The metal-organic framework (MOF) research activities can be classified into MOF preparation, MOF processing, and MOF application. Processing MOFs into specially ordered shapes and morphologies is of great importance, since it bridges MOFs to real-life applications. Additionally, creating higher-order mesoscopic architectures with MOF particles as building blocks can introduce novel properties besides the inherent features of MOFs, thus opening a door to enhancing their performance in various applications. This thesis focused on the fabrication of MOFs into zero-dimensional and three-dimensional MOF architectures via various concepts inspired by polymerization and interfacial techniques. • A raspberry-like MOF-polymer microsphere was prepared via dispersion polymerization. MOFs were found to be a good stabilizer and could be bound to polymer core with the help of polyvinylpyrrolidone. The prepared microsphere could be further developed into a polymer@MOF core-shell structure. • A multilayered MOF colloidosome (MOFsome) was prepared through transient Pickering emulsion. The obtained MOFsome could be used as a stimulus-responsive carrier and as a general platform for construction of multicomponent colloidosomes. • A porous MOF monolith was obtained using high internal phase emulsion template (HIPE). MOF particles were able to stabilize HIPE with internal phase up to 90 % of the volume. The obtained monoliths were ultralight with density as low as 12 mg/cm3. • A flexible and porous nanocellulose aerogel with high MOF loadings was prepared through a straightforward sol-gel process, followed by freeze-drying. The hierarchical porous hybrid aerogel remained intact under compression and was demonstrated to be an ideal absorbents for water purification. • A shapeable and versatile platform was demonstrated for in situ growth of MOF particles. The metal ion cross-linked alginate hydrogels were converted into MOF-alginate composites through a post-treatment of the hydrogels with MOF ligand solution. The macroscopic shape of the composite could be controlled and it was demonstrated to be an effective absorbent for water purification. / Dissertation / Doctor of Philosophy (PhD)

No description available.

With the emission of carbon dioxide (CO2) becoming an international worry due its role in climate change, solutions such as CO2 capture and storage technologies are needed to decrease the emissions. The main proportion of CO2 gas emissions is from fossil fuel combustion in a range of industries, including power generation. To develop the CO2 capture system for these operations, new materials are needed for CO2 capture. Metal-organic framework (MOF) materials have porous crystal structures containing organic molecules (organic ligands) linked to each other by metalcontaining nodes. The large internal surface area can be exploited for the adsorption of small gas molecules, and for this reason MOFs may be ideal candidate materials for CO2 capture and gas separations. Thousands of MOF materials have been reported, with different combinations of the ligands and metals and with the capability of forming many different network topologies. Experimentally it is very difficult to study the gas absorption dynamics, interaction and gas adsorption capacity for the large number of materials. This problem can be solved by simulations. The aim of the thesis is to develop a systematic simulation method to screen the MOF properties and CO2 adsorption capacity and interaction dynamics at different environment. The molecular dynamics (MD) method with parameterised force fields was used to study the interactions between CO2 molecules and one class of the MOFs, zeolitic imidizolate frameworks (ZIFs) with zinc as the metal cation. To develop the model, the atom charges have been developed by using the distributed multipole analysis (DMA) method based on ab initio DFT calculations for molecules and clusters. The intermolecular forces were developed by fitting against the MP2 calculations of small clusters of the metal cations and molecular ligands. In order to evaluate the models I simulated the gas-liquid coexistence curve of CO2 and showed that it is consistent with experiments. I also simulated the pure ZIF structures on changing both temperature and pressure, demonstrating the stabilities of the structures but also showing the existence of displacive phase transitions. I have used this approach to successfully study CO2 absorption in a number of ZIFs (from ZIF-zni, ZIF-2, ZIF-4, ZIF-8 and ZIF-10) using MD. The gas absorption capacity and dynamics have been investigated under 25 bar and 30 bar, 200 , showing a promising uptake of CO2. The results have shown that CO2 capacity is mainly determined by the pore sizes and pore surfaces, in which a higher capacity is associated with a higher pore surface. The intermolecular distance of CO2 inside the pores and channels have been investigated in the saturation state. It has been shown that the distance is approximately 4 Å. The attraction force is from the interaction between CO2 and the imidazolate ligands. In addition, the systematic studies of the saturated ZIF system gave the minimum diameters for CO2 adsorption which is approximately 4.4 Å. This interaction has caused the gate opening effects, with the imidazolate ligands being pushed to be parallel to the CO2 molecules and opening up to allow more gas molecules go through the channels that connect the pore structures. This gate opening effect also explains the phase transition in ZIF-10 caused by CO2 molecules in our simulation, and can be applied to predict phase transitions in other materials with similar structure such as ZIF-7 and ZIF-8. The dynamics have also shown that the gas diffusion velocity is determined by the pore structure as well and by the accumulated layers of CO2 on the surface prior to being pushed in toward the centre of the material layer by layer. The de-absorption processes have also been studied in these materials by decreasing the pressure from 25 bar to 1 bar under at same temperature. The results indicate that the de-absorption is a reverse process of absorption. The structure of ZIF-10 went through a phase transition induced by CO2 recovered after the guest molecules had been released. The de-absorption can be accelerated by increasing the temperature.

