Synthesis And Assembly Of Three Urea Derivatives

In this thesis tri-urea receptors have been designed and synthesized for gel and self-assembly. There are four chapters. The first chapter summarizes the development of supra molecular chemistry, literature works in urea receptors self-assembly and recognition, and the aim of this thesis in final. Chapter2-4present details of this study with the main results as the following:1. A long alkyl receptor L is based on the tri-urea scaffold. The ligand can assemble different morphologys in cyclohexane, such as stick-shape, helical fibrous, helical tubular, flower clusters. We research the alkyl chain, concentration, time, temperature and other conditions changing the assemble morphologies. With alkyl chain longing, the morphology is sticks, fibers or flower clusters. With increasing the concentration, the tubes become the flowers;The receptors have been heated and we will get organized morphology; Extension of time and ultrasound can not change the morphology.2. The synthesis tri-urea receptors L and M by three ethoxy are described, and apply it in a gel and self-assmble. The receptor may form a gel in dioxane, mass ratio L:M=2.8:1, concentration of gel30mg/mL in halogenated hydrocarbon (dichloromethane, chloroform,1,2-ichloroethane,1,1,2,2-tetrachloroethane),.the mixed receptor become gel which be freeze-dried in dioxane and the sample is network structure by scanning electronmicroscopy. The atomic force microscopy further demonstrated fiber structure in dilute solution of receptors.3. The tri-urea polymer has been synthesized and it can complex with phosphate by hydrogen bonding and form a new multi-armed polymer. However, we get not the coordination polymers information by size exclusion chromatography (SEC) and matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF-MS). We analysis the reasons:On the one hand the polymer steric is so large that reduce bond strength of tri-urea polymer and phosphate. On the other hand the concentration is too low in the SEM, so affects hydrogen bonds with tri-urea and phosphate.