Design, Syntheses And Properties Of Metal-Organic Frameworks Based On Multifunctional Organic Ligands

Metal-organic frameworks (MOFs) also known as porous coordination polymers (PCPs) are a new emerging class of porous materials. Due to its many advantages such as controlled pore volume and pore size and high specific surface area, there are good prospects for development in hydrogen storage, catalytic materials, optical materials, etc.This paper uses transition metal ions and main group metal ions with multicarboxylate acid under hydrothermal or solvothermal reaction conditions to. build 20 novel coordination polymers from one-dimensional to three-dimensional structure, and their crystal structures and properties were tested and analyzed. Furthermore, the gas adsorption and dye adsorption were tested for some coordination polymers. The thesis is divided into four chapters:In the first chapter, the concept of the metal organic frameworks, research status and influence factors of coordination polymers as well as the design proposal of this paper, are briefly introduced.The second chapter describes a series of coordination polymers (Zn, Mn) based on H3L1. The zinc MOFs (compounds 1-5) have been synthesized with the participation of ancillary pyridine or bipyridine ligands by hydrothermal method. Their fluorescent properties and the reasons for the change in fluorescence were studied and discussed. By adjusting the ratio of the solvents, three polynuclear manganese cluster coordination polymers (compounds 7-9)were obtained. It showed that the type and the proportion of the solvent influence a multinuclear manganese cluster, thereby affecting the crystal structure.The third chapter introduces the Indium ions with H3L1 to build coordination polymers(compounds 10-12) by adjusting the ratio of solvent. The gas adsorption and fluorescence dye adsorption were tested. Compound 11 has potential applications in selectivity adsorption and separation CO2/N2 as well as fluorescent dyes.The fourth chapter describes a series of coordination polymers based on H3L2 and H3L3. For H3L2, by adjusting the metal-ligand ratio and varying the metal ion species, the single crystal of H3L2 and coordination polymers (compounds 13-17) were obtained. For H3L3, by hydrothermal method, three coordination polymers (compounds 18-20) were obtained. They are virtually isostructural compounds. The outstanding structural feature is that the amide bond involved in the coordination with metal ions. Although examples of the amide bond involved in the coordination with metal ions have been well documented, such kind of exception coordination mode for the acylamide ligand is the first one in coordination polymers composed by polycarboxylic acid ligand modified by amide bond. The syntheses, structures, thermal stabilities, powder X-ray diffractions and solid-state photoluminescence properties for these crystalline materials have been carried out.