Indiana University-Purdue University Indianapolis (IUPUI) / Metal-organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands in porous structure forms. MOFs have been proposed in use for gas adsorption, purification, and separation applications. This work combines MOFs with 3D printing technologies, in which 3D printed plastics serve as a mechanical structural support for MOFs powder, in order to realize a component design for gas adsorption. The objective of the thesis is to understand the gas adsorption behavior of MIL-101 (Cr) MOF coated on 3D printed PETG, a glycol modified version of polyethylene terephthalate, through a combined experimental and modeling study. The specific goals are: (1) synthesis of MIL-101 (Cr) MOFs; (2) nitrogen gas adsorption measurements and microstructure and phase characterization of the MOFs; (3) design and 3D printing of porous PETG substrate structures; (4) deposition of MOFs coating on the PETG substrates; and (5) Monte Carlo (MC) modeling of sorption isotherms of nitrogen and carbon dioxide in the MOFs. The results show that pure MIL-101 (Cr) MOFs were successfully synthesized, as confirmed by the scanning electron microscopy (SEM) images and X-ray diffraction (XRD), which are consistent with literature data. The Brunauer-Emmett-Teller (BET) surface area measurement shows that the MOFs samples have a high cover- age of nitrogen. The specific surface area of a typical MIL-101 (Cr) MOFs sample is 2716.83 m2/g. MIL-101 (Cr) also shows good uptake at low pressures in experimental tests for nitrogen adsorption. For the PETG substrate, disk-shape plastic samples with a controlled pore morphology were designed and fabricated using the fused deposition modeling (FDM) process. MOFs were coated on the PETG substrates using a layer-by-layer (LbL) assembly approach, up to 30 layers. The MOFs coating layer thicknesses increase with the number of deposition layers. The computational model illustrates that the MOFs show increased outputs in adsorption of nitrogen as pressure increases, similar to the trend observed in the adsorption experiment. The model also shows promising results for carbon dioxide uptake at low pressures, and hence the developed MOFs based components would serve as a viable candidate in gas adsorption applications.

Designing new materials for CO₂ capture and utilization is one of the most challenging research topics. Metal-organic frameworks (MOFs) are one of the most efficient CO₂ adsorbents, as well as an emerging class of heterogeneous catalysts for CO₂ chemical transformations. Highlighted by their high content of active centers, large internal surface areas, tunable pore size, and versatile chemical functionalities, MOFs can serve as highly stable and reusable heterogeneous catalysts and provide a great platform to explore the structure-function relationships for transforming CO₂ into useful chemicals. In this dissertation, we aim to develop a new class of metal-cyclam based robust MOFs as porous materials for CO₂ uptake as well as efficient catalysts for CO₂ chemical transformations, including CO₂ chemical fixation, CO₂ photo- and electroreduction. Chapter 1 introduces the concept and main challenges of CO₂ capture and conversion. The potential of metal-cyclam complexes as molecular catalysts for CO₂ conversion is also mentioned. The current state of the art in designing stable MOFs and azamacrocyclic-based MOFs is briefly discussed. Finally, the strategies, challenges and future outlook of using MOF as catalysts in CO₂ chemical transformation are summarized. Metal-organic frameworks (MOFs) as highly ordered, tunable hybrid materials have shown great promise in photon collection, energy transfer and photocatalytic reactions. In Chapter 2, the fundamental principles of energy transfer in the condensed phase are summarized, and a series of studies in light-harvesting, excited state quenching and photo-excited reactivity occurring within ruthenium-polypyridyl-doped zirconium MOFs are reviewed. The application of MOFs in energy conversion devices such as dye-sensitized solar cells (DSSC) is also discussed. Chapter 3 reports two new robust 3D porous metal-cyclam based Zr-MOFs, VPI-100 (Cu) and VPI-100 (Ni) with potential as heterogeneous catalysts for CO2 chemical fixation. The frameworks are prepared by a modulated synthetic strategy and the structure highlighted by eight-connected Zr₆ clusters and metallocyclams as organic linkers. The VPI-100 MOFs exhibit excellent chemical stability in various organic and aqueous solvents over a wide pH range and show high CO₂ uptake capacity (up to ∼9.83 wt% adsorption at 273 K under 1 atm). Moreover, VPI-100 MOFs demonstrate some of the highest reported catalytic activity values (turnover frequency and conversion efficiency) among Zr-based MOFs for the chemical fixation of CO₂ with epoxides. The MOFs, which bear dual catalytic sites (Zr and Cu/Ni), enable chemistry not possible with the cyclam ligand under the same conditions and can be used as recoverable stable heterogeneous catalysts without losing performance. A follow-up study of CO₂ chemical fixation using Hf analogs of VPI-100 is presented in Chapter 4. Structural characterization and catalytic performance of