A new group of nanoporous materials, metal organic frameworks (MOFs), have emerged as a fascinating alternative to more traditional nanoporous materials for membrane based gas separations. Although hundreds of different MOF structures have been synthesized in powder forms, very little is currently known about the potential performance of MOFs as membranes since fabrication and testing of membranes from new materials require a large amount of time and resources. The purpose of this thesis is to predict the macroscopic flux of multi-component gas mixtures through MOF-based membranes with information obtained from detailed atomistic simulations. First, atomically detailed simulations of gas adsorption and diffusion in MOFs combined with a continuum description of a membrane are introduced to predict the performance of MOF membranes. These results are compared with the only available experimental data for a MOF membrane. An efficient approximate method based on limited information from molecular simulations to accelerate the modeling of MOF membranes is then introduced. The accuracy and computational efficiency of different modeling approaches are discussed. A robust screening strategy is proposed to screen numerous MOF materials to identify the ones with the high membrane selectivity and to direct experimental efforts to the most promising of many possible MOF materials. This study provides the first predictions of any kind about the potential of MOFs as membranes and demonstrates that using molecular modeling for this purpose can be a useful means of identifying the phenomena that control the performance of MOFs as membranes.

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have become the focus of intense study over the past decade due to their potential for advancing a variety of applications including air purification, gas storage, adsorption separations, catalysis, gas sensing, drug delivery, and so on. These materials have some distinct advantages over traditional porous materials such as the well-defined structures, uniform pore sizes, chemically functionalized sorption sites, and potential for post-synthetic modification, etc. Thus, synthesis and adsorption studies of porous MOFs have increased substantially in recent years. Among various prospective applications, air purification is one of the most immediate concerns, which has urgent requirements to improve current nuclear, biological, and chemical (NBC) filters involving commercial and military purposes. Thus, the major goal of this funded project is to search, synthesize, and test these novel hybrid porous materials for adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), and to install the benchmark for new-generation NBC filters. The objective of this study is three-fold: (i) Advance our understanding of coordination chemistry by synthesizing novel MOFs and characterizing these porous coordination polymers; (ii) Evaluate porous MOF materials for gas-adsorption applications including CO2 capture, CH4 storage, other light gas adsorption and separations, and examine the chemical and physical properties of these solid adsorbents including thermal stability and heat capacity of MOFs; (iii) Evaluate porous MOF materials for next-generation NBC filter media by adsorption breakthrough measurements of TICs on MOFs, and advance our understanding about structure-property relationships of these novel adsorbents.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 168-180).

Metal-Organic Materials (MOMs) represent an important class of solid-state crystalline materials. Their countless attractive attributes make them uniquely suited to potentially resolve many present and future utilitarian societal challenges ranging from energy and the environment, all the way to include biology and medicine. Since the birth of coordination chemistry, the self-assembly of organic molecules with metal ions has produced a plethora of simple and complex architectures, many of which possess diverse pore and channel systems in a periodic array. In its infancy however this field was primarily fueled by burgeoning serendipitous discoveries, with no regard to a rational design approach to synthesis. In the late 1980s, the field was transformed when the potential for design was introduced through the seminal studies conducted by Hoskins and Robson who transcended the pivotal works of Wells into the experimental regime. The construction of MOMs using metal-ligand directed assembly is often regarded as the origin of the molecular building block (MBB) approach, a rational design strategy that focuses on the self-assembly of pre-designed MBBs having desired shapes and geometries to generate structures with intended topologies by exploiting the diverse coordination modes and geometries afforded by metal ions and organic molecules. The evolution of the MBB approach has witnessed tremendous breakthroughs in terms of scale and porosity by simply replacing single metal ions with more rigid inorganic metal clusters whilst preserving the inherent modularity and essential geometrical attributes needed to construct target networks for desired applications. The work presented in this dissertation focuses upon the rational design and synthesis of a diverse collection of open frameworks constructed from pre-fabricated rigid inorganic MBBs (i.e. [M(CO2)4], [M2(RCO2)4], [M3O(RCO2)6], MN3O3, etc), supermolecular building blocks (SBBs) and 3-, 4- and 6-connected organic MBBs. A systematic evaluation concerning the effect of various structural parameters (i.e. pore size and shape, metal ion, charge, etc) on hydrogen uptake and the relative binding affinity of H2-MOF interactions for selected systems is provided.

