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Die Forschung an porösen Hybridmaterialien hat sich rasch entwickelt, und in letzter Zeit ist die Anzahl neuer Strukturen und Zusammensetzungen aufgrund ihrer vielfältigen Anwendungsmöglichkeiten im Bereich des Kristall-Engineering von großem Interesse. Metall-organische Gerüste (metal-organic frameworks, MOFs) sind eine aufstrebende Klasse von Nanomaterialien, deren Eigenschaften durch Variation der Bausteine, die aus Metallionen und organischen Liganden bestehen und sich koordinativ zu einer dreidimensionale Struktur verbinden lassen, leicht angepasst werden können. Eigenschaften wie eine große Oberfläche und eine hohe Porosität verleihen diesen Materialien vielversprechende Eigenschaften, um als Wirtsmaterial verwendet zu werden. Die vorliegende Arbeit konzentriert sich auf die Synthese der Verbindung [Fe3O(H2O)2(OH)(bdc)3]n (bcd = 1,4-Benzoldicarboxylat; MIL-101(Fe), MIL = Materials of Institut Lavoisier), die aus einem carboxylato-verbrückten, oxido-zentriertem, dreikernigen Fe3+-Komplex besteht. Die Struktur besitzt große Poren (Ø: 29 und 34 Å) und eine große Oberfläche mit der Fähigkeit, zahlreiche Moleküle einzuschließen. In der vorliegenden Arbeit wird MIL-101(Fe) als Arzneimittelabgabesystem verwendet. Curcumin, Capecitabin und 5-Fluorouracil (5-FU) wurden als Modellarzneimittel für die Verkapselung in der MIL-101(Fe)-Struktur ausgewählt. Es wurden verschiedene Freisetzungsregime in unterschiedlichen biologischen Medien untersucht. Nach vielversprechenden ersten Ergebnissen bei der Freisetzung dieser Medikamente aus der MIL-101(Fe)-Struktur wurde anschließend die selektive Lasersintertechnik (SLS) verwendet. Die SLS ist ein additives Schichtbauverfahren, das sich in dieser Arbeit als ressourcenschonende Technologie für die schnelle Herstellung erwiesen hat. Die Möglichkeit, die Größe, Form und Geometrie der hergestellten Proben individuell anzupassen, bot die Gelegenheit, die Wirkstofffreisetzung zu modulieren und den Freisetzungszeitraum zu verlängern. / The field of porous hybrid materials has grown rapidly; recently the number of new structures and compositions are of great interest in the crystal-engineering field, due to their various possible applications. Metal-organic frameworks (MOFs) are an emerging class of nanomaterials, whose properties can be easily adjusted by varying the molecular building blocks, obtained from metal ions and organic ligands that can be combined to three-dimensional structures. Properties such as high surface area and high porosity give these materials promising characteristics to be used as host materials. The present work focuses on the synthesis of [Fe3O(H2O)2(OH)(bdc)3]n (bcd = 1,4-benzenedicarboxylate; MIL-101(Fe), MIL = Materials of Institut Lavoisier), composed of carboxylate-bridged, oxido-centered, trinuclear Fe3+ complexes. The iron-based structure features large pore sizes (Ø: 29 and 34 Å) and high surface area with the ability to encapsulate numerous molecules, for use as a drug delivery system in the present work. The curcumin, capecitabine, and 5-fluorouracil (5-FU) were chosen as model drugs for the encapsulation into the MIL-101(Fe) structure. Different delivery regimes were studied in different biological media. After promising initial results with the release of these drugs from the MIL-101(Fe) structure, the selective laser sintering technique (SLS) was introduced subsequently. The SLS is an additive layer manufacturing technique that has emerged in this work as a resourceful technology for rapid manufacturing, the possibility to customize the size, shape, and geometry of the manufactured samples, thus providing the opportunity to modulate the drug release extending it for even longer periods of time.

Metal-organic frameworks (MOFs) are a class of highly crystalline nanoporous materials that self-assemble from inorganic metal oxide clusters and multitopic organic linkers. MOFs can be altered in terms of the types of metals and structures of organic linkers used, allowing for a high degree of customization and manipulation of the synergistic chemical or physical properties that arise from the precise coordination of their molecular components, including exceptionally large surface area and pore size. Zirconium-based MOFs, called UiOs in honor of their conception at the University of Oslo, also show remarkable chemical stability in both acidic and basic environments, making them excellent candidates for biomedical applications as drug delivery systems, where they can either function as molecular cargo ships, with drugs packed into their pores, or as controlled release systems, in which drug molecules are directly attached to their ligands for precise delivery. The objective of this work is to prepare water-stable MOFs whose linkers are decorated with functional groups that have potential compatibility in drug delivery systems and to explore the efficacy of certain synthesis conditions in terms of the crystallinity of the MOF product. Thus, we hope to establish a basis for the ligation of anticancer drugs and fluorescent tags to MOFs for their controlled release at a specified location within the body. These targeted release mechanisms represent new therapeutic possibilities in terms of cancer treatment as their specificity would mitigate damage to healthy tissues, thereby addressing one of the greatest weakness of present treatment options.