Hf-VPI-100 are summarized. Moreover, a detailed comparison of VPI-100 and Hf-VPI-100 is made. In situ powder X-ray diffraction (PXRD), quartz crystal microbalance (QCM) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) have been used to probe the interaction between the guest molecules (CO₂/epoxide) and Hf-VPI-100. For CO₂, no specific chemical binding sites in MOFs has been observed and the uptake of CO₂ does not change the crystal structure of Hf-VPI-100. Both QCM and DRIFTs revealed the irreversible binding between the framework and 1,2-epoxybutane. The epoxide uptake per unit cell of VPI-100 MOFs and diffusion coefficients have been calculated by QCM analysis. Transition metal complexes capable of visible light-triggered cytotoxicity are appealing potential candidates for photodynamic therapy (PDT) of cancer. In Chapter 5, two monometallic polyazine complexes, [(Ph₂phen)₂Ru(dpp)]²⁺ and [(Ph₂phen)₂Os(dpp)]⁺ (Ph₂phen = 4,7-diphenyl-1,10-phenanthroline; dpp =2,3-bis(2-pyridyl)pyrazine), were synthesized, characterized and studied as light activated drugs to kill rat malignant glioma F98 cells. Both compounds display strong absorption in visible spectrum, oxygen-mediated DNA and BSA photocleavage and significant photocytotoxicity under blue light irradiation along with negligible activity in the dark. The compounds show approximately five-fold higher cytotoxicity compared the traditional chemotherapeutic drug, cisplatin. Furthermore, [(Ph₂phen)₂Os(dpp)]⁺ shows promising photocytotoxicity in F98 rat malignant glioma cells within the phototherapeutic window with an IC50 value of (86.07±8.48) µM under red light (625 nm) irradiation. In Chapter 6, the mixed-metal supramolecular complex, [(Ph₂phen)₂Ru-(dpp)PtCl₂]²⁺, was found to display significant DNA modification, cell growth inhibition, and toxicity towards F98 malignant glioma cells following visible light irradiation. The design of this complex has a significantly higher potential for membrane permeability than three other FDA-approved anti-cancer agents, including cisplatin, and exhibited a dramatic ten-fold higher uptake by F98 cells than cisplatin in a two-hour window. Based on studies with a rat glioma cell line, the compound has very low cytotoxicity in the dark, but results in substantial cell death upon light treatment. The complex is thus among the first to exhibit all the hallmarks of a very promising new class of PDT agents. / Ph. D. / Increased carbon dioxide (CO₂) emissions have triggered a series of environmental effects, including global warming and ocean acidification. Scientists are trying to develop new materials to capture and convert CO₂ into useful chemical products. However, the main challenge is that CO₂, the gas generated upon burning fossil fuels, has strong C=O bonds that are hard to break. In other words, it is too stable to be easily changed into other compounds. A class of highly porous materials known as metal-organic frameworks (MOFs) possess significant potential for CO₂ adsorption uptake and chemical fixation. MOFs are metal ions or clusters held together by organic linkers to make highly ordered, crystalline 3D structures with tunable porosity and functionality. The design and synthesis of MOFs is similar to playing with Legos at the molecular level; you need to pick the right pieces (metal nodes and linkers) to get your desired structure. In this dissertation, we aim to develop a new class of macrocycle complexes based stable MOFs as porous materials for CO₂ uptake as well as efficient catalysts for CO₂ chemical transformations. We have developed two new stable three dimensional porous frameworks, VPI-100 (Cu) and VPI-100 (Ni) as catalysts for CO₂ chemical fixation. The new 3D robust MOFs named VPI-100 (VPI = Virginia Polytechnic Institute) are assembled by the reaction of zirconium oxo clusters and linkers bearing metal complexes. Using the metal complexes as the linker provides additional metal active sites in the framework that can act as accessible catalytic centers for CO₂ conversion. The VPI-100 MOFs are not only able to convert CO₂ to cyclic carbonates (important industrial chemicals) in high efficiency (~ 98%), but also can be reused for multiple cycles. The heterogeneous catalyst can be easily recovered from the reaction mixture by centrifugation and the active metal centers are earth-abundant transition metals (Cu and Ni), which are cost effective. Additionally, VPI-100 MOFs also show high CO₂ uptake capacity (up to ~10 wt%) at ambient pressure. Since the MOFs can enhance the local concentration of CO₂ around the active catalytic centers located inside the pores of the framework, these materials could be used as catalysts for flow chemistry, which is widely used in industry. We further investigated the CO₂ chemical fixation using Hf analogs of VPI-100. Structural characterization and catalytic performance of Hf-VPI-100 are summarized. Moreover, a detailed comparison of VPI-100 and Hf-VPI-100 is made. Different analytical techniques have been used to further understand the reaction mechanism as well as the interaction between the CO₂/epoxide and the frameworks. These insights would help us to design new MOFs as better catalysts for practical applications.