京都大学 / 新制・論文博士 / 博士(理学) / 乙第13478号 / 論理博第1578号 / 新制||理||1692(附属図書館) / (主査)教授 北川 宏, 教授 吉村 一良, 教授 竹腰 清乃理 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM

abstract: We report the synthesis of novel boronic acid-containing metal-organic frameworks (MOFs), which was synthesized via solvothermal synthesis of cobalt nitride with 3,5-Dicarboxyphenylboronic acid (3,5-DCPBC). Powder X-ray diffraction and BET surface area analysis have been used to verify the successful synthesis of this microporous material. We have also made the attempts of using zinc nitride and copper nitride as metal sources to synthesize the boronic acid-containing MOFs. However, the attempts were not successful. The possible reason is the existence of copper and zinc ions catalyzed the decomposition of 3,5-Dicarboxyphenylboronic acid, forming isophthalic acid. The ended product has been proved to be isophthalic acid crystals by the single crystal X-ray diffraction. The effects of solvents, reaction temperature, and added bases were investigated. The addition of triethylamine has been shown to tremendously improve the sample crystallinity by facilitating ligand deprotonation / Dissertation/Thesis / Masters Thesis Chemical Engineering 2014

Thesis advisor: Jeffery A. Byers / Thesis advisor: Chia-Kuang Tsung / Homogeneous catalysts are advantageous in selective catalysis due to the well-defined active site at the molecular level. The poor recyclability, bimolecular aggregation, and undesired poison resistance of homogeneous catalysts hinder further industrial application despite the controlled reaction pathway due to the homogeneous environment. On the other hand, heterogeneous catalysts are preferred in industry due to their high recyclability and high activity. Yet, poor selectivity due to undefined active sites is a drawback. The construction of a host-guest system where a molecular level catalyst is incorporated into the Metal-Organic Framework (MOF) provides a promising solution to bridge those two fields. This composite maintains the advantages of homogeneous and heterogeneous catalysts and overcomes the disadvantages. However, finding an incorporation method that is versatile with minimum synthetic modification of the host and guest remains one of the challenges. In the first part of this dissertation, a new concept called “aperture-opening encapsulation’’ is introduced for incorporating large and diverse guest molecules into MOFs without changing the identity of either the guest or MOF. The approach capitalizes on the existence of linker exchange reactions, which, as our kinetic studies show, proceed via competition between associative and dissociative exchange mechanisms. The second part describes how this method is applied to incorporate a molecular catalyst into the cavity of UiO-66 for the hydrogenation of carbon dioxide to formate, which is a useful application for energy related industry. The developed hybrid composite showed the ability to be recycled, showed no evidence of bimolecular catalyst decomposition, and was less prone to catalyst poisoning. These results demonstrate for the first time how the aperture-opening process resulting from linker dissociation in MOFs can be utilized as a strategy to synthesize host-guest materials useful for chemical catalysis. After the establishment of the hybrid catalyst, the last part of the dissertation describes our efforts into the investigation of mass transport in catalysis. The understanding of the interaction between the host-guest is beneficial for the development of biological analogs in the future. / Thesis (PhD) — Boston College, 2019. