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Single-ion magnets (SIMs) are at the forefront of molecular electronic spin magnets with potential applications in magnetic memory storage devices. However, the magnetic properties of the SIMs are yet to be completely understood, especially the magnetic properties of large anisotropy systems. A part of this dissertation is to utilize optical and neutron spectroscopies such as far-IR magneto-spectroscopy (FIRMS) and inelastic neutron scattering (INS) to quantify the anisotropy and study the phonon properties of the SIMs as two-dimensional (2-D) metal-organic frameworks (MOFs) or coordination polymer (CP), and a molecular magnet. In addition, ab initio calculations are used to understand the origin of the anisotropy and the electronic structure of the systems. Furthermore, the systems studied in this dissertation can also be quantum bit (qubit) candidates. Qubits are the building blocks of quantum computers. The properties of qubits can be determined using pulsed electron paramagnetic resonance (pulsed EPR). The results yielded the spin-lattice relaxation time and the spin-spin relaxation time, where both relaxation times are crucial in determining the effectiveness of the qubit candidates. The second part of this dissertation focuses on studying the symmetry-protected topological states of a Haldane one-dimensional (1-D) spin-1 chain as a 2-D MOF. The topological properties of the Haldane spin-1 chain can be highlighted by the Haldane energy gap that exists between the non-magnetic singlet ground state and the triplet excited state, the fractionalized edge states, and the system’s robustness to external perturbations through symmetry-protection. Optical and neutron spectroscopies in addition to the magnetic susceptibility measurements were used to quantify the energy gaps as well as the anisotropy that governs the system. Furthermore, the spin chain is found to exhibit a critical field and critical temperature where the system observes a phase transition. These studies in this dissertation, in part, aim to give a complete understanding of the magnetic anisotropy and phonon properties of the SIM and qubit systems as well as to have a comprehensive understanding of the topological properties of the Haldane 1-D spin-1 chain system.

Herein, density functional theory (DFT) was used for optimizing the geometry of proposed intermediates, built using Spartan Student, in the synthesis of the indium infinite-chain secondary building unit. Dimeric indium species with similar backbones were proposed for each system as a representative of the indium infinite-chain secondary building unit. By calculating the enthalpies of formation for intermediates created from InCl3(H2O) and In(NO3)3(H2O), similar and contrasting enthalpic trends between systems and individually proposed mechanisms were found and compared. All systems consist of motifs 1, 2, 3a, and 3b, which attempt to describe similar mechanistic routes from starting material to proposed dimer. The deprotonation of water before and after becoming a µ2 bridge with respect to two indium atoms was compared among systems, and the most enthalpically favorable bridge to form first (hydroxyl or carboxylate) in the synthesis of the indium infinite-chain secondary building unit was examined. After analyzing the results, they support the possibility that there may be multiple enthalpically reasonable methods of self-assembly and repair.

Describing the relations and interactions between various entities, networks are critical in mathematics, biology, computer science, social sciences, and business. In materials chemistry, a network refers to a system where directional interactions spatially connect distinct molecular units. Fascinatingly, an underlying network is not unique to ordered crystalline structures. Various melts and glasses adopt network structures, which fundamentally dictates their macroscopic properties and wide-ranging functionalities. In comparison to conventional disordered networks such as glassy SiO2, metal–organic network-forming liquids and glasses contains metal centers bridged by organic ligands instead of a single oxygen anion. The ability to manipulate the directional interactions between metal centers by modifying the functional group, size, and shape of the ligand offers great potential to significantly expand the design space of functional disordered materials with unique network topologies and properties. The work presented in this dissertation describes the design, synthesis, and characterization of a novel class of network-forming liquids and glasses through realizing melting transitions in metal–organic networks at record-low temperatures. Chapter One provides an introduction to metal–organic liquids and glasses as a new class of network-forming materials, with a particular focus on the interconversion between the crystalline, molten, and glassy phases of metal–organic networks. In Chapter Two, efforts to establish general thermodynamics principle to promote reversible, low-temperature melting by decreasing the enthalpy and increasing the entropy of fusion in a series of metal–bis(acetamide) networks are discussed. The network-forming nature of a metal–bis(acetamide) liquid is supported by preserved metal–ligand coordination bonds and extended-range structural ordering, as characterized by extended X-ray fine structure (EXAFS) and pair distribution function (PDF), respectively. In addition, differences in the glass-forming ability of the metal–bis(acetamide) liquid are observed and rationalized through rheological measurements. In Chapter Three, the network-forming nature of metal–bis(acetamide) liquids is further illustrated through a comparative study with molecular metal–acetamide liquids. Despite sharing similar metal–ligand coordination environments, metal–bis(acetamide) liquids exhibit structural ordering on a much longer length scale and significantly higher viscosities relative to their molecular analogs, which contributes to the higher glass-forming ability of the former. Chapter Four describes facile reversible recrystallization and glass transitions in a series of metal–ethylenebis(acetamide) networks. The high tunability of the structure and thermophysical properties of these materials are then demonstrated, either by synthetic modification or by liquid-phase blending to form binary glasses. Notably, a large reflectivity contrast ratio of 4.8 between the glass and crystalline phases of a Co−ethylenebis(acetamide) binary network is demonstrated, which has exciting implications for optical switching and rewritable data storage. Chapter Five discusses melting and glass formation in porous metal–bis(acetamide) frameworks bearing a semi-rigid ligand. While structural transitions and loss of porosity occur concurrently with melting, CO2 pressure and pressure history is found to substantially impact their glass transition behavior, revealing exciting opportunities for using a gas medium to condition structures of metal–organic glasses without changing their compositions.

As respiratory illness infections and related environmental antagonisms continue to beleaguer our contemporary moment, the construction of low-cost, scalable, highly sensitive, remarkably selective, ultralow power, and user-friendly technologies for detecting hazardous chemical species indoors remains imperative. Namely, the accumulation of carbon dioxide (CO2) and select volatile organic compounds (VOCs) in indoor settings is associated with deleterious human health conditions, such as fatigue, headaches, and irritation of the throat. While commercialized indoor gas detectors exhibit desirable analyte sensitivity and long-term sensing endurance, these devices characteristically suffer from cost, bulk, and power requirements. Toward addressing these limitations, this work introduces amine-functionalized, dye-loaded metal-organic framework (MOF)-based chemical sensors whose color change upon exposure to indoor analytes produces a more passive, smaller, cheaper, and simpler alternative to existing technologies. In this dissertation, the iterative synthesis and spectroscopic characterization of color-based, MOF-based indoor analyte sensors are accomplished toward the realization of an ideal sensor for an improved indoor air quality monitoring. Chapter 1 situates the relationship among indoor CO2 and indoor VOCs in the ongoing Coronavirus disease 2019 (COVID-19) pandemic, illustrating the range of detrimental realities for human and environmental health. To best articulate the stakes of structured public health violence, the chapter engages an interdisciplinary analysis of power in which antiblack worldbuilding is linked to previous, present, and emerging environmental violence and human unwellness. Once certain predatory formations are more concretely assigned answerability for air-based violence, the chapter closes with attendant scientific interventions and provides the rationale for the development of color-based chemical sensors to preempt adverse exposures to indoor analytes. Chapter 2 introduces a first-generation colorimetric gas sensor composed of a MOF, primary amine, dye, and methanol blended, drop-cast on cellulose filter paper, and exposed to indoor levels of CO2 (700 parts per million, ppm, and up). Here, the pristine MOF—the zeolitic imidazolate framework-8 (ZIF-8) consisting of zinc (Zn2+) cations tetrahedrally coordinated by 2-methylimidazolate (Hmim¬-) organic linkers—serves as the highly-porous adsorbent with known physisorptive affinity to CO¬2. Following its unstirred, room temperature synthesis, ZIF-8 is blended with the primary amine, ethylenediamine (ED), and the dye, phenolsulfonpthalein (PSP, or phenol red). The capacity of the resulting sensor, termed PSP-ED/ZIF-8, to effectively function in plausible indoor air conditions is probed via several characterization techniques. Powder X-ray diffraction (PXRD) is used to demonstrate the long-term chemical stability of ZIF-8 in the basic environment created from the addition of ethylenediamine. Moreover, scanning electron microscopy (SEM) is used to define the morphological properties of PSP-ED/ZIF-8 in relation to the molar ratio of the ZIF-8 metal : ZIF-8 linker : methanolic solvent precursors, as well as the post-synthetically incorporated colorimetric ingredients. A LabView-enabled gas dosing apparatus (coupled with a nondispersive infrared, NDIR, gas sensor to substantiate gas levels, humidity, and temperature) is implemented to deliver a range of CO2 levels (700-7,500 ppm) under various humidity (0-80% RH) at room temperature to PSP-ED/ZIF-8 drop-cast on cellulose filter paper. Through smartphone video recording, qualitative assays of gas-exposed PSP-ED/ZIF-8 are collected, with an increasing intensity of the fuchsia-to-yellow color change observed with increased concentrations of CO2. In realizing that the perceived color change is only permissible in the presence of the MOF, Brunaeur-Emmett-Teller (BET) surface area analysis is performed to evaluate the role of high surface area on ZIF-8’s ability to accommodate both ethylenediamine and phenol red, as well as provide sorption sites for indoor CO2. Finally, an ex-situ ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopic technique is achieved to quantify how the Kubelka-Munk, F(R), values at 443 and 570 nm resonant with phenol red change relative to each other as the concentration of CO2 and humidity levels are modified. Despite immediate and increasing responses of PSP-ED/ZIF-8 to 700 ppm CO2 (and up) in dry environment, qualitative color assays and quantitative UV-Vis measurements exhibit a largely suppressed color change in the presence of humidity. To improve the colorimetric gas response across humidity, a revised sensor recipe is accomplished. In Chapter 3, an enhanced colorimetric indoor CO2 sensor is attained through the direct incorporation of phenol red into the ZIF-8 metal and linker precursor broth. The orange crystals formed, PSP:ZIF-8, are then blended with ethylenediamine to form a second-generation sensor, ED/PSP:ZIF-8. Collected PXRD patterns, as well as Fourier transform infrared (FTIR) spectroscopic transmittance scans, confirm the structural integrity of ZIF-8 in both PSP:ZIF-8 and ED/PSP:ZIF-8. In addition, SEM and transmission electron microscopy (TEM) demonstrate the fourfold increase in size of ZIF-8 crystals upon growth in a phenol red-loaded methanolic precursor mixture (compared to the PSP-ED/ZIF-8 first generation chemical sensor). Reimplementation of the LabView-based gas apparatus demonstrate a significantly more intense fuchsia-to-yellow color change of the ED/PSP:ZIF-8 sensor than the PSP-ED/ZIF-8 sensor upon exposure to indoor CO2 levels (600 ppm and up) across humidity (0-80% RH). To better elucidate these assays, the smartphone-gathered images are read into a MATLAB script and decomposed into their respective red-, green-, and blue (RGB) distributions, which both confirms a stronger color change in the second-generation sensor and enables a reasonable approach with which to index color change data for the optimal indoor gas sensor. In addition to this approach, an in-situ UV-Vis diffuse reflectance spectroscopic technique is developed in which room-temperature Kubelka-Munk spectra at 443 and 570 nm are directly collected as indoor levels of CO2 are exposed to both first- and second-generation sensors across humidity, as well as in the presence of VOCs (acetone). Consistent with the qualitative assays, ED/PSP:ZIF-8 exhibits a stronger color change than the first-generation sensor in dry CO2, CO2 and VOC environment, and humid CO2. However, compared to its dry CO2 and CO2+VOC colorimetric response, ED/PSP:ZIF-8 still displays a noticeably suppressed color change at heightened humidity. To initially determine differences in the sensing performance of the first- and second-generation sensors, washing studies are conducted in which both sensors are successively washed with methanol. Upon collecting FTIR spectroscopic scans with each wash, the nitrogen-hydrogen (N-H) stretching vibrations indicative of ethylenediamine disappear in both sensors, which suggests the localization of ethylenediamine to the external surface of ZIF-8 in both sensors. Similarly, in a second washing experiment, both sensors are washed with methanol and replenished with (i) fresh methanol, (ii) fresh methanol and ethylenediamine, and (iii) fresh methanol, ethylenediamine, and phenol red. Upon being replenished in these three ways, both sensors are exposed to dry CO2. Neither sensor responds to CO2 upon sole replenishment in methanol, which reaffirms the probable location of ethylenediamine to the external surface area of ZIF-8. However, when both sensors are washed and replenished with an ethylenediamine methanolic solution, only the ED/PSP:ZIF-8 sensor recovers its original color change (whereas the PSP-ED/ZIF-8 sensor does not). Once both phenol red and ethylenediamine replenish the sensor (in methanol), the PSP-ED/ZIF-8 partially recovers its colorimetric gas response from its fresh state. These observations imply that phenol red is located on the external surface of ZIF-8 in the first-generation sensor (but inside the internal pore cavities in the second-generation sensor). Given the unresolved hypothesis of phenol red location between both sensors (as well as how phenol red binds to ZIF-8 in general and the underlying chemical sensing mechanism informing the color change), mechanistic studies are pursued. Chapter 4 details an exhaustive set of spectroscopic analyses used to (i) distinguish the first- and second-generation colorimetric gas sensors and (ii) examine the role of surface basicity (or inclusion of ethylenediamine) on the thermodynamics of phenol red adsorption to ZIF-8 for colorimetric indoor analyte monitoring. The first half of this chapter involves the use of carbon, hydrogen, nitrogen, and sulfur (CHNS) elemental analysis to discern how much phenol red adsorbs to ZIF-8 between the first- and second-generation sensors. A gas-dosed FTIR spectroscopy is later implemented to investigate the physisorptive and chemisorptive nature of ZIF-8 and ethylenediamine-modified ZIF-8 exposure to dry CO2. The second half of this chapter uses a liquid-phase UV-Vis spectroscopy to distinguish the adsorption isotherms of room temperature phenol red adsorption onto ZIF-8 (with and without ethylenediamine). In addition, FTIR spectroscopy is implemented to discern whether the presence of ethylenediamine controls how phenol red binds to the ZIF-8 adsorbent. This chapter concludes with an introduction of second-harmonic spectroscopic techniques to evaluate the Gibbs free energy of adsorption (ΔGADS) of phenol red to ZIF-8 (with and without ethylenediamine) to illustrate how the components of the “full” colorimetric gas sensor interact to bind indoor CO2. In addition, X-ray photoelectron spectroscopy (XPS) is briefly discussed toward evaluating MOF/dye/amine interactions. Once the internal workings of the previous sensors are elaborated, Chapter 5 describes a third-generation sensor prepared from the admixture of ZIF-8 species crystallized from precursor solutions blended with different dyes. Specifically, a universal pH indicator (mixed with phenol red) produces an improved sensor with a strong colorimetric CO2 response in low and intermediate humidity. To simulate indoor air conditions more closely, this sensor is exposed to CO2, humidity, and acetone, and its response is quantified via an in-situ UV-Vis diffuse reflectance spectroscopy. Chapter 6 completes the dissertation with a summary of key results and recommends future studies involving multi-color, multi-transduction MOF-based analyte sensing. This work presents a novel, proof-of-concept colorimetric sensor whose optimization and characterization are accomplished through coupled spectroscopies toward the eventual creation of an ideal indoor analyte sensor for widespread use.