In dieser Arbeit werden das Potential der mechanochemischen Synthesemethode zur Herstellung von metallorganischen Gerüstverbindungen (MOFs) vorgestellt und mögliche Anwendungsgebiete aufgezeigt. Im Forschungsfokus bezüglich schnellerer und effizienterer Darstellungsmethoden ist die Mechanochemie eine aussichtsreiche Alternative. Die Feststoff-Reaktion ist ohne die Verwendung von Lösungsmitteln durchführbar, zeichnet sich durch verkürzte Reaktionszeiten und quantitativen Eduktumsatz aus und gilt somit als Green Chemistry-Methode, die stetig wachsende Bedeutung erlangt. Die Ergebnisse dieser Arbeit belegen, dass über die mechanochemische Synthese metallorganische Verbindungen in allen Dimensionalitäten herstellbar sind. Die Reaktionsparameter sind auf die Herstellung isostruktureller und strukturanaloger Verbindungen übertragbar. Es wurden Synthesebedingungen identifiziert, die die Produktbildung beeinflussen, so dass ihre Kontrolle zur gezielten Herstellung verschiedener Verbindungen diente. Des Weiteren wurden Reaktionsparameter ermittelt, die einen Einfluss auf die Eigenschaften des Produkts ausüben. Im Hinblick auf eine größtmögliche spezifische Oberfläche wurde die Synthese optimiert und eine postsynthetische Aktivierungsprozedur entwickelt, die gemeinsam in einer verbesserten Gasadsorptionskapazität resultieren und auf andere Verbindungen übertragbar sind. Die Ergebnisse zur Gasspeicherung zeigen ein erstes Anwendungspotential für mechanochemisch synthetisierte MOFs auf, die als feine Pulver mit vergrößerter Oberfläche erhalten werden. Weiterhin wurde die Einlagerung von Solvensmolekülen in die Poren eines MOFs untersucht. Dabei zeigte sich, dass das MOF seine Gitterparameter an die jeweiligen Gastmoleküle anpasst. Das Potential zur Interkalation von Feststoffen wird anhand der Einlagerung pharmazeutischer Wirkstoffmoleküle belegt. Katalytische Untersuchungen zeigen eine gute Aktivität des mechanochemisch synthetisierten Rohprodukts. / In this work the potential of mechanochemical synthesis to produce metal-organic frameworks (MOFs) is presented and possible applications for the materials are shown. In the focus of research regarding faster and more efficient methods of synthesis, mechanochemistry is an promising alternative. This solid-state reaction can be carried out without the use of solvent, exhibits shortened reaction times and a quantitative turnover of reactands. Therefore it is a method of green chemistry, and its importance is constantly increasing. The results show that mechanochemical synthesis is capable of producing metal-organic compounds in all dimensionalities. The reaction conditions can be transferred to synthesize isostructural and structural analogous compounds. Parameters influencing the formation of products were identified, and their control led to a well-aimed design of various compounds. In addition, conditions influencing the properties of the product were determined. In terms of a specific surface area as large as possible, the synthesis was optimized and a postsynthetic activation was developed, together resulting in an improved capacity for gas adsorption and transferrable to other compounds. The results concerning gas storage present one possible application of mechanochemically synthesized MOFs, that are produced as fine powders with enlarged surfaces. Furthermore, intercalation of solvent molecules in the pores of a MOF was investigated. It shows that the MOF adjustes its lattice paramters to the guest molecules. The potential to intercalate solid-state compounds is demonstrated using pharmaceutical drug molecules. Catalytic investigations show a good activity of the mechanochemically synthesized raw product.

