of different anions.It is of great significance to study the topological structures and properties of anionic assemblies.The full text is divided into three chapters,which mainly include the following:The first chapter is introduction,which focuses on the development of supramolecular chemistry,the constitution of supramolecular self-assembly,the research progress of metal coordination assemblies and urea functionalized anionic receptors and their assemblies,as well as the motivation and research significance of the selected projects.The second chapter describe the design of the project,synthesis of the ligands,phosphate anion driven assembly and solvent regulated structural interconversion.Based on our previous studies of the ortho-phenylene bridged oligourea ligands,a bis?triurea?ligand L was designed and synthesized,which could coordinate with phosphate ion to form a A₆L₆type hexagonal structure.At the same time,another A₄L₄type grid-like structure was obtained by changing the volume ration of used solvents.The formation of these two structures was confirmed by single crystal structures,mass spectrometry and nuclear magnetic resonance.The transformation of these two structures can be easily realized by solvent regulation.Nuclear magnetic resonance,UV-vis spectroscopy and fluorescence spectroscopy indicate that the two structures show interaction with guest methylene blue.The third chapter mainly studies the self-assembly of bis?triurea?ligand L and sulfate ion,as well as the anion recognition abilities of chiral bis?triurea?ligand L^S/R.In the second chapter,we designed and synthesized a nitro-terminated bis?triurea?ligand L which could coordinate with phosphate ion to form two topological structures of A₆L₆hexagon and A₄L₄square by solvent regulation.In order to achieve versatile applications,the bis?triurea?ligand L was further modified with chiral groups to obtain L^S/R.Ligand L^S/Rcould interact with a variety of anions,including CO₃^2-,HCO₃^-,HPO₄^2-,PO₄^3-,SO₄^2-.Among all these anions,PO₄^3-,HPO₄^2-and SO₄^2-cause more obvious changes of fluorescence and chiral signals.Therefore,ligand L^S/Rshows potential application in identification of specific anions.