Metal--organic frameworks (MOFs) are porous crystalline materials that are synthesized from rigid organic ligands and metal-containing clusters. They are highly tunable as a number of different structures can be made by simply changing the organic ligand and/or metal ion. MOFs are a promising class of materials for many energy-related applications, including H2 storage and CO2 capture and sequestration. Computational studies can provide insights into MOFs and the mechanism of gas sorption and separation. Theoretical studies on existing MOFs are performed to determine what structural characteristics leads to favorable gas sorption mechanisms. The results from these studies can provide insights into designing new MOFs that are tailored for specific applications. In this work, grand canonical Monte Carlo (GCMC) simulations were performed in various MOFs to understand the gas sorption mechanisms and identify the favorable sorption sites in the respective materials. Experimental observables such as sorption isotherms and associated isosteric heat of adsorption, Qst, values can be generated using this method. Outstanding agreement with experimental measurements engenders confidence in a variety of molecular level predictions. Explicit many-body polarization effects were shown to be important for the modeling of gas sorption in highly charged/polar MOFs that contain open-metal sites. Indeed, this was demonstrated through a series of simulation studies in various MOFs with rht topology that contain such sites. Specifically, the inclusion of many-body polarization interactions was essential to reproduce the experimentally observed sorption isotherms and Qst values and capture the binding of sorbate molecules onto the open-metal sites in these MOFs. This work also presents computational studies on a family of pillared square grid that are water-stable and display high CO2 sorption and selectivity. These MOFs are deemed promising for industrial applications and CO2 separations. Simulations in these materials revealed favorable interactions between the CO2 molecules and the SiF62- pillars. Further, the compound with the smallest pore size exhibits the highest selectivity for CO2 as demonstrated through both experimental and theoretical studies. Many other MOFs with intriguing sorption properties are investigated in this work and their sorption mechanisms have been discerned through molecular simulation.

A novel Poly (methyl methacrylate) Composites using Copper-4, 4'- Trimethylenedipyridine Metal-Organic Framework as Fillers (CTMOF) had been synthesized and analyzed. The CTMOF structure had been characterized by X-ray crystallography. The thermal and mechanical properties of CTMOF-PMMA composites had been examined via optical microscopy, differential scanning calorimetry (DSC), microhardness, and dynamic mechanical thermal analysis (DMTA). The results showed the increase of Glass transition temperatures and the improvement of mechanical properties of the PMMA composites as the concentration of CBMOF loading increased.

Metal-organic frameworks (MOFs) are a relatively new class of porous materials, assembled from inorganic metal nodes and organic ligands. MOFs have garnered significant attention in the porous materials and adsorption fields in recent years due to their various attractive features such as high surface areas and pore volumes, tunable and uniform pore sizes, chemically functionalized adsorption sites, and potential for post-synthetic modification. These features give MOFs enormous potential for use in applications such as air purification, methane and hydrogen storage, separations, catalysis, sensing, and drug delivery. Therefore, synthesis and adsorption studies of MOFs have increased tremendously in recent years. Among the aforesaid applications, air purification and air quality control are important topics because existing porous media are ineffective at the adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents. Thus, there is a critical need for radical improvements in these purification systems. MOFs have shown great potential to become next-generation filter media as they outperform the traditional porous materials such as activated carbons and zeolites in the air purification of TICs such as ammonia and sulfur dioxide. In spite of the numerous desirable attributes of MOFs, the practical use of these new materials in most applications hinges on their stability in humid or aqueous environments. The sensitivity of certain MOFs under humid conditions is well known, but systematic studies of the water stability properties of MOFs are lacking. This information is critical for identifying structural factors that are important for development of next-generation, water stable MOFs. In addition to the water stability issue, difficulty in the scale up of MOF synthesis has also plagued MOFs. Hence, the goal of this Ph.D. dissertation research is to design ammonia-selective, water stable MOFs that can be synthesized on a large scale. This work will have a direct impact on moving the MOF field forward to the commercial level. To achieve the aforementioned goal, this Ph.D. dissertation research has been divided into following three objectives: (1) Advance our understanding of the water stability of MOFs and develop design criteria for the construction of water stable MOFs. (2) Design water stable, ammonia-selective MOFs for next-generation chemical, biological, radiological, and nuclear (CBRN) filter media. (3) Investigate the scale-up of the UiO-66 MOF scaffold. Through the research efforts over the past four years, it is discovered that it is possible to adjust the water stability of pillared MOFs in both positive and negative directions by proper shielding of the ligand via functional groups. This study is the first of its kind and is of high value for the MOF community. This shielding concept is further extended by synthesizing 4 novel isostructural MOFs with methyl functional groups at different positions on the ligand. For the first time, light is shed on the important distinction between kinetic and thermodynamic water stability and experimental evidence for a kinetically governed water stability mechanism in these MOFs is provided. It is also demonstrated that, using catenation in combination with a pillaring strategy, it is possible to obtain water stable MOFs even when the pillar ligand has lower basicity (pKa value). Ammonia breakthrough measurements have shown that a hydroxyl functionalized Zr-based UiO-66 material is promising as it could offer a method for targeting the removal of specific chemical threats in a chemically stable framework that does not degrade in the presence of water. Large scale synthesis of a water stable MOF, UiO-66, is studied using glass vials and Teflon lined autoclaves. UiO-66 synthesis methods have been refined such that it is now possible to produce more than 70 times the yield obtained from the original synthesis report using the same reaction volume. This would result in a significant reduction of the MOF production cost at the industrial scale. Methane and hydrogen are ‘clean fuels’ (less CO2 emissions than petroleum) and MOFs are being tested for their on-board storage in cars due to the extremely high storage capacities of MOFs being promising enough to meet the requirements. Hence, more broadly, this Ph.D. dissertation work will lead to commercial applications of MOFs, which can revolutionize a variety of gas separation and storage problems such as CO2 capture, natural gas upgrading, and methane and hydrogen storage for clean fuel technologies. This would greatly reduce the environmental concerns faced by our society today.