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Over the last 20 years, there has occurred an increase in the number, scope, and impact of nanomaterials projects. By leveraging the Surface Plasmon Resonance of metallic nanoparticles for labelling, sensing, and treatment, researchers have demonstrated the versatile utility of these nanomaterials in medicine. The literature provides evidence of use of simple, well-known chemistry for nanomaterials synthesis when the focus is new applications of nanomaterials. A case in point, is the synthesis of metallic nanoparticles, whereby HAuCl4, CuCl2, Cu(acac)2, and AgNO3 are typically employed as nanoparticle precursors. Unfortunately, the use of these precursors limits the number of applications available to these materials - particularly for AuNPs in medicine, where the byproducts of nanoparticle synthesis (most often surface-adsorbed reductants, toxic stabilizers, and growth directors) cause nanoparticles to fail clinical trials. Despite the several thousand publications detailing the advancements in nanoparticle therapeutics, as of 2017, there were only 50 FDA-approved nanoparticle formulations. Less than 10 were based on metallic nanoparticles. This is a problem because many of these nanoparticle therapeutics demonstrate potent cell killing ability and labeling of cells. A solution to this problem may be the use of weakly coordinated, monovalent metal complexes, which require only one electron to reduce them to their metallic state. Further, by designing nanoparticle syntheses around these monovalent complexes, we can employ weaker, environmentally friendly stabilizers. This strategy also forgoes the use of exogenous reducing agents, because the monovalent complexes can be reduced and stabilized by one reagent. Herein we investigate the use of Au(Me2S)Cl, [Cu(MeCN)4]BF4, and AgBF4 with green stabilizers to synthesize a variety of nanomaterials. We find that a range of sizes of spherical particles, as well as a range of sizes of gold triangular prisms can be synthesized by using techniques that follow this strategy.

Metal organic frameworks (MOFs) are nanoporous materials composed of inorganic and organic structural building units (SBUs). Over the last several decades, interest in MOFs has grown considerably partially due to their promising capabilities for carbon capture and storage (CCS) technologies. This is mostly due to their tunable pore chemistry, high internal surface area and unique structural diversity. This thesis focuses on computational methods that were used to analyze and organize a database of hypothetical structures to facilitate MOF discovery. The work done is detailed in two main parts. In the first part of the thesis, a topologically diverse hypothetical MOF database, containing over 300,000 structures, is screened using simplified molecular-input line-entry system (SMILES) strings to identify SBUs in each structure. The structures in the database are then renamed according to the SBUs identified by the SMILES strings algorithm. The renaming of the structures allows users to have a good idea of the geometrical and topological distribution of the database. Furthermore, a quick and reliable test is developed to identify structures with incorrect bonding patterns/missing hydrogen. In the second part of the thesis, density functional theory (DFT) - derived charges are generated for each structure in the hypothetical MOF database. Using these charges, the CO₂/N₂ selectivity is calculated and compared with the selectivity values obtained from another charge generating method, split-charge equilibration (SQE), and it is determined that there is good agreement, r = 0.96, between the two methods. A machine learning model is then developed to identify relationships between geometrical features and CO₂/N₂ selectivity.