Les Membranes à Matrices Mixtes (MMM’s) sont des matériaux prometteurs pour la capture de CO2 en comparaison aux technologies actuelles telles que l’absorption par solvants aminés (monoéthanolamine). Les ‘Metal-Organic Frameworks’ (MOFs) sont des matériaux poreux cristallins envisagés pour être intégrés sous forme de nanoparticules aux polymères des MMM’s. Ils résultent de la combinaison de nœuds métalliques et de ligands organiques pour former des structures tridimensionnelle (3D) organisées. Ils possèdent divers avantages : des aires spécifiques et des volumes poreux élevés, des tailles de pores contrôlables, et pour certains une stabilité à l’eau. Les MOFs ont une chimie adaptable aux applications souhaitées contrairement aux adsorbants classiques tels que les charbons actifs, les zéolithes.D’une part, ce travail a eu pour objectif l’évaluation des performances de séparation du CO2 par des MOFs microporeux en vue des séparations CO2/N2 et CO2/CH4. Les interactions ‘gaz-adsorbant’ sont favorisées au sein des MOFs par : (1) une réduction de la taille de pores et du volume poreux pouvant engendrer des effets de confinements, de tamis moléculaire ou (2) par la présence de groupements de surface. En conséquence, ces paramètres peuvent contribuer à l’amélioration de la sélectivité du CO2 et ont été étudiés pour divers systèmes de MOFs microporeux. D’autre part, les paramètres texturaux (aire spécifique, volume poreux) et thermodynamiques (enthalpies d’adsorption) ont été corrélés aux quantités maximales de CO2 adsorbées au travers d’une approche quantitative de relation de structure-propriété pour établir des tendances linéaires. / Mixte Matrix Membranes (MMM’s) are promising materials for CO2 capture compared to current technologies as absorption using amines solvents (monoéthanolamine). Metal-Organic Frameworks (MOFs) are crystalline porous materials which can be integrate under nanoparticles shape to polymer phase of MMM’s. They are built from metal nods and organic ligand to yield well-defined tridimensional structure (3D). They possess various advantages: high specific surface area and pore volume, tunable pore size and some of them are stable in presence of water. MOFs have a sustainable chemistry to targeted applications unlike traditional adsorbents as activated carbons, zeolites.On the one hand, this work aimed the assessment of CO2 separation performances of microporous MOFs for CO2/N2 and CO2/CH4 gas separations. The ‘gas-adsorbent’ interactions are favored in MOFs by: (1) a decrease of pore size, pore volume which can involve confinement effects, molecular sieve effects or (2) the presence of surface groups. Therefore, these factors can contribute to the CO2 selectivity improvement and have been studied for various microporous MOFs. On the other hand, textural (specific surface area, pore volume) and thermodynamic (adsorption enthalpy) parameters have been correlated to CO2 maximum excess uptakes through a quantitative structure-property approach to establish some linear trends.

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(Doctoral Thesis, 2016, Mgr. Tomáš Faukner, IONIC POLYACETYLENE TYPE POLYMERS AND POLYMER NETWORKS BY CATALYST FREE QUATERNIZATION POLYMERIZATION) The composition and structure of a series of ionic π-conjugated poly(monosubstituted acetylene)s prepared via catalyst-free quaternization polymerization (QP) of 2-ethynylpyridine (2EP) activated with equimolar amount of alkyl halide [RX = ethyl bromide, ethyl iodide, nonyl bromide and haxadecyl (cetyl) bromide] as a quaternizing agent (QA) have been studied in detail. The performed QPs gave ionic polymers well soluble in polar solvents, with approximately half of pyridine rings quaternized, which implies that also non-quaternized monomers were involved in the process of QP. The configurational structure of polyacetylene main chains was suggested based on 1 H NMR, IR as well as Raman (SERS) spectral methods. The QPs in bulk gave more expected irregular cis/trans polymers while the QPs in acetonitrile solution gave high-cis polymers. A series of prepared symmetrical bi-pyridylacetylene based monomers has been polymerized via QP approach resulting into a series of new ionic π-conjugated poly(disubstituted acetylene) type materials. It is therefore obvious that the mechanism of quaternization activation frequently applied on monosubstituted...

4 ABSTRACT The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated...