In this thesis I researched an efficient method of functionalisation of metal-organic frameworks (shortened MOFs) – post-synthetic modification of zeolitic imidazolate frameworks (shortened ZIFs) based on solvent-assisted ligand exchange (shortened SALE).
Research was made on a well known ZIF named ZIF-8. The work included adaptation of literature ZIF-8 monocrystal synthesis procedures and further SALE on prepared monocrystals. Two solvothermal methods were found as efficient preparations of ZIF-8 monocrystals, first one using methanol (shorter MeOH) and the second one using N,N-dimethylformamide (shorter DMF). SALE was then also performed using MeOH and DMF as solvents to test solvent impact on framework stability during the procedure. The 15 linkers used for SALE were the following: 5-iodo-2-methyl-1H-imidazole, 4-bromo-1H-imidazole, 2-acetylthiazole, 2,4-dimethylthiazole, 2-methyl-5-nitroimidazole, 2-nitroimidazole, 4-nitroimidazole, 4-bromo-2-methyl-1H-imidazole, 1-vinyl-1H-imidazole, 2-isopropyl-1H-imidazole, 1H-imidazole-4-carbaldehyde, methyl 1H-imidazole-2-carboxylate, 4-iodo-1H-imidazole, 4-methyl-1H-imidazole-5-carbaldehyde and 5-methyl-1H-imidazole-4-methanol.
For sample characterisation multiple techniques and methods were used, those being single-crystal X-ray diffraction (shortened SXRD) and X-ray powder diffraction (shortened XRPD), thermogravimetric analysis (shortened TGA), scanning electron microscopy (shortened SEM), energy dispersive spectroscopy (shortened EDS), infrared spectroscopy (shortened IR) and nitrogen physisorption. Lastly carbon dioxide isotherms were collected for select samples to study their efficiency in adsorption of carbon dioxide.
Samples ZIF8-DMF and DMF-IZOP-M+D proved to be the two materials best suited for CO2 capture. The first is ZIF-8, which was prepared in the solvent DMF and on which SALE was not performed. The second is ZIF-8, which was also prepared in the solvent DMF, but on which SALE was performed with the exchange linker 2-isopropyl-1H-imidazole in a mixed solvent of MeOH and DMF in a ratio of 1 / 1.
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