The porous materials discussed in this dissertation are metal-organic frameworks (MOFs) and porous liquids. Due to their high surface areas, tunable structures, and controllable porosities, MOFs have been explored for a wide variety of drug delivery applications. In chapter 2, MOFs have been used as magnetothermal-triggered release carriers through spatially distributed iron oxide nanoparticles within MOF matrix as a magnetic heating mediator and surface-grafted thermal-responsive nanocap as an alternating magnetic field (AMF)-responsive gatekeepers, achieving monitoring of drug release via external AMF by a conformational change of nanocap. In chapter 3, MOF, as a non-toxic loading carrier, encapsulate naringin, a natural product to serve as a multifunctional bio-platform capable of treating Gram-positive bacteria and certain cancers by slowly and progressively releasing the encapsulated naringin as well as improving and modulating immune system functions through the synergies between naringin and MOF. In chapter 4, porous liquid with unique solvent-free fluidity properties as a drug delivery platform for the first time. The interaction between hollow silica nanoparticle and polymerized ionic liquid, followed by ionic grafting brush of poly (ethylene glycol) telomer, makes this designed porous liquid responsible for high drug-loading and pH-responsive drug-releasing abilities along with slow degradation behavior. In addition to their high loading and controlled release, In vitro cell viability and cell uptake are also studied, thus opening up new opportunities for long-term chemotherapy.

Metal-organic frameworks or MOFs are an extremely useful tool in many areas of applications. Their popularity in recent years has arisen from their high efficiency in catalytic chemical reactions. This is made possible due to their porous interior and the ability of the MOFs components to be functionalized. These same traits make MOFs excellent for use in protein encapsulation or immobilization and have the potential to become excellent drug carriers. Their development in this utilization has been limited dramatically compared to MOFs chemical applications. This is due in part to the nature of biological processes taking longer to study, but it is also in part due to a lack of understanding in how biological materials interact with these nanoparticles. In order for the development of biological applications with MOFs to continue, these interactions must be further understood through research. In this compilation of our work, we seek to push the boundaries of conventional understanding in our field by studying the interaction between MOFs and biological materials such as proteins and drugs. In doing so, we report our findings and show that protein loading can possibly be improved, enzyme reactions can be improved outside of normal conditions, cell signaling proteins can be delivered successfully to cells and illicit a cellular response, and MOF particles can be effectively used as a delivery device to provide sustained and controlled release of both guest particles and drugs conjugated to the exterior of the MOF particle.

Abstract: Pressure and temperature swing adsorption processes are increasingly being designed and optimized computationally. The reliability of these predictions are highly dependent on the quality of the experimental equilibrium and kinetic data used in these simulations. Consistent experimental methodology is fundamental to obtain accurate data. The main aims of this thesis are to provide multicomponent adsorption equilibrium and kinetic data on various adsorbents, to provide recommendations to improve experimental methodology, and finally to use this data for pressure swing adsorption design and optimization. Dynamic column breakthrough is extensively studied in this thesis. This method involves a column packed with an adsorbent of interest that can measure multicomponent equilibrium and kinetics, as well as column dynamics. This thesis examines all three of these aspects in dynamic column breakthrough. A few highlights are described below. The equilibrium loading of each species in a multicomponent mixture can be calculated from a dynamic column breakthrough experiment. This is most commonly done with a ternary gas mixture for a binary equilibrium measurement: the column is initialized with an inert gas (such as helium), and then replaced with a binary mixture of adsorbates. After the experiment is finished, a transient mass balance can be solved to yield an equilibrium loading for each species in the mixture. However, a ternary adsorption breakthrough experiment (two adsorbates and one inert) on a highly selectively system, will often yield erroneous equilibrium data for the weaker component. This is in part due to the measurement of effluent flow, and part due to the long experimental times that accumulate error in the transient mass balance. It was found that a desorption breakthrough experiment, performed after a desired multicomponent adsorption experiment, yielded more accurate data with less associated error for the weaker species. This is due to the relatively short experimental time for the weaker component to desorb, minimizing the accumulation of error in the mass balance. The stronger component can be calculated from the adsorption breakthrough experiment. The combined elution profile yields the binary equilibrium data at a given composition, temperature and total pressure. The error associated with the adsorption mass balance of the weaker component can also be bypassed by performing true binary experiments without an inert (only the two adsorbates of interest). These experiments are performed by saturating the column with one adsorbate of interest, and then performing an adsorption breakthrough experiment with a binary mixed-adsorbate system. This methodology still requires two sets of experiments to obtain a single binary pairing, but avoids error due to roll-up. Dynamic column breakthrough is usually performed with tens to hundreds of grams of adsorbent. This sample size creates a large signal change in the effluent mole flow measurement, reduces loading variation from heterogeneous samples, and minimizes effects due to the extra-column volume. However, nothing in the transient mass balance excludes measurement on milligram sized samples. This thesis provides recommendations to build a milligram-scale dynamic column breakthrough apparatus to obtain accurate and precise unary and binary equilibrium data. While some aspects of milligram-scale experimentation are complicated, overall the milligram-scale operation offered many more benefits. These included shorter experimental times, near-isothermal operation, a much simpler effluent flow calibration, as well as being able to test as-synthesized and crystalline adsorbents. This apparatus was tested with mixtures of dry gases on various adsorbent materials. This thesis provides quantitative data for unary and binary adsorption equilibrium, and qualitative trends for multicomponent kinetics, from dynamic column breakthrough experiments on milligram quantities of adsorbent.