No description available.

Metal-organic frameworks (MOFs) are a class of hybrid materials that offer a promising platform for a range of catalytic reactions. Due to their complex structure, MOFs offer unique opportunities to serve as novel catalysts, or as host to improve the properties of previously studied species. However, while other catalytic approaches have been studied for many decades, the recency of their discovery means that significant work is still needed to develop MOFs as a viable option for large scale application. Herein, we aimed to advance the field of MOFs as both novel catalysts, and as host platforms for other catalytic species. To this end, we studied synthetic pathways to produce favorable MOF properties such as higher porosity and active site concentration through introduction of defects and macromorphological control, as well as utilization of molecular catalysts imbedded in the MOF structure for multicomponent, light driven reactivity. Chapter 1 introduces the history MOFs and the pursuit of the stable structures commonly associated with MOF chemistry. The synthesis process for zirconium-based MOFs will be discussed, with specific attention given to the modulated synthesis process which can harnessed to change MOF properties and improve catalysis. Two specific reactions will be introduced which serve as a basis for study in this work. First, the hydrolysis of organophosphate nerve agents by MOFs acting as novel catalysts will be introduced. The mechanism of reaction, as well as previous work in this field will be discussed. Finally, water oxidation as part of artificial photosynthesis through incorporated molecular catalysts will be introduced. Chapter 2 presents a modulator screening study on a zirconium-based MOF, UiO-66. One of the most commonly studied MOFs, UiO-66 provides an excellent platform for synthetic modulation. Particle size and defect level were measured of 26 synthetic variations and synthetic conditions were found to isolate changes in defect level and particle size, which typically change coincident with each other. Hydrolysis of the organophosphate compound dimethyl 4-nitrophenylphosphate (DMNP) was used to study the impact of particle size and defect level on reactivity. The reaction was found to be surface limited, even at high levels of missing linker defects. In Chapter 3, the macromorphology of three zirconium-based MOFs were tuned through synthesis modification. MOF powders and xerogels were prepared and characterized to highlight the desirable properties obtained through the gelation process. The materials were compared in the hydrolysis of DMNP and significant enhancement was observed for UiO-66 and NU-1000 xerogels. This was largely attributed to the introduction of mesoporosity and nanocrystalline particle sizes, which significantly increase the number of reactive sites easily accessible for catalysis. In Chapter 4 the authors examine MOFs as a host for molecular catalysts for use in photoelectrochemical water oxidation. A ruthenium-based catalyst [Ru(tpy)(dcbpy)]2+ was incorporated into UiO-67 through a mixed linker synthesis and grown on a WO3 substrate (Ru-UiO-67/WO3). Previous work from our group demonstrated Ru-UiO-67 retained the catalytic activity as the molecular species, while improving the recyclability of the material. In this work, addition of WO3 as a light harvester allowed for the reaction to be driven at a photoelectrochemical underpotential, a first for MOF-based water oxidation. Finally, Chapter 5 offers a perspective of the field of MOF-based artificial photosynthesis. Particular attention is given to issues of diffusion, selectivity, stability, and moving towards integration of multiple components rather than the study of half-reactions. / Doctor of Philosophy / Catalysts are a key component of chemistry that has a major impact on everyday life. From biological examples to industrial settings, catalysts are used to facilitate chemical conversions to new products and compounds. Because of the high demand, development of new catalysts with improved reactivity is a significant scientific challenge. A new class of materials known as metal-organic frameworks (MOFs) have been recently shown to acts as new catalysts or improve the properties of existing catalysts. Herein, we discuss the use of MOFs as catalysts for both development of new catalysts and improving known species. MOF-based catalysts have been used in a range of reactions from destruction of toxic chemical weapons to the production of renewable energy through artificial photosynthesis. This work is intended to highlight the potential for MOF-based catalysts and the next steps to further realize their potential.

