Constructions And Properties Of Zeolite-like Supramolecular Assemblies Based On The Derivatives Of Imidazoledicarboxylate

As new functional materials, coordination polymers have potential applications ingas adsorption and separation, catalysis, optical, sensing and magnetism, owning totheir tunable structure and function. In the synthesis of MOFs, selection of organicligand plays an important role on their structure and function. In recent years,introducing different functional groups onto organic ligands to obtain functional MOFsmaterials is one of the major progresses.In this thesis, we synthesized six different ligands by modifying the4,5-imidazoledicarboxylic acid ligand (ImDC). They are2-Amino-ImDC,2-Hydroxymethyl-ImDC,2-propyl-ImDC,2-phenyl-ImDC, D-2-Hydroxyethyl-ImDCand L-2-Hydroxyethyl-ImDC (L1-L6). Among them, we use ligands L1-L4to synthesizea series of porous zeolite-like supramolecular assemblies (ZSAs) with gis topology andexplore their gas adsorption properties; Two chiral ZSAs were synthesized by usingligands L5-L6and their chiral properties were studied.Under hydrothermal conditions, a series of ZSAs were synthesized by using ImDCderivatives as ligands, cobalt acetate as a metal source, and1,2-propane diamine(1,2-PDA) as a second ligand. The four obtained ZSAs compounds with gis topology,were constructed from functional metal-organic squares (MOSs) via intermolecularhydrogen-bonding interactions. All the compounds exhibit good thermal stability andtheir frameworks can be stable up to300oC after removed the guest water molecules.N2and Ar gas sorption studies indicate that they have similar pore volume and largesurface area, but exhibit different CO2adsorption properties. At room temperature, themaximum CO2uptake and the highest adsorption enthalpy (Qst) for compounds1and2are higher than compounds3and4. It shows that the introducing of different functionalgroups has effect on CO2sorption, amino and hydroxyl groups show stronger interaction with CO2than phenyl and propyl groups.Two chiral supramolecular compounds5a and5b were assembled from D-,L-2-Hydroxyethyl-ImDC, cobalt acetate and1,2-PDA under hydrothermal conditions.Compounds5a and5b are isostructural to compound1. These two compounds showgood thermal stability, and the BET surface area of compound5a and5b is724,797m2/g, respectively. CD spectroscopy shows that the two compounds are a pair ofenantiomers. Therefore, compounds5a and5b with chiral channels may be having thepotential application in the separation of small chiral molecules.