The development of controllable drug delivery systems is crucial for reducing toxicity and minimizing off-target drug effects for patients undergoing chemotherapy. Metal–organic frameworks (MOFs) are a class of hybrid materials that have become of interest in the field of drug delivery. MOFs are composed of metal nodes and organic bridging ligands. MOFs have a wide range of desirable properties including chemical stability, high porosity, and structural tunability which have positioned them as successful drug carriers. Through judicious choice of linker, stimuli-responsive MOFs can be synthesized to achieve precise control over cargo release. Previously, our lab developed a novel light-responsive drug delivery system using a framework known as UiO-AZB (UiO= University of Oslo, AZB=4,4ʹ-azobenzenedicarboxylic acid). This MOF contains a photoswitchable azobenzene linker. Upon irradiation with ultraviolet light, the compound undergoes a structural change known as photoisomerization, resulting in degradation of the MOF structure and simultaneous release of encapsulated cargo. To improve the clinical relevance of our framework, we focus on developing synthetic methods for production of visible light-responsive azobenzene photoswitches. A green light-responsive MOF (UiO-AZB-F) containing a 4,4ʹ-(diazene-1,2- diyl)bis(3,5-difluorobenzoic acid) linker was developed as a drug delivery system for the treatment of colorectal cancer. Our work also focuses on optimizing various aspects of MOF design to maximize and diversify cargo loading and precisely control cargo release rates. A combined computational and experimental investigation of drug adsorption process reveals that the presence of solvent can significantly impact the adsorption of drug molecules within MOF pores. To address these concerns, a variety of drug loading procedures were screened to determine conditions for maximizing the loading of diverse drug cargoes. Conditions for the loading of single agents as well as chemotherapy cocktails were explored to expand the application of our delivery platform to other cancer types including lung, pancreatic, bladder and cervical. To modulate the release of cargo, a series of MOFs containing precise ratios of green light-responsive linker were synthesized to create a platform for sustained release. Remarkably, several MOF derivatives showed enhancement in drug adsorption, highlighting the important role of host–guest interactions in nanocarrier development. Holistically, this work highlights the promise of stimuli-responsive MOFs as drug delivery platforms.

Depositing metal-organic frameworks (MOFs) on the surfaces of metal nanoparticles (NPs) to enhance catalytic selectivity has recently attracted great attention; however, a solid understanding of how the NP-MOF interface promotes catalytic selectivity is lacking. In this thesis, we have conducted three fundamental studies and further applied the knowledge to other types of catalysts using enzymes. The first part of this thesis focuses on understanding the NP-MOF interfacial structures and their impact on catalytic performance. We have systematically probed the NP-MOF interface generated by three commonly used approaches by IR and Raman spectroscopy. We have revealed significant differences in interfacial chemical interactions between them, and have found that these differences in interfacial structure dramatically impact selectivity. For example, the interface generated by the coating approach contains trapped capping agents. This trapped capping agent reduces crotyl alcohol selectivity for the hydrogenation of crotonaldehyde. The second part of this thesis focuses on addressing the trapped capping agents at the NP-MOF interface. We developed an approach to creating a direct NP-MOF interface by utilizing weakly adsorbed capping agents during the MOF coating process. Their dynamic nature allows for their gradual dissociation from the NP surface with the assistance of the organic MOF linkers. Thus, direct chemical interactions can be built between NP and MOF, generating a clean and well-defined interface. Direct evidence on capping agent dissociation and formation of chemical interactions was obtained by Raman and IR spectroscopy. Combined with transmission electron microscopy and X-ray diffraction, we have revealed the relative orientation and facet alignment at the NP-MOF interface. The third part of this thesis investigates how various MOF components affect the selectivity of hydrogenation reactions catalyzed at the MOF-NP interface. We found that the replacement of Zr-oxo nodes with Ce-oxo nodes yields the highest selectivity for cinnamyl alcohol (~87%), whereas the functionalization of the terephthalic acid linker with -OH, CH3, -NO2 and NH2 groups only moderately modulates the selectivity relative to the Zr-UiO-66 (~58%). Reaction kinetics studies demonstrate that coating Pt NPs with Ce-UiO-66 increases the rate of C=O hydrogenation, which infrared spectroscopic observations suggest is due to the interaction of the C=O group with the Ce-oxo node. This work highlights the critical role of metal-oxo nodes in regulating the catalytic selectivity of metal NPs in specific reactions. The fourth part of this thesis extends the interface control to other catalysts involving enzymes. We compared the interfacial interactions of catalase in solid and hollow MOF microcrystals. The solid sample with confined catalase was prepared through a reported method. The hollow sample was generated by hollowing the MOFs crystal, sealing freestanding enzymes in the central cavities of the hollow MOF. By monitoring this hollowing process, we observed that the enzymes gradually changed from a confined form to a freestanding form. The freestanding enzymes in the hollow MOFs show higher activity in the decomposition of hydrogen peroxide, attributed to their lesser chemical interactions and confinement. This study highlights the importance of the freestanding state for the biological function of encapsulated enzymes. Taken together, the four sections in this thesis establish design rules for refining MOF-based catalyst design.

A series of magnesium-based metal-organic frameworks (Mg-MOFs) were prepared and decorated with metal nanoparticles to develop hybrid sorbent/catalysts for carbon dioxide (CO2) capture and conversion to chemical fuels. A straightforward thermal treatment approach was first established to construct hybrid sorbent/catalysts. By exploiting the disparity in Ni-O and Mg-O coordination bond strength within mixed-metal NiMg-MOF-74, Ni2+ was selectively reduced to generate dispersed Ni nanoclusters constrained by the initial MOF pore diameter. By modifying the Ni:Mg ratio in the parent MOF, accessible surface area and framework crystallinity were tuned upon thermal treatment, influencing CO2 uptake and hydrogenation selectivity. The dispersed Ni nanoclusters proved to be an active catalyst towards CO2 hydrogenation, while the preserved section of Mg-MOF retained a portion of its CO2 adsorption capacity. To gain further insight into factors governing CO2 uptake and hydrogenation, the catalyst loading method was expanded to Mg-CUK-1. The optimised NiMg-CUK-1 was deployed within a dual-mode reactor system constructed for temperature swing CO2 capture and conversion to methane (CH4). Upon repeated cycles, the CH4 generated surpassed similar sorbent-based catalysts reliant on the chemical looping of metal oxides and carbonates. The approach highlighted the significant role of physisorption-based materials in facilitating low-temperature CO2 desorption, extending the working capacity of hybrid sorbent/catalysts. The dual-mode reactor system was extended towards industrially relevant CO2 capture conditions. Low catalyst loadings of Ru and Ni within stable Mg-CUK-1 enhanced overall system performance by preserving additional CO2 uptake. Simulated dry flue gas was deployed to probe the influence of oxygen exposure on catalyst performance. Ru-loaded Mg-CUK-1 sustained CH4 generation over ten cycles, while Ni-loaded Mg-CUK-1 registered a decrease in performance attributed to Ni passivation. When a portion of Ni was replaced with Ru, the resulting dual-metal catalyst emulated the performance of the monometallic Ru hybrid sorbent/catalyst. Ru was found to aid the re-reduction of surface Ni2+ to Ni0 upon oxygen exposure, which resulted in sustained CH4 generation. The strategy developed provided an approach to foster resilient hydrogenation catalysts capable of withstanding reactive species when exposed to point source CO2 emissions.

Metal organic frameworks (MOFs) are a novel class of solid materials, comprising inorganic metal nodes and multidentate organic ligands. These materials have drawn wide attention as potential catalysts. Microscopic characterization of these structures has become routine with x-ray diffraction (XRD) crystallography and determination of surface area/pore volume data by analysis of adsorption isotherms, analyzed with Brunauer-Emmett-Teller (BET) theory. However, competition for the nodes in synthesis between the organic linkers, acid modulators, and the solvent matrix results in structural defects that are not resolved by these microscopic techniques. These defects are capped with inhibiting ligands that block access to catalytically active sites. Alcohol dehydration reactions offer opportunities to investigate these active sites as reactant alcohol will remove the inhibiting capping species, and (more slowly) the organic linker. Revealed vacancies will expose different active sites capable of catalyzing alcohol dehydration reactions. MOF UiO-66, which incorporates Zr6O8 nodes and 1,4-benzene dicarboxylate linkers and is known for its stability, was investigated with methanol and isopropanol dehydration as test reactions. Catalyst performance was determined with a once-through flow reactor at atmospheric pressure and temperatures of 473–573 K. The products were analyzed by on-line gas chromatography, and catalyst samples removed from the reactor after various times on stream were characterized by X-ray diffraction crystallography, surface area measurements, scanning electron microscopy, and 1H NMR spectroscopy of samples digested in NaOH characterizing the collapse of the MOF structure and deactivation of the catalyst. The deactivation was caused by alcohol reacting to form node alkoxy ligand and to break node–linker bonds, unzipping the MOF and creating amorphous material preferentially near the MOF particle surfaces. The methods implemented in this work are suggested to be of value for assessing the strengths and limitations of MOFs as practical catalysts.

Post-combustion capture is one of the leading technologies for CO2 abatement from anthropogenic sources which have contributed significantly to the rise of atmospheric greenhouse gases. Specifically, solvent-based capture post-combustion processes are the industry standard but can suffer drawbacks such as high energy penalties and corrosion. In this work, two possible improvements are investigated which have been recently proposed in the literature. The first is aqueous ammonia as a capture solvent which has been shown to have several advantages including, but not limited to, a lower regeneration energy. The second is a novel solid sorbent, an amine-appended metal-organic framework (MOF). The MOF exhibits several promising attributes, namely, a step-shaped adsorption isotherm which leads to lower working capacities and lower regeneration energies when compared to traditional solid sorbents. The overall goal of this work is to develop rigorous mathematical models which can be used for process design and economic evaluation of these technologies. First, an integrated mass transfer model is developed for the chilled ammonia process (CAP). This model is developed using a simultaneous regression approach that has been recently proposed in the literature with parameter estimation performed using data from a pilot plant source and wetted-wall column. The optimally estimated parameters are shown to have a lower prediction error to validation data than parameters found in literature. The integrated mass transfer model is then used to develop a model for a novel chilled ammonia process. The process includes a NH3 abatement system which utilizes a reverse osmosis membrane to aid in separation and reduce the energy penalty. Simulation of the process shows that the membrane can significantly reduce the energy requirement of the reboiler, condenser, and cooler in the abatement section. Uncertainty of the estimated mass transfer parameters is quantified using a fully Bayesian approach which is demonstrated to show a significant reduction in the prediction uncertainty of key process indicators. Second, isotherm and kinetic models are developed for amine-appended MOFs, dmpn-Mg2(dobpdc) and Mg2(dobpdc)(3-4-3). The step-shaped adsorption isotherms exhibited by these MOFs present a modeling challenge since many of the traditional isotherm models are unable to capture step transitions. Three isotherm models are examined in this work, a weighted dual-site Langmuir model found in literature, a dual-site Sips model developed in this work, and an extended weighted Langmuir model also developed in this work. Parameter estimation is performed using available isotherm data and it is shown that the models are able to predict the CO2 adsorption data well. A kinetic model is then developed using a linear driving force for mass transfer which does an excellent job at predicting time dependent TGA data. An additional goal of this work is development of a chemistry-based model for functionalized solid sorbents that aims to capture the underlying adsorption reaction mechanisms which are not typically considered in solid sorbent modeling. As part of this model, optimal reaction set selection is performed since the reaction pathways for dmpn-Mg2(dobpdc) are still relatively unknown. Parameter estimation is performed, and it is found that the chemistry-based model significantly outperforms the Sips isotherm model with regards to prediction error and other model building criteria. To aid in the evaluation of the commercial feasibility of the MOF, equation-oriented mathematical models for a fixed bed contactor and moving bed contactor are developed. The contactors are then to simulate industrial scale CO2 capture process for coal based and NGCC based flue gas. Using developed cost models, techno-economic analysis and optimization of these processes is then performed and it is found that efficient thermal management can make these MOFs viable alternatives for CO2 capture processes.

