Crystal engineering of mixed-ligand metal-organic frameworks

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dc.contributor.advisorOliver, Clive Len_ZA
dc.contributor.authorTahier, Tayyibahen_ZA
dc.date.accessioned2017-01-23T07:54:39Z
dc.date.available2017-01-23T07:54:39Z
dc.date.issued2016en_ZA
dc.description.abstractResearch of solid state complexes has grown and developed exponentially over the past few years in terms of supramolecular chemistry and crystal engineering. The synthesis and characterisation of metal organic frameworks (MOFs) have attracted widespread attention owing to their potential in various applications. This includes gas sorption, which could aid in alleviating serious environmental issues such as global warming by sequestrating greenhouse gases. Advances in the design of these materials using the mixed ligand approach add to variation in structures and thus provide a further means of tailoring of properties. A novel two dimensional, mixed ligand MOF has been synthesised based on 1,3,5 benzenetricarboxylic acid, 4,4' bipyridine N,N' dioxide and zinc sulfate with the formula [Zn3(BTC)(4,4' bpdo)(OH)(SO4)(H2O)3]n·n(H2O)2.33 (1). The 2D layers of 1 arrange in a polar fashion with adjacent layers forming isolated cavities. Variable temperature powder X ray diffraction (VT PXRD) analysis showed that the crystallinity of the compound was retained and the crystalline phase remained unchanged as the temperature was increased. Variable temperature single crystal X ray diffraction (VT SCXRD) analysis of 1 revealed that the dehydration and rehydration processes occur via single crystal to single crystal transformations. Water vapour sorption experiments showed a type I isotherm, typical of microporous materials. A two dimensional, interpenetrated, mixed ligand MOF has been synthesised based on 5 nitro 1,3 benzenedicarboxylic acid, 1,2 bis(4 pyridyl)ethane and cadmium nitrate with the formula [Cd(bpe)1.5nbdc]·DMF (2). VT PXRD analysis shows subtle differences in the compound as the temperature is increased. VT SCXRD experiments show that the most notable change in the structure occurs at 373 K. These changes include the removal of the guest molecule and a change in the crystal system, along with changes in the orientation of the pyridyl ring of the organic ligand. Carbon dioxide sorption experiments at 195 K showed a type IV isotherm, which is usually associated with mesoporous materials. Both 1 and 2 were synthesised using the solvothermal method and fully characterised using X ray diffraction studies (SCXRD, PXRD, VT SCXRD and VT PXRD), thermal analysis (thermogravimetric, differential scanning calorimetry, hot stage microscopy), elemental analysis and FT IR spectroscopy. The porosity of the compounds was tested using carbon dioxide (273 K and 193 K), nitrogen, water vapour and liquid sorption experiments.en_ZA
dc.identifier.apacitationTahier, T. (2016). <i>Crystal engineering of mixed-ligand metal-organic frameworks</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/22913en_ZA
dc.identifier.chicagocitationTahier, Tayyibah. <i>"Crystal engineering of mixed-ligand metal-organic frameworks."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Chemistry, 2016. http://hdl.handle.net/11427/22913en_ZA
dc.identifier.citationTahier, T. 2016. Crystal engineering of mixed-ligand metal-organic frameworks. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Tahier, Tayyibah AB - Research of solid state complexes has grown and developed exponentially over the past few years in terms of supramolecular chemistry and crystal engineering. The synthesis and characterisation of metal organic frameworks (MOFs) have attracted widespread attention owing to their potential in various applications. This includes gas sorption, which could aid in alleviating serious environmental issues such as global warming by sequestrating greenhouse gases. Advances in the design of these materials using the mixed ligand approach add to variation in structures and thus provide a further means of tailoring of properties. A novel two dimensional, mixed ligand MOF has been synthesised based on 1,3,5 benzenetricarboxylic acid, 4,4' bipyridine N,N' dioxide and zinc sulfate with the formula [Zn3(BTC)(4,4' bpdo)(OH)(SO4)(H2O)3]n·n(H2O)2.33 (1). The 2D layers of 1 arrange in a polar fashion with adjacent layers forming isolated cavities. Variable temperature powder X ray diffraction (VT PXRD) analysis showed that the crystallinity of the compound was retained and the crystalline phase remained unchanged as the temperature was increased. Variable temperature single crystal X ray diffraction (VT SCXRD) analysis of 1 revealed that the dehydration and rehydration processes occur via single crystal to single crystal transformations. Water vapour sorption experiments showed a type I isotherm, typical of microporous materials. A two dimensional, interpenetrated, mixed ligand MOF has been synthesised based on 5 nitro 1,3 benzenedicarboxylic acid, 1,2 bis(4 pyridyl)ethane and cadmium nitrate with the formula [Cd(bpe)1.5nbdc]·DMF (2). VT PXRD analysis shows subtle differences in the compound as the temperature is increased. VT SCXRD experiments show that the most notable change in the structure occurs at 373 K. These changes include the removal of the guest molecule and a change in the crystal system, along with changes in the orientation of the pyridyl ring of the organic ligand. Carbon dioxide sorption experiments at 195 K showed a type IV isotherm, which is usually associated with mesoporous materials. Both 1 and 2 were synthesised using the solvothermal method and fully characterised using X ray diffraction studies (SCXRD, PXRD, VT SCXRD and VT PXRD), thermal analysis (thermogravimetric, differential scanning calorimetry, hot stage microscopy), elemental analysis and FT IR spectroscopy. The porosity of the compounds was tested using carbon dioxide (273 K and 193 K), nitrogen, water vapour and liquid sorption experiments. DA - 2016 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2016 T1 - Crystal engineering of mixed-ligand metal-organic frameworks TI - Crystal engineering of mixed-ligand metal-organic frameworks UR - http://hdl.handle.net/11427/22913 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/22913
dc.identifier.vancouvercitationTahier T. Crystal engineering of mixed-ligand metal-organic frameworks. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Chemistry, 2016 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/22913en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemistryen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherChemistryen_ZA
dc.titleCrystal engineering of mixed-ligand metal-organic frameworksen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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