Assembly And Chiral Separation Performance Of MOF Based On L-Phenylalanine

Metal organic framework（MOF）is a kind of crystal coordination compound which is connected by organic ligands and metal ions or ion clusters.It represents a new kind of microporous polymer materials with adjustable physical and chemical properties.In recent years,MOF has become an active research topic for researchers because of its own structure and special properties.MOF has a wide range of applications in many fields,such as gas separation and storage,catalysis of various organic reactions,separation and impurity removal,bioelectrochemistry and so on.It is mainly due to the ultra-high specific surface area and high porosity.If we can reasonably design the structural building unit,it is the birth of a class of novel materials.Organic ligands are a key link in the whole structure and function.If the organic ligands are chiral,the desired chiral porous materials will be synthesized later.The materials provide a micro chiral environment and are widely used in chiral separation,catalysis and others research.Therefore,we intend to construct some chiral building units from L-phenylalanine,m-benzoic acid,2,6-pyridinedipyridine carboxylic acid.Chiral metal organic frameworks with different pore sizes were fabricated by simple hydrothermal reaction and doping of electrodeless metal ions.The details are as follows:（1）In this chapter,L-phenylalanine,a common chiral starting material in nature,was used to synthesize C₃ symmetric chiral ligand H₃L with m-tribenzoic acid,and a novel material Zn MOF（material 1）with 3D structure was obtained by one pot reaction with metal ion Zn²⁺.The material 1 is located in the space group Pi2₁3,which indicates that the crystal is an orthorhombic cubic crystal form and presents a Cubic model.Through the dye adsorption experiment of material 1,it is found that the material can adsorb basic fuchsin molecules,indicating that the material has certain chiral pores and the adsorption capacity.Using material 1 as the chiral separation extractant,the selective separation performance of the small molecule pharmaceutical intermediate epoxy compound enantiomers was explored,and the ee value of the chiral separation of the material 1reached 99%from the experimental results.（2）This chapter still uses natural cheap L-phenylalanine as a single chiral source and isophthalic acid and M-dipicolinic acid to synthesize two chiral C₂ symmetric V-type ligands（H₂L₂,H₂L₃）,two ligands Two crystals were obtained by reacting with zinc salt through hydrothermal solvent and named material 2 and material 3.Through crystal structure analysis,the coordination modes of the two chiral MOF materials are the same,both are three-dimensional structures,and the space group is both P322₁.The comparison of the two structures shows that the introduction of the designed V-type ligand H₂L₃ into the pyridine atom does not affect the coordination of its metal ions,which proves that the chiral ligand has a certain universality.In this experiment,material 2 is used as a representative to explore the coordination method of its structure,and the dye adsorption experiment verifies that the chiral material 2 has a certain chiral cavity and adsorption capacity.