The dissertation is dedicated to the design and synthesis of magnetic and conductive metal–organic frameworks using insights learned from molecular coordination chemistry with a bottom-up approach. Further, the dissertation demonstrates that metal and ligand substitution is a viable strategy to tune electronic structures and physical properties.

Metal-organic frameworks (MOFs), as a type of inorganic-organic hybrid porous materials, have attracted enormous research interests over the past two decades due to their extraordinary variability and richness of their chemistry and structures. The original design on MOFs is in pursuit of and high surface area, typically for gas storage. However, the properties in a simple MOF system could not meet the needs for a wide variety of advanced applications. Therefore, it is highly desirable to introduce multiplicities and impart functionalities into MOFs through materials design. In this regard, this dissertation focuses on engineering MOFs in two strategies, constructing heterostructures, fabricating thin films, and evaluating their impact on catalysis and energy conversions. The first chapter focuses on constructing a well-defined interface between materials with vast differences in structural dimensions. Another highlight of this study lies in developing characterization protocols to characterize interfacial structures. In the second part, a MOF-74 thin film with crack-free nature serves as a promising platform for the study of ion transport. The last part of this dissertation reports a new two-dimensional (2D) structure derived from UiO-66. The 2D structure was attained by limiting the coordination number and inducing anisotropic growth. The layered material could be further exfoliated and fabricated into thin films. This work presents strategies to impart functionality to MOFs with rational material design and elucidate their positive impacts on the performance of the whole system.

Metal-organic frameworks are hybrid materials constructed by inorganic metal nodes and organic linkers. The presence of both organic and inorganic moieties in the structure allows MOFs to have a significant flexibility and tunability in compositions, structures, and functional properties. This in turns enables MOFs to have very desirable and interesting properties, such as very high porosity, very high surface area, multiferroicity, electrical conductivity, proton conductivity and others. Consequently, MOFs have potentials in a wide array of applications, including catalysis, gas storage and separation, energy storage and drug delivery.Despite the significant amount of research performed on the development and synthesis of MOFs, fundamental study of their intrinsic stability is still fragmentary. The thermodynamic properties of materials are crucial in understanding their properties and evaluating their intrinsic stability. To accelerate the discovery of new MOFs, it is necessary to study the energetics of MOFs systematically to further understand how the compositions and structures affect stability. By relating these composition – structure – energetics relationships to other measurable, calculable, or available chemical properties, it should be possible to predict the stability of new MOFs. Therefore, this dissertation work aims to fulfill this goal of understanding and predicting MOF stability. Chapter 1 is a general introduction. Chapter 2 discusses the synthesis, characterization and thermodynamic study of mineral paceite CaCu(OAc)4‧6H2O as well as its cadmium-based analogue CaCd(OAc)4‧6H2O. The enthalpy of formation revealed the destabilization introduced by the Cd to the structure. Additionally, it also explained the most possible synthesis route of paceite, which is through the formation of a calcium acetate – acetic acid solvate intermediate. Chapter 3 presents a systematic study of the energetics of A-site cation substitution on the thermodynamic stability of protonated-amine manganese formate perovskite. This system was chosen representative of a dense MOF system. The measured enthalpy of formation revealed that the stability of hybrid perovskites is not strongly influenced by the structural factor, unlike its inorganic perovskite counterparts. Instead, the stability is governed more by the interaction of the A-site cation with the framework, which further can be explained by the dissolution enthalpy of the cation salts. Chapter 4 reports the interplay between theoretical calculations and experimental measurements to determine the thermodynamic stability of porous metal organic frameworks, in this case fluorinated zeolitic imidazolate frameworks (ZIFs). The enthalpy of formations revealed the strong influence of ligand functionalization and topology on the stability. Chapter 5 presents a systematic study of the energetics of ligand substitution on the stability of ZIFs with sodalite structure. Based on the results obtained in Chapter 4, this study was designed to see only the contribution of ligand substitution to stability, while keeping the topology the same. It was found that the stability trend of sodalite ZIF samples with different ligand functionalization can be explained by a tabulated chemical property from physical organic chemistry, namely Hammett -para(+) constant. Lastly, in Chapter 6, all the results are related with summarizing points and suggestions for future research will be presented.

This dissertation explores the functionalization of woven cotton fabrics by solvothermal synthesis with two different metal-organic framework (MOF) systems, a zeolite-like (ZIF-8) MOF and Zirconium-based MOF (UiO-66, isostructural UiO-66- NH2, and isoreticular UiO-66-NDC and UiO-67). The use of these functionalized fabrics as adsorbents for micropollutants and as potential photocatalysts is also presented. The micropollutants selected cover inorganic as well as organic substances. In the first part of this thesis, the synthesis pathways for ZIF-8 decorated cotton involve seeding and growth of zinc oxide (ZnO) onto the fabric and the subsequent modification of ZnO to ZIF-8 using a one-step synthesis method. The result of our approach was a core-shell structure, ZnO as a core and ZIF-8 as a sheath, conformally deposited on the surface of the cotton fiber. Nitrogen adsorption onto ZIF-8 fabrics allowed to calculate a ZIF-8 content of 5% w/w. Arsenate (As (V)) uptake at pH 7 was investigated and the ZIF-8 fabrics demonstrated a higher uptake (70%) than the ZnO fabrics (38% uptake). Additionally, Zinc loss from the fabric into solution was lowered in the case of ZIF-8 decorated cotton. The growth of UiO-66 onto the cotton fabric is presented in the third chapter. UiO-66 crystals grew in a uniform and conformal manner over the surface of the cotton fibers forming a layer of approximately 50 _m around the cellulose fibers. The cotton fabrics functionalized with UiO-66 frameworks exhibited an enhanced uptake capacity for methylchlorophenoxypropionic acid (MCPP), a commonly used herbicide. The functionalized fabrics also showed photocatalytic activity, demonstrated by the degradation of acetaminophen, a common pharmaceutical compound, under simulated sunlight irradiation. In the fourth chapter, cellulose functionalization was expanded to the isostructural MOF UiO-66-NH2 as well as to isoreticular MOFs UiO-67 and UiO-66- NDC using adapted solvothermal synthesis conditions. A thorough characterization of the MOFs is first presented, and a deeper dive into fundamental understanding of the functionalization is presented. Finally, the conclusion summarizes the findings, explores the next steps with supported proof of concept presented in Appendix 1 through 3, and concludes the research presented in this thesis.

The diverse chemical properties of compounds containing metal atoms are inherently highly tunable. In terms of size, they may be small molecular complexes consisting of only 1 or 2 metal atoms or, at the other extreme of scale, they may be crystalline solids with clusters of metal ions periodically dispersed in the structure of a metal–organic framework (MOF). In both cases, relevant chemistries can be tailored to fit specific needs, especially with respect to catalytic reactivity. For a molecular catalyst, the combination of metal atom and its ancillary ligand can be chosen carefully to optimize selectivity and activity, while in three-dimensional MOFs, the metal clusters (called nodes) and connecting organic molecules (called linkers) can be ‘mixed and matched’ to best suit a particular application. Because of the inherent complexity of these systems, experimental characterization of structure/activity relations can often be challenging. Starting from a set of reactants, obtaining a mechanistic picture of the steps leading to the product formation is also demanding since isolation of an intermediate does not necessarily guarantee involvement of the species in the ‘productive’ pathway of the mechanism. Theory and computation can be immensely helpful in these instances to gain molecular-level understanding of the reaction mechanism(s). One can explore multiple pathways that yield the product and then evaluate the feasibility of each pathway by comparing computed energetics. Mechanistic knowledge can then be exploited to establish a structure/property relation, thereby fostering the design of subsequent generations of the catalytic species, ideally having improved performance, and helping to further refine the overall model. This dissertation demonstrates the use of computational methodologies, primarily quantum mechanical density functional theory, to explore the electronic structures of various metal-organic systems and the roles they play in carrying out targeted catalytic processes. In particular, computational modeling efforts are presented that illuminate (i) mechanisms of sustainable polymer production and principles for designing new catalysts (Chapter 2), (ii) site-selective C–H bond functionalization having relevance in drug discovery and chemical biology (Chapter 3) (iii) C–H activation reactions in light hydrocarbons using bio-mimetic copper-complexes having the potential to address challenges in fuel liquefaction (Chapter 4), and (iv) MOF-based single-site heterogeneous catalysts capable of oxidation reactions having industrial relevance (Chapter 5).

