Chiral Metal-organic Framework Core-shell Composites Are Used As Research For High Performance Liquid Chromatographic Separation

Metal-organic frameworks（MOF）is a new type of porous materials self-assembled from metal ions/clusters and organic ligands.MOFs have attracted widespread attention due to their diverse topological structures,high specific surface area,uniform and adjustable pore cavities,and modifiable pore surfaces,as well as their potential applications in separation,catalysis,and sensing.However,due to the irregular morphology,non-uniformity,and wide size distribution of MOFs particles,chromatographic columns prepared with pure MOFs have shortcomings such as high column back pressure,low column efficiency,and unsatisfactory peak shape,which seriously hinder their practical application in the field of chromatographic separation.Using chiral MOFs immobilized on the surface of silica microspheres to construct a uniform spherical composite material as a stationary phase is an effective strategy to overcome these problems.In this paper,CMOFs were grown in situ on the surface of Si O₂ microspheres,and a high-performance chiral material was prepared based on it CMOFs@Si O₂ Material and apply this CMOFs@Si O₂ to explore its chiral recognition performance in HPLC as a high performance liquid chromatography stationary phase.The main research content of this article includes the following four chapters:The first chapter is an introduction,which briefly explains the significance of chirality and chiral resolution,the classification of HPLC and its chiral stationary phases,and focuses on the classification of MOFs,CMOFs,and core shell composite materials CMOFs@Si O₂ Application in the field of chromatographic separation.In Chapter 2,a novel CMOFs core-shell composite material[Zn₂（D-Cam）₂（4,4′-bpy）]_n@Si O₂ was prepared by in-situ growth method using aminated silica gel as the core and chiral[Zn₂（D-Cam）₂（4,4′-bpy）]_n as the shell.Chiral core-shell composite material[Zn₂（D-Cam）₂（4,4′-bpy）]_n@Si O₂applied to HPLC separation of enantiomers.Experimental results show that the prepared[Zn₂（D-Cam）₂（4,4′-bpy）]_n@Si O₂ the packed column has good separation performance for 12 racemic compounds and 9positional isomers.In Chapter 3,using carboxylated spherical silica gel as the core,chiral MOFs（[Cu₂（D-cam）₂（dabco）],[Cu₂（D-cam）₂（bipy B）]）were grown on the surface of carboxylated silica gel using a one-pot synthesis method to prepare（[Cu₂（D-cam）₂（dabco）]@Si O₂,[Cu₂（D-cam）₂（bipy B）]@Si O₂）core-shell microspheres as chiral stationary phases for HPLC separation of enantiomers.The effects of different pore sizes of chiral MOFs in two core shell composite materials on enantiomeric separation were investigated.The results showed that the two prepared CMOFs@Si O₂ Packed columns exhibit different chiral recognition abilities,and the pore size of chiral MOFs has different resolution effects on enantiomeric molecules of different molecular sizes.In Chapter 4,chiral compounds were prepared by in situ growth using carboxylated silica gel（Si O₂-COOH）as the core and L-histidine modified MOF MIL-53-NH₂ as the shell.L-his-MIL-53-NH₂@Si O₂ core shell composite material was used as a stationary phase to prepare a HPLC chiral column.The changes in separation performance and reproducibility of packed columns with changes in injection volume and temperature were compared.The chiral column exhibits good separation ability and reproducibility for 14 chiral compounds.