Shimizu, George Kisa HayashiGabert, Evan Darryl2024-09-242024-09-242024-09-20Gabert, E. D. (2024). Template-directed design of robust phosphonate metal-organic frameworks for carbon capture (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.https://hdl.handle.net/1880/119873Metal-organic frameworks are versatile and tunable materials. Phosphonate MOFs offer greater stability, but structural control is challenging. This thesis utilizes hydrogen-bonded metal-organic framework (HMOF) intermediates to control phosphonate MOF properties. HMOFs are porous hydrogen-bonded solids composed of secondary sphere interactions between phosphonate linkers and hexaaquachromium(III) ions. HMOFs are metastable and well ordered. Thus, they serve as an isolatable intermediate that is easily characterized. Upon heating, aqua ligands are irreversibly replaced by phosphonates. While the resulting MOFs are often poorly ordered, they retain properties of their prior HMOF structure. This work shows the flexibility of HMOF hydrogen bonds allow guest molecules to substantially change framework structure. If the guest is retained during dehydration, it will continue to shape pore structure and result in a unique MOF. The resulting MOFs are rigid and retain the guest-imprinted pore structure after guest removal. This “HMOF to MOF” method allows for the controlled synthesis of robust phosphonate MOFs. This proof-of-concept study develops the HMOF to MOF method towards the creation of solid sorbents for carbon capture. A novel highly flexible HMOF, H-CALF-55, was dehydrated in the presence of numerous guests. This resulted in formation of unique MOF structures with tunable isotherm shape and gas capacity (0.5 to 1.2 mmol/g). The MOFs retained their gas capacity after one week of exposure to boiling water or 6 M HCl. The unconventional use of CO2 guests resulted in 1.5 times higher CO2 capacity than guest-free synthesis. Lastly, the use of template mixtures to form MOFs imprinted by guest-guest interaction was explored. H-CALF-55 dehydrated around a combination of CO2 and water had increased CO2 capacity relative to the single-guest MOFs. Amine modified HMOFs were dehydrated around trace water. The resulting MOFs exhibited 3-fold higher CO2 capacities at 40 mbar when wetted prior to analysis with 5.2 mass percent water. No such effect was observed in MOFs prepared from bulk water. This suggests that the template used can have great impact on MOF properties, including tuning material performance in the presence of water. A critical metric for carbon capture materials.enUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Metal-Organic FrameworkTemplateCarbon CaptureHydrogen BondedChemistry--InorganicMaterials Sciencedoctoral thesis