Metal-Organic Frameworks (MOFs) are an exciting new class of porous materials that display exceptional structural diversity and broad functional tunability. These materials are of particular interest for gas storage, separations, and catalysis. This work centers on the creation of new MOF materials incorporating P(III) and As(III) Lewis basic sites, known as Phosphine/Arsine Coordination Materials (PCMs/ACMs). These permit the incorporation of secondary 4d/5d metals bound to the soft P(III)/As(III) lone pairs before, during, or after MOF formation. In this sense, PCMs/ACMs can act as solid-state ligands, binding reactive metals in well-defined coordination environments while orienting them periodically throughout a porous crystalline structure. The presence of these secondary metals can drastically enhance the performance of the materials for targeted applications. The first reported triarylarsine-containing MOF, ACM-1, was obtained using a unique arsine linker with phenylpyridyl linkages. ACM-1 was metallated with Au(I) post-synthetically to yield Au-ACM-1, which was characterized by single-crystal X-ray diffraction. The material incorporated Au₂Cl₂ dimers in a sterically constrained cis-As2 pocket, which resulted in an exceptionally short Au···Au aurophilic contact of 2.76 Å. Incorporation of Au(I) allowed the material to function as a heterogeneous catalyst for the hydroalkoxylation of 4-pentyn-1-ol, and also enhanced the solid-state luminescent properties of the material. A broad library of triaryl arsine ligands and new ACMs was achieved, most of which were structurally characterized and evaluated as solid-state ligands. Other materials were obtained with trans-oriented Lewis basic sites. PCM-102 was structurally characterized and found to be a versatile solid-state ligand. Upon addition of low-valent metals, the framework undergoes a distortion to form trans-P₂M complexes (M = Cu(I), Ag(I), Au(I), Rh(I)). Metallation of PCM-102 was found to drastically enhance the gas uptake properties of the resulting materials, and the Ag(I) material was evaluated for the separation of propane and propylene. Additionally, one of the first examples of Lewis acid pillaring was achieved in Ag-PCM-201, in which Ag(I) connects adjacent two-dimensional sheets to form a three-dimensional structure. This was also accomplished using an Os(I) dimer in Os₂-PCM-201, which displayed interesting reactivity and selectivity for adsorption of H₂.

1,6,7,12-tetrachloroperylene tetracarboxylic acid anhydride (PDACl4) is a fluorescent dye with a wide range of tunability. This work explores the functionalization of PDACl4 to exploit its supramolecular and photovoltaic (PV) capabilities. Synthesis of a novel pillared paddlewheel (PPW) metal-organic framework (MOF) using a bipyridyl functionalized tetrachloro perylene diimide (BPyPDICl4) pillar with 2,6-naphthalenedicarboxylic acid (2,6-NDC) struts was successfully achieved and confirmed with X-ray diffraction (XRD). The growth of the new MOF as a thin film on both zinc oxide and titanium dioxide-coated fluorine-doped tin oxide (FTO) glass was explored for its potential use in dye-sensitized solar cell (DSSC) type application using powder x-ray diffraction (PXRD), UV-Vis, and diffuse reflectance (DR) spectroscopy. Other solvothermal syntheses of UiO, MOF-5, and PPF-type MOFs using tetrachloro perylene diimide (PDICl4) ligands were performed and discussed. Organic synthesis of a new 4-tert-butylaniline based tetrachloro perylene diimide is reported along with its potential as a reaction intermediate. Bay substitution with cyclohexylamine, pyrrolidine, 1,2-dimethylhydrazie, 2-methoxyethanol, and pentaethylene glycol on various PDICl4 derivatives is investigated through different synthetic routes with a final goal of substituting all four bay position with electron-rich or cation-coordinating moieties on a perylene diimide with metal-coordinating imide groups. Future direction for the novel MOF and the application of the newly synthesized PDI ligands in MOF application is discussed.

Access to clean water is one of the world's foremost challenges that has been addressed on a large scale by membrane-based separation processes for the last six decades. Commercial membrane technology within one operation, reverse osmosis, has remained consistent since the late 1970s, however within the last two decades, access to nanotechnology has created a realm of study involving thin film nanocomposite (TFN) membranes, in which nanoparticles are incorporated into existing membrane designs. Desirable properties of the nanoparticles may positively impact qualities of the membrane like performance, anti-fouling behavior, and physical strength. In the present work, two types of nanoparticles have been evaluated for their potential as TFN additives: cellulose nanocrystals (CNCs) and metal-organic framework (MOF) nanorods. CNCs were chosen due to their high aspect ratios, mechanical strength, and potential for surface functionalization. MOF nanorods are also of interest given their aspect ratios and potential for functionalization, but they also possess defined pores, the sizes of which may be tuned with post-synthetic modification. Both CNCs and MOF nanorods were incorporated into TFN membranes via interfacial polymerization, and the resulting membranes were characterized using a variety of techniques to establish their performances, but also to gain insight into how the presence of each nanoparticle might be affecting the membrane active layer formation. A resulting CNC membrane (0.5 wt% loading) exhibited a 160% increase in water flux and an improvement in salt rejection to 98.98 ± 0.41 % compared to 97.53 ± 0.31 % for a plain polyamide control membrane. Likewise, a MOF nanorod membrane (0.01 wt% loading) with a high ratio of acid chain modification exhibited a 95% flux increase with maintained high salt rejection. For the CNCs, the flux increase is attributed to the formation of nanoscale voids along the length of each particle that form during the interfacial polymerization. These nanochannels introduce new rapid water transport pathways within the active layer of each membrane while maintaining ion rejection. The proposed mechanism for the MOF nanorods also introduces nanochannels into each membrane, but the presence of each nanorod's pore structure may offer another transport pathway for water molecules, one that varies with pore size. In combination, these results have allowed the study of molecular transport of water molecules and various ion species within the active layer of a thin film composite RO membrane. Understanding these phenomena will allow the development of smarter membrane materials to address present-day and future separations challenges. Carbon nanotubes are also demonstrated as surface modifiers for forward osmosis (FO) membranes to address issues unique to the FO process, namely reverse solute flux (RSF). This method shows promise, as a coating density of 0.97 g/m2 reduced RSF for many draw solution species, including a 55% reduction for sodium chloride.

High-performance functional electrode materials are critical for the development of electrochemical energy conversion and storage technologies. Among various advanced materials, three-dimensional (3D) porous structures have attracted extensive interest due to their high surface area and capability for efficient mass transport. Metal-organic frameworks (MOFs) are a novel class of porous coordination polymers constructed with organic linkers connected by inorganic nodes. Their extraordinarily high surface area, permanent pores/channels, good thermal and chemical stabilities have made MOFs one of the most promising materials for various electrochemical applications, including electrocatalysis, supercapacitors, Lithium-ion batteries, chemical sensors, etc. The present dissertation focuses on the investigation of charge transfer mechanism in MOF films so as to establish design rules for future MOF design, and the exploration of MOF-based materials for electrochemical and photoelectrochemical applications. To promote the use of MOF-based materials in electrochemical applications, efficient charge transfer is a necessity. In redox-active MOFs, charge transfer can happen through redox hopping, i.e. site-to-site electron hopping coupled to diffusion of counter ions to balance electroneutrality. While the apparent diffusion coefficient (Dapp) has been employed to describe the overall charge transfer efficiency, independent elucidation of electron and ion diffusion is crucial for providing insights into the mechanism of charge transfer in MOFs. In Chapter 2, we investigated the MOF pore size effect on electron and ion diffusion. Three redox-active ferrocene-doped MOF (Fc-MOF) films with different pore sizes immobilized on conductive substrates were prepared, and electron and ion diffusion coefficients and rate constants were quantified by applying a theoretical model to chronoamperometric responses. Increasing MOF pore size led to an increase in ion diffusion rate constant and a decrease in electron diffusion rate constant. The overall charge transfer rate constant increased when MOF pore size increased, implying the ability of promoting efficient charge transfer through control of MOF pore size. As charge transfer via redox hopping proved to be feasible, Chapter 3 focused on the application of a ruthenium(II)-polypyridyl doped MOF film immobilized on a conductive substrate, UiO-67-Ru@FTO, for solid-state electrochemiluminescence (ECL). In the presence of tripropylamine as a coreactant, UiO-67-Ru@FTO exhibited higher ECL intensity and better reproducibility compared to corresponding solution-based ECL system. Subsequently, UiO-67-Ru@FTO was successfully used for dopamine detection, highlighting the great potential of using MOF-based materials as solid-state ECL detector for practical applications. Covalent-organic frameworks (COFs) are a recently emerging family of crystalline organic polymers constructed with organic building blocks linked by covalent bonds. In addition to advantages including high surface area and high porosity that are similar to MOFs, COFs possess low density due to the constitution of light-weighted elements and excellent stability owing to the robust covalent bonds. Therefore, it is of our interest to investigate the properties and potential applications of COFs. Two-dimensional (2D) COFs are composed of conjugated organic layers stacked via - interactions. Chapter 4 focused on understanding the effects of intraplanar -conjugation and interplanar -stacking on the photophysical properties of a 2D COF, TpBpy. Compared to the two building blocks, TpBpy exhibited a red-shifted emission, due to the - stacking. Density functional theory (DFT) calculations were performed on energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). It was found that the extended structure of the framework resulted in a decrease in the HOMO-LUMO gap. The experimental and computational studies reveal the important influence of intraplanar and interplanar interactions on photophysical properties in 2D COFs. In Chapter 5, we modified the COF TpBpy with nickel(II) and investigated its application as an electrocatalyst for 5-hydroxymethylfufural (HMF) oxidation. Unlike TpBpy characterized in Chapter 4, TpBpy thin films were prepared by an interfacial crystallization strategy. The films were transferred to conductive substrates and then post-synthetically modified by nickel acetate. Similar to redox-active MOFs, the resulting TpBpy-Ni COF film exhibited redox conductivity. TpBpy-Ni showed good catalytic activity for HMF oxidation under basic conditions. This study suggests the great potential of functionalized COFs for electrochemical applications.

Biological systems have evolved over time to favor structures beneficial for the efficient transformation of simple feedstocks to sophisticated products. In particular, enzymes have evolved such that cooperative and geometrically controlled interactions between active sites and substrates enhance catalytic activity and selectivity. Separation of these active sites from other incompatible catalytic components allows for chemical transformation in a stepwise fashion, circumventing the inherent limitations to performing reactions in a single step. This dissertation describes the use of porous crystalline materials called metal-organic frameworks (MOFs) as hosts to mimic the component separation and precise active site control observed in nature. The first phase of these efforts explores the use of dissociative “aperture-opening” linker exchange pathways in a MOF to encapsulate transition metal complexes for carbon dioxide hydrogenation to formate. This strategy is then used to separate two incompatible complexes and perform the cascade conversion of carbon dioxide to methanol, resulting in unique and previously unobserved network autocatalytic behavior. Finally, the modularity of the MOF host is leveraged to install beneficial functionality in close proximity to the encapsulated transition metal complex, leading to activity exceeding that of any reported homogeneous system for carbon dioxide reduction. The insights gained through these studies can inform the development of composites for other reactions, allowing for access to new and unique reaction manifolds.

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.