Adsorption, separation and conversion of CO₂ from industrial processes are among the priorities of the scientific community aimed at mitigating the effects of greenhouse gases on the environment. One of the main focuses is the capture of CO₂ at stationary point sources from fossil fuel emissions using porous crystalline materials. Porous crystalline materials can reduce the energy costs associated with CO₂ capture by offering high adsorption rates, low material regeneration energy penalties and favorable kinetic pathways for CO₂ separation. MOFs consist of polymeric inorganic networks with adjustable chemical functionality and well-defined pores that make them ideal for these applications. The objective of this research was to test the potential for CO₂ capture on Zn-based MOFs by studying their sorption, transport and gas separation properties as adsorbents and continuous membranes. Three Zn-based MOFs with open Zn-metal sites were initially studied. Zn4(pdc)4(DMF)2•3DMF (1) exhibited the best properties for CO₂ capture and was investigated further under realistic CO₂ capture conditions. The MOF exhibited preferential CO₂ adsorption based on a high enthalpy of adsorption and selectivity of CO₂ over N₂ and CH₄. Sorption dynamics of CO₂ indicated fast adsorption and a low activation energy for sorption. Diffusion inside the pores is the rate-limiting step for diffusion, and changes in the process temperature can enhance CO₂ separation. Desorption kinetics indicated that CO₂ has longer residence times and lower activation energies for desorption than N₂ and CH₄. This suggests that the selective adsorption of CO₂ is favored. MOF/Polymer membranes were synthesized via a solvothermal method with structural defects sealed by a polymer coating. This method facilitates the permeation measurements of materials that cannot form uniform-defect-free layers. The membrane permeation of CO₂, CH₄, N₂ and H₂ exhibited a linear relation to the inverse square root of the molecular weight of the permanent gases, indicating that diffusion occurs in the Knudsen regime. Permselectivity was well-predicted by the Knudsen model with no temperature dependence, and transport occurs inside the pores of the membrane. MOF (1) exhibits ideal properties for future applications in CO₂ capture as an adsorbent. / Ph. D.

Many applications of metal-organic frameworks (MOFs) are highly dependent on their structures. The type and consistency of structure inform their properties. Zinc-based MOFs are applicable in different fields because of the low toxicity of zinc materials and are therefore also useful for catalysis. While MOF-5, a zinc-based MOF with carboxylate linkers is moisture intolerant, a variant of this is moisture tolerant. The introduction of a nitrogen-based linker in the zinc MOF which renders the structure moisture-tolerant. This material has not been explored as much, despite its multifunctional properties. Furthermore, the growth of Zn-based bimetallics of this MOF has not yet been explored. In this work, I studied the synthesis of this zinc-based moisture-tolerant MOF-5 as a thin film using a simple, fast, and cost-effective layer-by-layer wet synthesis method on different substrate surfaces. I successfully synthesized a series of bimetallics of this MOF as thin films on an untreated silicon wafer substrate. The successful synthesis of these materials was confirmed using X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy techniques. Additionally, some software data analysis tools were used for the characterization of the surface of the thin films to quantify the chemical composition. Future applications of these materials will be as sorbent materials for the capture of CO2 and its subsequent conversion to CO which is a synthesis gas for different useful materials like fuel and other chemical materials.

Nerve agents are acetylcholinesterase inhibitors and among the most toxic chemical warfare agents ever synthesized. Detection of these chemicals is critical for the protection of populations and strategic resources. G-series nerve agents are volatile compounds. V-series nerve agents are persistent phosphonothioate compounds. Persistent nerve agents do not readily volatilize and can contaminate environmental resources for extended periods. While nerve agents are inherently non-electroactive, they can be hydrolyzed to electroactive products compatible with electrochemical sensing. Zr(IV) MOFs are next-generation nanoporous materials, which have been shown to rapidly catalyze nerve agent hydrolysis. In this work, the catalytic processes of MOF-808, a specific Zr(IV) MOF, towards nerve agents are leveraged to develop novel Zr(IV) MOF-enabled electrochemical sensors capable of sensitively detecting both G-series and V-series nerve agents. Initially, a Zr(IV) MOF-enabled potentiometric sensor was developed for G-series nerve agent detection. The potentiometric sensor was tested using G-series nerve agent simulants, dimethyl methylphosphonate (DMMP) and diisopropyl fluorophosphate (DIFP). The potentiometric sensor had a limit-of-detection (LOD) of 185 and 20 µM for DMMP and DIFP, respectively. Following the potentiometric sensor, a Zr(IV) MOF-enabled voltammetric sensing strategy using sequential hydrolysis and detection for low-concentration detection of V-series nerve agents was developed. The full range of operation for the V-series nerve agent sensor was demonstrated using MOF-808 and a V-series nerve agent simulant, demeton-S methylsulphon (DMTS). MOF-808 was shown to rapidly, selectively, and completely hydrolyze DMTS into electroactive products. A LOD of 30 nM for DMTS was measured for this preliminary sensor. A sensor platform was developed to improve sensor applicability with smaller sample sizes and concurrent hydrolysis and detection. Furthermore, various alkaline buffers were studied to minimize background currents. The response of the developed sensor was evaluated for both DMTS and VX and demonstrated an LOD of 4 µM and 10 µM, respectively. The sensor also detected the presence of DMTS and VX from environmental samples in a simulated warfare scenario. This work demonstrates the feasibility of sensitive, rapid, and robust electrochemical sensing of both G-series and V-series nerve agents for in-field applications.