Over the past few decades, vast majority of industrial and academic research throughout the world has witnessed the emergence of materials that can serve as ideal candidates for potential utility in desired applications, and these materials are known as Metal Organic Framework (MOFs). This exceptional new family of porous materials is fabricated by linkage of metal ions or clusters and organic linkers via strong bonds. MOFs have been awarded with remarkable interest and widely studied due to their inherent structural methodology (e.g. use of various metals, expanded library of organic building blocks with different geometry and functionality particularly frameworks designed from carboxylate organic linkers) and unquestionably unique structural and chemical features for many practical applications. (i.e. gas storage/separation, catalysis, drug delivery etc). Simply, metal organic frameworks epitomize the beauty of porous chemical structures. From a design perspective, the introduction of the Molecular Building Block (MBB) approach is actively being pursued pathway by researchers toward the construction of MOFs by employing inorganic building blocks and organic linkers and taking advantage of not only their multiple coordination modes and geometries but also the way in which they are reticulated to generate final framework. In this thesis, research studies will be directed toward (i) the investigation of the relationship between experimental parameters and synthesis of well-known fcu –MOF, (ii) rational design and synthesis of new rare earth (RE) based MOFs, (ii) isoreticular materials based on particular MBB ([M3O(RCO2)6]), M= p-and d-block metals, and (iv) zeolite- like metal organic framework assembled from single-metal ion based MBB ([MN2(CO2)4]) via 2-, 3-,and 4-connected organic linkers. Consequently, the porosity, chemical and thermal stability, and gas sorption properties will be evaluated and detailed.

Les polymères de coordination (PC) présentent un intérêt tant fondamental qu'appliqué de par leur structure et composition modulables ouvrant de nouvelles perspectives au niveau des propriétés chimiques (catalyse, conversion matériaux mous-durs…) et physiques (magnétisme, optique…). L'objectif principal de ces études consiste à vérifier le transfert de la structure, méso-structure et composition du PC vers la céramique obtenue par traitement thermique. Dans ce contexte, ce manuscrit décrit des études sur la conversion de polymères de coordination obtenus à partir d'un auto-assemblage entre des métaux 4f, 5f et de la 2,5-dihydroxy-1,4-benzoquinone (DHBQ). Dans un premier temps, des méthodes de synthèses, aqueuse et anhydre en atmosphère contrôlée, ont été mises au point. Ainsi, plusieurs types de PC ont été obtenus (4f, 4f-4f, 4f-5f), les composés mixtes formant des solutions solides. Après caractérisation de ces composés, leur comportement sous traitement thermique a été étudié. Les principaux résultats montrent que les précurseurs à base de DHBQ obtenus par voie aqueuse possèdent une méso-structure micrométrique, formée par l'assemblage de sous-unités monocristallines possédant la même structure cristallographique quelle que soit la morphologie observée. L'étude de l'assemblage de cette méso-structure a permis de contrôler la morphologie du grain élémentaire (cylindre, cube, disque…) avec une très bonne distribution en taille. La mise en œuvre de systèmes anhydres en atmosphère contrôlée a permis d'accéder à une plus large gamme de paramètres micro-structuraux (surface spécifique, porosité…). Pour l'ensemble des composés de type PC, la conversion thermique en céramique n'a pratiquement pas altéré la morphologie des matériaux. Les aspects microstructuraux ont pu être contrôlés via la méthode de synthèse. / Coordination polymers (CP) are of great academic and industrial interest due to flexible structure and composition and offer prospects for original chemical (catalysis, soft-hard materials conversion…) and physical properties (magnetism, optics…). The major interest of these studies is to check the transfer of the structure, meso-structure and composition from the CP to the ceramic via a thermal treatment. In this context, this thesis describes studies on conversion of coordination polymers obtained by self-assembly of 4f and 5f metal ions with 2,5-dihydroxy-1,4-benzoquinone (DHBQ). Aqueous and anhydrous synthetic ways were developed, which yielded different kinds of CPs (4f, 4f-4f, 4f-5f) ; solid solutions were obtained with the mixed compounds. The products were characterized and their behaviour under thermal treatment was studied. The main results show that the DHBQ-based precursors obtained by aqueous way have a micrometric meso-structure, formed by the assembly of micro-crystalline subunits which all posses the same crystallographic structure. The study of the assembly of the meso-structure allowed controlling the morphology of the elementary grain (cylinder, cube, disk ...) with very good size distribution. The implementation of anhydrous systems in a controlled atmosphere allowed yielded a wider range of micro-structural parameters (surface area, porosity ...). For all CP-type compounds, the thermal conversion to ceramic has barely altered the morphology of the materials. The microstructural aspects could be controlled via the method of synthesis.