The advancements of chemists, engineers, and material scientists has yielded an enormous and diverse library of high-performance materials with varying chemical and physical properties that can be used in a wide array of applications. A molecular-level understanding of the nature of gas–surface interactions is critical to the development of next generation materials for applications such as gas storage and separation, chemical sensing, catalysis, energy conversion, and protective coatings. Quartz crystal microbalance (QCM) and in situ infrared (IR) spectroscopic techniques were employed to probe how topological features of a material as well as structural differences of the analytes affect gas sorption. Detailed studies of the interactions of three categories of molecules: aromatic hydrocarbons, triatomic ambient gases, and chemical warfare agents, with metal-organic frameworks (MOFs) and polyurethane coatings were conducted to build structure–property relationships for the nature and energetics of gas sorption within each material. Differences in the molecular structure of the guest compounds were found to greatly influence how, and to what extent each molecule interacts with the MOF or polyurethane film. Specifically, IR studies revealed that transport of aromatic compounds within the zirconium-based MOF, UiO-66 was limited by steric restrictions as molecules passed through small triangular apertures within the pore environment of the MOF. In contrast, the smaller triatomic molecules, CO2, SO2, and NO2, were able to pass freely through the MOF apertures and instead reversibly adsorbed inside the MOF cavities. Specifically, SO2 and NO2 were observed to preferentially bind to undercoordinated zirconium sites located on the MOF nodes. In addition, uptake of CO2, SO2, and NO2 was also aided by dispersion forces within the confined pore environments and by hydrogen bond formation with μ3 OH groups of the MOFs. Dimethyl chlorophosphate (DMCP), a nerve agent simulant that contains several electronegative moieties, was also found to strongly adsorb to undercoordinated zirconium; however, unlike in the aromatic and triatomic molecule systems, DMCP remained permanently bound to the MOFs, even at high temperatures. Finally, QCM studies of mustard gas simulant uptake into polyurethane films of varying hard:soft segment compositions revealed that dipole-dipole and dipole-induced dipole interactions were responsible for favorable absorption conditions. Furthermore, the ratio of hard and soft segment components of the polyurethane had a minor impact on simulant adsorption. Higher hard-segment content resulted in a more crystalline film that reduced simulant uptake, whereas the rubbery, high soft segment polyurethane allowed for greater vapor absorption. Ultimately, molecular-level insight into how the chemical identity of a guest molecule impacts the mechanism and energetics of vapor sorption into both MOFs and polymeric films can be extended to other relevant systems and may help identify how specific characteristics of each material, such as size, shape, and chemical functionality impact their potential use in targeted applications.

Increasing energy demand will not only aggravate global warming, but also cause fossil fuels shortage in the near future. Solar energy is an infinite green energy resource that can potentially satisfy our energy usage. By utilizing solar energy to drive reactions like water splitting, solar fuels system are able to produce valuable energy resource. Catalysts for water oxidation are the essential component of water splitting cells which have been intensively studied. As a solid state porous crystalline material with synthetic tunability, Metal-organic framework (MOF) is a promising platform for water oxidation catalysis due to its outstanding properties. Herein, we aimed to develop molecular catalysts incorporated MOF for water oxidation and study the reaction mechanism. Chapter 1 introduces the background of water oxidation and previous research on ruthenium nuclear water oxidation catalysts (WOCs). The reaction mechanism of binuclear and mononuclear ruthenium WOCs was briefly summarized. Opportunities for the design and the synthesis of MOF based WOCs were then discussed. Lastly, studies about MOF based WOCs were categorized based on the difference of the WOCs active site location in frameworks. Water oxidation catalyst [Ru(dcbpy)(tpy)OH2]2+ (RuTB) was incorporated into UiO-67 MOF (resulting materials denoted as RuTB-UiO-67) for chemical water oxidation in Chapter 2. Differences of catalytic reaction behavior between homogeneous RuTB and RuTB incorporated in MOF were examined. Based on MOF particle size dependent catalysis reaction experiments, in-MOF reactivity was anticipated to be primarily arose from redox hopping between RuTB active sites in the framework. In Chapter 3, RuTB-UiO-67 MOF thin films grown on conducting FTO substrate (RuTB-UiO-67/FTO) were synthesized to test their catalytic activity of electrochemical water oxidation. Electrochemical behavior of RuTB-UiO-67/FTO was found to be consistent with homogeneous RuTB by various electrochemistry study and in-situ X-ray absorption spectroscopy characterization. Scan-rate-dependent voltammetry study demonstrated the homogeneous distribution of electrochemical active sites throughout the MOF thin film. Diffusion controlled redox hopping was attributed to be the main charge transfer pathway during catalysis. In order to pursue photo-induced water splitting system, we further our study by investigating MOF based photoelectrochemical catalysis in Chapter 4. Photoelectrochemical alcohol oxidation was chosen as the preliminary-stage study towards the more challenging goal, photoelectrochemical water oxidation. Electron transfer processes of the photosensitizer ([Ru(bpy)2(dcbpy)]2+) and the catalyst (RuTB) doped UiO-67 MOF were investigated with transient absorption spectroscopy analysis. Finally, the role of redox hopping in electrocatalysis by MOF was reviewed in Chapter 5. Pathways of charge transfer in electroactive MOF were first summarized. Redox hopping in MOF was then compared with previous studies on redox active polymer thin films. Lastly, factors that will affect the rate of redox hopping of MOF electrocatalyst were discussed.

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.

In this thesis, I have used computational methods to the study of flexibility in metal-organic frameworks (MOFs) and the behavior of adsorbed gases and liquids in MOFs. Among nanoporous materials, MOFs are of particular interest for adsorption-based applications for reasons that include (1) their huge chemical space, which raises the possibility of tuning them for specific industrial processes and (2) the ability of the under-coordinated metals present in some MOFs to endow their respective materials with impressive adsorbate binding energies.Chapters 2 and 4 relate to analogs of a series of MOFs with under-coordinated metals (the M-MOF-74 series). In Chapter 2, I report the discovery of a novel argon adsorbate-induced deformation pattern for this framework series. This result was arrived at using a flexible framework model, and is presented as an explanation for an intriguing signal observed in experimental small-angle X-ray scattering profiles upon argon adsorption. This hypothesis is supported by a complementary investigation of an alternative explanation for the X-ray signal, in which argon atoms are proposed to adsorb at different densities in adjacent pores.In Chapter 3, I studied the dynamics of adsorbed xylene isomers in MOF-5. I compare the translational and rotational motion of the xylene isomers, and explain the differences based on molecular geometries. The most rod-like molecule, para-xylene, is more rotationally constricted in the pore due to its intermolecular interactions with the aromatic group of the MOF linker. This finding has implications for the rational design of MOFs, as a process that can take advantage of the MOF-induced variations in xylene isomer dynamics could be used for lucrative liquid-phase xylene separations.In Chapter 4, I present a method for parameterizing the type of flexible framework model used in Chapter 2 from ab initio quantum chemistry calculations. The goal of this work is to facilitate the rapid development of flexible, versatile MOF models that can capture changes in the coordination bonding of metals in MOFs. This type of model can be used to study structural transitions and may be extended to study MOF formation. We demonstrated that our approach yields models for the M-MOF-74 series that are stable and have simulated structural properties in good agreement with quantum chemistry calculations.

Metal-organic frameworks (MOFs) are porous, crystalline solids formed from the self-assembly of metal clusters and organic linker molecules in solution. Covalent organic frameworks (COFs) are similar, formed from the combination of two or more organic molecules joined by covalent bonds to make an extended crystalline solid. Both of these materials have seen extensive research and development into both their synthesis and applications. The most common analytical techniques used to study these materials can sometimes fail to paint a full picture of these materials, whose structure and properties can change significantly under perturbations from adsorbates or different thermodynamic conditions. Additionally, these materials may contain disordered, aperiodic structures that may not be easily observed, but are central to their function. In this work, nuclear magnetic resonance (NMR) spectroscopy is used as an element-specific, non-invasive probe to study both the structures of MOFs and COFs, revealing defects, unique chemical sites, and heterogeneous distributions of functional groups, as well as the chemistry of molecules adsorbing and diffusing through these porous materials.The strong acid site in sulfated MOF-808 is identified using 1H solid state NMR in conjunction with other characterization techniques. The site is observed as a specific pairing of water and sulfate on the surface of zirconium clusters leading to a hydrogen bonding interaction which results in one of the protons on the water molecule becoming acidic. The structure arises as a specific sequence of molecules on an otherwise disordered surface of the MOF material, revealing powerful functionality arising from disorder.A 1H NMR pulsed-field gradient (PFG) probe is built and tested, and is shown to be capable of performing diffusion NMR studies of solvents and gases within MOFs. The probe is then used to study the diffusion of solvents in mixed-linker MOF-5. We find that the self-diffusion coefficient of N,N-dimethylformamide (DMF) may be tuned linearly between the diffusion coefficients of MOF-5 and IRMOF-3 as a function of the linker mole fraction. By comparing the diffusion coefficients for a series of solvents at saturation in MOF-5 and IRMOF-3, we conclude that average pore aperture, not solvent-linker chemical interactions, is the primary mechanism by which the linker amino groups tune molecular diffusion.NMR is applied to the understanding of 2D stacked COF materials. Although these materials are relatively crystalline, domain sizes of the crystallites are incredibly small, rendering structural determination by X-ray diffraction very difficult. Solid state NMR enables observation of chemical sites within these materials, and is applied to the monitoring of chemical conversion of covalent bonds by oxidation in imine COFs. Using isotopic labeling, the conversion is observed to be complete. Additionally, resonances attributable to defect sites are observed and quantified.CO2 capture in a primary amine-functionalized MOF is explored by using solid state NMR to study materials that have been exposed to 13CO2 at known partial pressures. An apparatus is built to dose activated MOF material in a solid state NMR rotor with 13CO2. It is found that CO2 is adsorbed as a carbamic acid under dry conditions, a relatively uncommon chemical species, and is adsorbed as the more commonly observed ammonium carbamate when adsorbed water is present. These results help to explain the material’s robustness in capturing CO2 selectively in the presence of water.