Yes / Grinding solid reagents under solvent-free or low-solvent conditions (mechanochemistry) is emerging as a general synthetic technique which is an alternative to conventional solvent-intensive methods. However, it is essential to find ways to scale-up this type of synthesis if its promise of cleaner manufacturing is to be realised. Here, we demonstrate the use of twin screw and single screw extruders for the continuous synthesis of various metal complexes, including Ni(salen), Ni(NCS)2(PPh3)2 as well as the commercially important metal organic frameworks (MOFs) Cu3(BTC)2 (HKUST-1), Zn(2-methylimidazolate)2 (ZIF-8, MAF-4) and Al(fumarate)(OH). Notably, Al(fumarate)(OH) has not previously been synthesised mechanochemically. Quantitative conversions occur to give products at kg h−1 rates which, after activation, exhibit surface areas and pore volumes equivalent to those of materials produced by conventional solvent-based methods. Some reactions can be performed either under completely solvent-free conditions whereas others require the addition of small amounts of solvent (typically 3–4 mol equivalents). Continuous neat melt phase synthesis is also successfully demonstrated by both twin screw and single screw extrusion for ZIF-8. The latter technique provided ZIF-8 at 4 kg h−1. The space time yields (STYs) for these methods of up to 144 × 103 kg per m3 per day are orders of magnitude greater than STYs for other methods of making MOFs. Extrusion methods clearly enable scaling of mechanochemical and melt phase synthesis under solvent-free or low-solvent conditions, and may also be applied in synthesis more generally. / EPSRC (EP/L019655/1)

Ce travail porte sur la cristallochimie de polymères de coordination poreux, ou Metal-Organic Frameworks (MOFs), pour la séparation et la catalyse énantiosélective. Les molécules chirales sont d'une importance capitale et jouent un rôle important dans la reconnaissance moléculaire. Il est donc nécessaire de pouvoir synthétiser un seul énantiomère ou de pouvoir séparer un mélange. La particularité des polymères de coordination à bénéficier d'une partie organique est la possibilité d'introduire des fragments chiraux dans la structure-même des matériaux. Nous avons décidé d'introduire la chiralité dans les MOFs par utilisation de ligands carboxylates originaux chiraux à cœur fluorène. Le premier chapitre de ce mémoire est consacré à l'étude bibliographique des MOFs avec une description des concepts de cette chimie qui permet de comprendre la stratégie mise en place dans cette étude. Le deuxième chapitre décrit la stratégie de synthèse des ligands ainsi que leurs caractérisations. Les trois chapitres suivants décrivent la synthèse, les structures cristallines et les caractérisations physico-chimiques de séries de MOFs regroupés par métal utilisé pour leur élaboration (Zn, Cd et Cu). Ces trois chapitres exposent les problématiques généralement rencontrées avec les MOFs, comme la perte de porosité par interpénétration des réseaux, et les stratégies mises en place pour les contourner, comme l'augmentation de la taille et de la fonctionnalité des ligands utilisés. Enfin la réactivité thermique et chimique des MOFs a été investiguée par diffraction des rayons X par la poudre afin de comprendre les mécanismes réactionnels et la création éventuelle de sites acides en vue d'applications en catalyse. Les techniques expérimentales sont détaillées dans le dernier chapitre de ce mémoire. Enfin un récapitulatif de cette étude est présenté afin de conclure sur la stratégie exposée dans ce mémoire et les perspectives offertes par cette étude. / This work deals with crystallochemistry of new porous coordination polymers or Metal-Organic Frameworks (MOFs) for enantioselective separation and catalysis. Chiral molecules are of a key role in molecular recognition as a consequence the ability to synthesize only one enantiomer or to separate a mixture is priority for chemistry. The particularity of coordination polymers to possess an organic part gives the possibility to introduce chiral fragments in the material structure. We decided to introduce chirality on MOFs by using originals chiral carboxylates ligands with fluorene core. The first chapter is devoted to the bibliographic study of porous coordination polymers. The second chapter describes the ligands synthesis strategy and characterizations. The next three chapters group the crystal structures and physicochemical characterizations of coordination polymers according to the metal used for their preparation (Zn, Cd et Cu). These three chapters explore also the general issues related to MOFs as the loss of porosity consequent to frameworks interpenetration, and strategies implemented to circumvent, such as increasing the size and functionality of the ligands used. Finally the thermal and chemical reactivity of MOFS has been investigated by powder X rays diffraction in order to understand reactions mechanisms and eventually the creation of acid sites for catalytic applications. The experimental technics are detailed in the last chapter. Finally a summary of this work closes this thesis showing the future perspectives of this work.