Construction Of Functional MOFs And Their Composites Based On Triethylenediamine-modified 1,3,5-tris(4-carboxyphenyl)benzene

Metal-organic frameworks(MOFs),also known as porous coordination polymers(PCPs),are porous crystalline materials with two-dimensional or three-dimensional infinite structures formed by the coordination of metal ions or clusters to multidentate organic ligands.Over the past few years,MOFs have become one of the most popular research areas in chemistry and materials science due to their large specific surface area,tunable pore size,and structural diversity.These properties make them promising applications in gas adsorption and separation storage,heterogeneous catalysis,sensing,luminescence,proton conduction,and drug delivery.This work is based on 1,3,5-(4-carboxyphenyl)benzene ligands(BTB-DABCO)modified with basic functional groups triethylenediamine(DABCO)with metal zirconium and copper,respectively,under solvothermal conditions.A functional metal-organic nanosheet core-shell material(Si O₂@MOL-DABCO)and a cationic metal-organic framework(MOF-DABCO)were obtained by coordination assembly.The structures of these two materials were investigated by a series of tests.Characterization and verification,and in-depth exploration of the activity of Si O₂@MOL-DABCO in the tandem acid-base active site catalytic reaction of acetal hydrolysis and Knoevenagel condensation.In addition,the cationic framework of MOF-DABCO in iodine adsorption and desorption was also explored.application.The full text is divided into the following four chapters.Chapter 1:Introduction,firstly introduces the applications and challenges of 3D metal-organic framework material MOFs and 2D metal-organic nanosheets(MOLs)layer materials in the field of catalysis,and the hybrid materials formed by the composite of MOFs materials and silicon-based supports The characteristics,research progress,and applications and challenges of these materials in the field of catalysis.Secondly,the development of solid-phase adsorbents in the field of iodine adsorption and separation and the outstanding performance of emerging MOFs materials in iodine adsorption are introduced.Finally,the design idea and significance of the research topic in this paper are briefly described.Chapter 2:In situ addition of surface carboxyl modified silica microspheres during the synthesis of metal-organic nanosheets,the nanosheets were evenly anchored on the surface of silica microspheres,and the core-shell composite Si O₂@MOL-DABCO was obtained.Among them,the uncoordinated unsaturated sites in the Zr₆ metal cluster have Lewis acidity,while the nitrogen atom in DABCO has Lewis basicity.Due to the orderly arrangement of metal-organic framework materials,these two active sites are independent of each other and are not affected by each other.Interfering with each other,Si O₂@MOL-DABCO has acid and alkali dual active sites,which are fully exposed on the surface of nanosheets.Based on this,in this chapter,the core-shell material Si O₂@MOL-DABCO catalyzed the tandem reaction of acetal dealkylation-Crawinger tandem preparation of malononitrile under mild conditions,and the final product can be obtained in high yield.Chapter 3:A cationic three-dimensional porous metal-organic framework(MOF-DABCO)was obtained by the coordination combination of BTB-DABCO and copper nitrate under solvothermal conditions.Its structure was characterized by single crystal/powder X-ray diffraction,infrared and other means.The cationic coordination polymer has high iodine storage capacity in solution,and can be recycled for many times during the process of iodine adsorption,storage and release.The fourth chapter summarizes the progress and significance of the research topic of this paper.