This dissertation documents efforts to use a variety of synthetic approaches to generate new redox-active metal–organic frameworks and improve the properties of known frameworks. Chapter 1 introduces the field of metal–organic frameworks and discusses observed redox activity of metal nodes and organic linkers. Additionally, the application of the Langmuir-Freundlich gas adsorption model and the use of IAST selectivity calculations to quantify and predict gas sorption in metal–organic frameworks are discussed. Chapter 2 discusses the successful targeted synthesis of the templated, mixed-metal framework Fe–Zn(dobdc) with proposed short-range order in the metal distribution. This ordered system demonstrates thermal stability for O2 adsorption compared to both monometallic Fe2(dobdc) and nontemplated Fe~Zn(dobdc) via a suite of in situ techniques. Chapter 3 documents the first isolation of the highly oxygen-sensitive framework FeII(H2gallate)∙2H2O. This unusual material exhibits remarkable permanence of crystallinity upon exposure to air as shown by single-crystal-to-single-crystal diffraction experiments. Isothermal gas adsorption measurements reveal an unparalleled selectivity for ethylene over ethane stemming from size exclusivity in narrow framework pores. The redox activity of this system is leveraged to tune gas sorption properties in a mixed-valent isomer: FeII/III(Hxgallate). Chapter 4 details efforts to apply several different solvent-free synthetic approaches to the synthesis of both iron- and early transition metal-containing frameworks. Melt based reactions are used to obtain a layered two-dimensional solid, Fe(bzimid)2, as well as the crystalline metallocene-derived materials Cr–bzimid and V–bzimid. A high-temperature metal-powder-based synthetic route is successfully applied for the first time for an iron-based metal–organic framework in the case of Fe(imid)2. Additionally, air- and solvent-free ball milling is shown to increase reaction yields for metal–gallate frameworks and provide evidence of redox activity in the gallate linker. Lastly, Appendix A details the design and use of the Breen adapter, a glass tube adapter with important uses in the field of metal–organic frameworks.

This dissertation documents efforts to control and take advantage of crystallization handles in metal–organic framework synthesis. Understanding fundamental processes during synthesis allows for directed, predictable control over crystallite size and shape, which is demonstrated to play a role in intracrystalline diffusion. Chapter 1 first introduces a summary of crystallization and transport in porous materials, including classical and non-classical models of crystallization, homogeneous and heterogeneous nucleation, and mass transfer resistances. The application of these concepts to metal–organic frameworks is presented alongside common synthetic strategies, coordination modulation and other strategies to control crystallite size and shape, and the potential for non-coordinating bases and buffers to help alleviate some complicating factors common to framework synthesis. Finally, because crystallite size and shape can control intracrystalline path lengths, an introduction to mass transfer resistances is given, including intracrystalline diffusion. Different methods of measuring diffusion in porous materials are presented, including the technique applied in this work, zero-length column chromatography (ZLC). Chapter 2 details success in deconvoluting solution equilibria during hydrothermal metal–organic framework synthesis. The use of non-coordinating bases and anions allows for generalizable increase in crystallite size. Further, non-coordinating buffers may be used during synthesis to add or subtract individual coordinating anions at a given pH. This strategy allows for tunable and predictable control over aspect ratio in a one-dimensional metal–organic framework. Chapter 3 describes the discovery and utilization of interfacial effects during hydrothermal synthesis to control crystalline phase and size. Controlling the interface between reaction vessel and solution via silanization is found to decrease morphological distribution, change the phase produced for stock solutions, and in some cases, increase crystallite volume by several orders of magnitude. Chapter 4 details the assembly and usage of a ZLC instrument capable of differentiating between different mass transfer resistances. Design considerations and instrument improvements are described. The instrument is used to probe CO2 diffusion within very large crystallites (up to 700 microns in length) of Zn2(dobdc), where surface resistances and defects are proposed to account for a lower diffusivity measured via ZLC versus pulsed-field gradient NMR. Synthetic control over Co2(dobdc) path length is demonstrated to bring about improved mass transfer resistances via path length control for the industrially important molecule m-xylene.

As the energy related activities turn out to be the “culprits” for CO2 emissions, the post combustion capture (PCC) technology has been regarded as a potential solution for carbon footprint mitigation. For this purpose, metal-organic frameworks (MOFs) have been regarded to provide opportunities as a more energy-efficient alternative to the conventional sorbent e.g. monoethanolamine owing to its high selectivity for CO2 and hydrothermal stability. In recent decades, efforts have been focused on two perspectives: cutting down the energy use per adsorption cycle and enhancing the working capacity. Thus, most of current researchers have defined their system boundary by only incorporating the adsorption and desorption phase. Within this study, a comprehensive life cycle model is developed to capture the overall environmental impacts of which does include the manufacturing, adsorption, desorption, and compression phase. To provide a systematic guide for material engineers, chemical engineers or even policy makers, different types of MOFs are considered and modelled in terms of various impact categories. In this study, we found that using MOF-74s as CO2 sorbents is more attractive than other MOFs that were analyzed such as ZIF-79, ZIF-81, PPN-6-DETA. To reduce the life cycle environmental impacts of MOFs, we investigated a series of factors at three levels: parameters, unit processes, and reaction stages. From each of them, we identified several contributors to the overall environmental impacts. In the case of unit process, several candidates of precursors were identified based on a hotspot analysis. Besides, use of dimethylformamide (DMF) was also found to contribute to the high life cycle impact, so seeking alternatives or improving efficiency of use are needed. Combining conventional LCA with machine learning (ML) yielded some preliminary heuristics for sustainable design of MOFs that have a smaller life cycle impact. One such heuristic is that MOFs with parasitic energy consumption larger than 947 MJ/t CO2 tend to have a larger life cycle environmental impact, making them less attractive.

Herein I report the thesis work on halide directed synthesis of indium derived metal-organic frameworks (MOFs). Building upon work done by a previous graduate student, conditions to produce phase-pure MOFs were investigated by varying temperature and concentration of salt-additives. A phase table was compiled and data trends were observed, showing MOF isomerism between In-derived MOFs YCM-31 and YCM 32, as well as ZJU-28 and an isomer of ZJU-28.

Metal-organic frameworks (MOFs) are a class of porous coordination polymers that has been the subject of intense investigation since there discovery almost 30 years ago. The combination of organic linker and metal node in a 3-dimensional framework leads to materials that are tunable, have high surface area and in most cases are highly porous. The applications of these materials spans from gas storage to catalysis. Chapter 2 describes the utilization of MOFs to catalyze the carbonation of propylene oxide to propylene carbonate. The design and construction of a packed-bed flow reactor was undertaken to allow systematic investigation. This systematic investigation of co-catalyst, catalyst synthesis, catalyst activation, node metal and node geometry resulted in high yielding conditions with low CO2 pressure (1-10 bar) and no added co-catalyst, conditions that previously, under batch conditions, lead to poor yields. These studies eventually resulted in the identification of a new catalyst, MIL-100(Sc), for this reaction. Chapter 3 investigates post-synthetic modification of MIL-101-SO3X through cation exchange. MIL-101-SO3X was treated with various potassium salts resulting in substitution at the sulfonate and establishing a relationship between conjugate acid pKa and MOF degradation. The exchange process demonstrated allow for rapid and complete conversion between protonated (–SO3H) and alkali metal exchanged (–SO3X) through brief (10 min) treatment with bicarbonate base followed by alkali chloride salt treatment for 1 h or by the utilization of high equivalents of alkali chloride salt relative to incorporated sulfonate. The exchange process was successful in generating previously unreported MIL-101-SO3X loaded with K, Rb, and Cs. Chapter 4 expands upon post-synthetic modification by investigating the conversion of aminated MOFs (IRMOF-3, UMCM-1- NH2, MIL-53(Al)-NH2, and UiO-66-NH2) into sulfonated MOFs by reaction with 1,3-propanesultone. This process can be performed both neat and in solvent leading to 26 and 61% loading of sulfonate. This mild procedure was used on a wide variety of aminated MOFs containing different node metals (Zn, Zr, Al) and organic linkers (2-aminoterephtalic acid and benzene tribenzoic acid) to generate sulfonates that would otherwise be difficult to access. Loading of Ir, Pd and Rh cationic catalyst was attempted resulting in improved loading in sulfonated MOFs. Further evaluation of cationic loading into post-synthetically modified MOFs is necessary to elucidate the primary contributed factors for exchange in these materials.