Nanoporous molecular sieve materials like metal organic frameworks (MOFs) and metal oxide nanotubes (AlSiNTs) have found a wide range of technological applications in catalysis, separations, and ion exchange due to their salient features over other contemporary sensing materials. As a result, these materials can function as a chemical recognition layer that relies on analyte adsorption and they have shown to selectively adsorb specific gas molecules from mixtures. The characterization of gas adsorption in these materials is performed predominantly by commercial gravimetric equipment, whose capital and operating costs are generally high and require relatively large amounts of sample. Thus, it is desirable to obtain a reliable measure of the gas transport properties of these materials over a substantial range of pressure and temperature by non-gravimetric methods. The objective of this thesis is to investigate the adsorption and diffusion characteristics of recently-identified nanoporous materials through the development and use of a high-pressure/high-temperature quartz crystal microbalance (QCM) device. In this regard, this thesis is divided into four main objectives, viz. (1) Design and development of high temperature/ high pressure QCM device, (2) Measurement and analysis of adsorption characteristics in nanoporous materials, (3) Diffusion measurement and analysis in polymer thin films and (4) Diffusion measurement and analysis in MOF crystals. The results obtained in Objectives 2-4 will allow us to make important recommendations regarding the use of specific nanoporous materials in molecular separation applications and also lead to significant understanding of gas uptake thermodynamics in nanoporous materials via the application of analytical models to the experimental data.

Les Metal-Organic Frameworks résultent de l'organisation de clusters métalliques et demolécules organiques chélatantes qui forment un réseau cristallin poreux. Leur découverte apermis des avancées majeures dans le domaine du stockage et de la séparation des gaz.Malheureusement la faible stabilité et l'acidité modérée de ces matériaux ne les rendent quepeu compétitifs par rapport aux zéolites dans le domaine du raffinage ou de la dépollution. Ils'agit d'explorer, avec ces matériaux, de nouvelles applications catalytiques en tirant partie deleur principale qualité : leur modularité. En effet le large choix de métaux, de ligands, ainsique la post fonctionnalisation de ces derniers permet la synthèse contrôlée de matériauxpossédant des propriétés de flexibilité, de confinement ainsi qu'un environnement chimiquesimilaire à celui des sites actifs des enzymes. Ce travail s'inspire du procédé catalytique desenzymes pour obtenir des MOFs hautement sélectifs en conditions douces. Nous décrivons ledéveloppement de méthodes pour encapsuler des catalyseurs organométalliques dans despores calibrés afin de modifier la sélectivité d'une réaction d'oxydation et stabiliser lecatalyseur. Quatre MOFs supportant des groupes amino ont été synthétisés afin de permettreleur post fonctionnalisation. Les propriétés de flexibilité ainsi que la distribution des sitespotentiellement actifs du MOF MIL-53 ont également été contrôlés grâce à lafonctionnalisation partielle de la structure. Enfin ces amino MOFs furent post fonctionnalisésen isocyanate en deux étapes afin d'améliorer la réactivité de la structure et de permettre legreffage de diverses amines. Ces outils pourraient permettre à court terme la conception deMOFs dont les pores ont un environnement semblable aux metalloenzymes.

Advances in flexible and functional metal–organic frameworks (MOFs), also called soft porous crystals, are reviewed by covering the literature of the five years period 2009–2013 with reference to the early pertinent work since the late 1990s. Flexible MOFs combine the crystalline order of the underlying coordination network with cooperative structural transformability. These materials can respond to physical and chemical stimuli of various kinds in a tunable fashion by molecular design, which does not exist for other known solid-state materials. Among the fascinating properties are so-called breathing and swelling phenomena as a function of host–guest interactions. Phase transitions are triggered by guest adsorption/desorption, photochemical, thermal, and mechanical stimuli. Other important flexible properties of MOFs, such as linker rotation and sub-net sliding, which are not necessarily accompanied by crystallographic phase transitions, are briefly mentioned as well. Emphasis is given on reviewing the recent progress in application of in situ characterization techniques and the results of theoretical approaches to characterize and understand the breathing mechanisms and phase transitions. The flexible MOF systems, which are discussed, are categorized by the type of metal-nodes involved and how their coordination chemistry with the linker molecules controls the framework dynamics. Aspects of tailoring the flexible and responsive properties by the mixed component solid-solution concept are included, and as well examples of possible applications of flexible metal–organic frameworks for separation, catalysis, sensing, and biomedicine.