The conduction of electrons and ions is central to the operation of modern technologies. In particular, it is the redistribution of charge within a closed system that enables the production of energy, the storage of information, and the transduction of physicochemical phenomena. Progress on these fronts dictates that underlying component materials also progress towards superior performance and greater specificity in supplying a set of properties tailored to one of an ever growing and nuanced list of applications. Necessarily, new conductive materials must be developed continuously in order to keep up with societal demands for a more electrified and computerized planet. Historically, functional materials reside with a relatively small set of classes: metals, ceramics, glasses, polymers, zeolites, and carbons. While there have been fantastic advances over the last century among every one of these classes, polymers and zeolites stand out as uniquely modern technologies. Synthetic polymers trace back to 1830, with the development of vulcanized rubbers. The advent of synthetic polymers revolutionized the level of control and tunability possible in materials science by leveraging the near infinite structural diversity possible in organic chemistry. It wasn’t until one hundred and twenty years later that synthetic zeolites were commercialized. Zeolites are ceramics that distinguish themselves by their large crystalline void spaces capable of hosting gases and small molecules. Microporous zeolites represented a new competitor to porous carbons, with key advantages of long-range crystalline order and a unique surface chemistry particularly amenable to molecular sieving, gas separations, and the catalytic transformation of commodity chemicals. However, like porous carbons, structural and chemical diversity is limited for zeolites. Today, there are only about 230 known zeolite structures, and the discovery of new zeolite structure types is a notoriously difficult endeavor. More recently a new set of porous crystals has been discovered, metal-organic frameworks. These hybrid materials are particularly well suited to the task of controlling structure and surface chemistry at the atomic level. With both an inorganic component providing the rich structural diversity unique to transition metal coordination chemistry and a prominent organic linker component providing near infinite tunability akin to that of organic polymers, the development of metal-organic frameworks has ignited a renaissance in crystal engineering and porous materials chemistry. Over the last twenty years alone, the structures of many thousands of new metal-organic frameworks have been determined, dwarfing zeolites, carbons, and other porous materials. Further, metal-organic frameworks are steadily proving to be vastly superior in performance across many applications, especially for gas storage and separations. Many obvious implementations of metal-organic frameworks as replacements for zeolites and porous carbons have been widely developed. All the while, the understanding and control of charge transport and electronic communication rested just beyond the horizon. Unlike zeolites and other porous crystals that are exclusively excellent electronic insulators, metal-organic frameworks do not share the same chemical limitations. The possible co-existence of intrinsic porosity, unprecedented structural diversity, intuitive tunability, and long-range electronic communication could fully leverage the potential of this class of materials. That is, the ability to manipulate a bulk electronic structure with precision and dramatic effect may result in new and unpredictable technologies.Yet, it is not without reason that electronically conductive metal-organic frameworks are rare. Electronic communication is strongly dependent upon the relative distances between interacting valence electrons and vanishes steeply with increasing distance. Likewise, ion mobility in crystalline materials also requires extremely short hopping distances, typically less than half a nanometer. Within a class of materials that routinely boast void fractions in excess of 60%, it is not surprising that finding a high density of valence states or ion hopping sites has proven difficult. As such, it is of fundamental interest to explore how these structures can be coaxed into displaying the bulk transport of charge, and the physical means by which it occurs. By first learning the rules of synthesizing conductive metal-organic frameworks and transporting charge therein, it may then be possible to rationally tailor porous conductors for a targeted property or application.To this end, Chapter 1 discusses the nature of ion transport in metal-organic frameworks, its relation to traditional ion conductors, and reviews the prospects of ion conducting frameworks in a number of proposed applications. Surprisingly, though there are many proof-of-concept reports of using metal-organic frameworks in electrochemical devices, the investigation of ion transport is routinely ignored. This is despite it likely being the performance limiting factor in many cases. In fact, many implementations of metal-organic frameworks as component materials in supercapacitor electrodes are predicated on intrinsic porosity translating to fast ion transport. As will be shown, this is decidedly false for many canonical framework materials. Nonetheless, with considerable optimization and targeted selection of pore structure and surface chemistry, it is possible to obtain ionic conductivities high enough to be useful in electrochemical systems. In fact, with judicious selection of host lattice and host-guest interactions it is possible to conduct ions that have been particularly intransigent to bulk transport in traditional materials like ceramics and polymers. Chapter 2 highlights the synthesis of several metal-organic framework-based ion conductors capable of conducting magnesium, demonstrating an alternative strategy for multivalent ion conduction. Discussed in detail are the critical factors that dictate ion insertion and bulk transport in metal-organic frameworks and multiple strategies for maximizing ionic conductivity. With these tools in hand, Chapter 3 tackles mixed electron-ion conductivity in a similarly structured metal-organic framework. In some respects, the interrogation of ion transport in mixed conductors is made easier by the possibility of probing ion transport over a wide range of concentrations, electrochemically measuring the transport of a single ionic species, and directly observing host-guest interactions by changes in electrochemical potential. While many frameworks have been reported as candidate electrodes, Chapter 3 represents the first to thoroughly discuss the role of host-guest interactions, and a surprising sensitivity to changes in the included electrolyte. Finally, Chapter 4 focuses on the modulation of electronic conductivity with host-guest interactions in a non-ionic metal-organic framework. A new technique for interrogating conductivity in porous solids is presented that is based on in-situ gas dosing and the simultaneous determination of conductivity and a gas adsorption isotherm. Unlike previous methods based on vapor exposure at ambient pressure, the measurements reported are referenced to the pure metal-organic framework, which possesses a consistent and well-defined chemical composition. Thus, equilibrium conductivity-composition profiles are directly extracted from the measurement. This is in contrast to the complex and relatively slow exchange reactions that occur by vapor exposure methods, which often lead to results that are difficult to interpret. Thus, a standard method of measuring and reporting the chemresistive response of gaseous and vaporous adsorbates is proposed and demonstrated.

Part 1. Metal-Organic Frameworks (MOFs) have been extensively studied due to their functional versatility and well-defined, porous structures. It is, however, exceptionally rare to find MOFs that use late transition metal complexes as a building block. Incorporation of these complexes would have immediate applications in catalysis and enhanced gas adsorption/storage. Furthermore, because of the MOF’s well-defined structures, heterogeneous catalysis properties can be more readily studied and improved. Herein, 1,2-bis(bi(para-carboxyl)phenylphosphino)benzene palladium dichlo-ride’s (PdCl2(BBCB)) catalytic ability is studied using the Mizoroki-Heck reaction, and 1,2-bis(bi(4-carboxy-biphenyl-4’-phosphino))ethane palladium dichloride (PdCl2(BBCE-1L)) is used to make a MOF with an enlarged pore size and greater catalytic ability. BBCB, a tetra-para-carboxylic acid derivative of dppb, is used to form a palladium dichloride bis(phosphine) complex. This complex was found to perform a Mizoroki-Heck reaction in decent yields despite formation of palladium black. BBCE-1L, a tetra-4-carboxylic acid biphenyl derivative of dppe, was then developed to deter palladium black formation and enlarge the pore size of the MOF. A MOF was made using a Zn(II) paddlewheel as the metal node and PdCl2(BBCE-1L) as the organic linker. This MOF was found to have moderate thermal stability and potentially high pore volume. Part 2. Acid chloride generation is a widely researched field for the synthesis of amides and esters, motifs found throughout nature and pharmaceuticals. Recently, we found that dihaloimidazolidinediones could substitute a variety of alcohols with halogens through an amide-stabilized carbocation. As an extension of this chemistry, we were able to activate most carboxylic acids into the corresponding acid chloride with near quantitative yields. Mechanistic studies of electronic and steric effects suggest that the rate-determining step is the nucleophilic attack of a free chloride ion on the carbonyl center to produce the corresponding acid chloride. Electronic effects of ring size on electrophilicity was also observed and explained through analysis of a simplified Walsh diagram.

Fundamental understanding of atomic-level processes underlying charge separation and transport is critical to the development of next-generation electric energy storage devices to enable wide-scale adoption of electric-vehicle technology and intermittent renewable energy sources (such as wind and solar). Joint Density-Functional Theory (JDFT) allows for the ab initio description of electronic systems in thermodynamic equilibrium with liquid environments and, as such, is ideally positioned to study electrode-electrolyte systems, which are among the most promising technological avenues but which are also currently poorly understood at the fundamental level due to their complexity. This thesis, after describing JDFT and its application to electrochemical environments, focuses on two physical systems of great current research interest in the growing area of supercapacitor storage systems. First, we examine possible sources of an observed but hitherto unexplained enhanced capacitance effect at the Dirac point of graphene in electrolyte environments. We propose and explore two possible explanations for this effect: (1) overscreening by ions within the fluid producing a negative effective fluid capacitance and (2) a stray parallel capacitance effect produced by the adsorption of hydroxide ions. Second, we explore the conduction properties of phthalocyanine-based metal-organic frameworks (MOFs), which represent potential high-performance materials for use as supercapacitors due to their nanoscale structure and high specific surface areas. The challenge here is to increase the electronic conduction of these materials so that the high specific surface area can be accessed as a source of capacitance by an external circuit, and we present detailed calculations of the full electronic conductivity tensor for these materials. The thesis concludes with suggestions for future experimental and theoretical work to advance the understanding of nanoscale influences on charge-storage systems.

An intercalation reaction is the most commonly utilized redox reaction scheme for commercial Li-ion batteries (LIBs) due to minimized crystal deformation during the redox reaction. However, to meet the growing demands for large-scale energy storage criteria, low cost and high energy density, other reaction schemes need to be explored. In order to fully utilize the new schemes, mechanistic understanding of the respective materials is crucial. A relaxation phenomenon facilitates the mechanistic understanding because it inspects both kinetic and thermodynamic products of the reaction. MIL-101(Fe), a MOF material is applied to study the relaxation phenomenon. MIL-101(Fe) demonstrates a unique rate dependent rechargeability. Through X-ray absorption spectroscopy and electronic state calculation, a kinetically stable product and thermodynamically stable product of MIL-101(Fe) are proposed. Kinetically, Fe3+ is reduced upon reduction, however, due to thermodynamic stability, the Fe2+ self oxidizes back to Fe3+ after relaxation. This work demonstrates relaxation phenomenon on the molecular level.Zn electrode is one of the conversion materials with high energy density, yet Zn electrode lacks rechargeability due to the zincate ion formation during oxidation reaction. The zincate ions dissolve into electrolyte making the Zn electrode not rechargeable. One of the ways to overcome this issue is incorporating Bi2O3 as a composite additive. We have added the Bi2O3 additive and identified a comprehensive role of the Bi2O3. Through electron microscopy coupled with energy dispersed X-ray spectroscopy and X-ray photoelectron spectroscopy, we have discovered that the ZnO and Bi2O3 form an intermediate phase that allows zincate ions to deposit and retain ZnO on the electrode surface. This work demonstrates relaxation phenomenon on the particle level. Understanding the relaxation phenomenon upon redox reactions distinguishes the kinetic and thermodynamic products. The findings in this dissertation provide more comprehensive methods to identify the energy storage mechanism. MnO2 is one of the low-cost, environmentally benign, and promising material for energy storage system. A preliminary Mn2+ deposition test suggested that Bi2O3 addition can adhere Mn2+. Based on the knowledge gained through relaxation characterization, a series of characterizations and methods to improve MnO2 aqueous energy storage system are proposed.

Metal-Organic Frameworks (MOFs) are crystalline porous materials constructed of metal ions and organic linkers, and have been widely utilized in gas storage, sensing, and chromatographic separation. The combination of MOF nanoparticles with other materials will broaden the utilization of MOF materials to a great extent. Several approaches for creating composites with the MOF, Zeolitic Imidazolate Framework-8 (ZIF-8), have been developed: dye and model drug molecules were encapsulated in ZIF-8 pores for potential drug delivery; mesoporous silica monolayer was epitaxially grown on the ZIF-8 surface for structural stability enhancement and hollow structure formation; UiO-66, another MOF subclass, was hierarchically encased inside ZIF-8 for double-phase gas separation and heterogeneous catalysis. By exploring the versatile ZIF-8 platform, these nanocomposites could have great applications in fields such as heterogeneous catalysis and drug delivery.

With the principles of reticular chemistry, metal-organic frameworks (MOFs)with enhanced storage and catalytic capabilities have been prepared. This dissertationpresents the synthesis of azo-IRMOF-74-III for controllable release of cargomolecules as well as the catalytic testing of MOF-525-Mn and an isoreticular seriesof MOFs based on the MOF-5 framework. The variation of pore metrics inthese frameworks show the versatility of reticular chemistry and their applicationin catalytic reactions.First, an azobenzene containing MOF-74 analogue was prepared by incorporatingthe azobenezne moiety into the organic linker used to prepare MOF-74.Cargo molecules were trapped inside the structure based on size constraints andcontrollably released via modulation of UV irradiation to induce a trans to cisisomerization on the organic linker. The variation in the linker lengh shows thatspecic cargo molecules can be trapped by changing the size of the one-dimensionalpore in reticular frameworks.In addition to changing pore size, density of catalytic sites inside a pore wasinvestigated through the isoreticular synthesis of a series of MOFs, modeled after MOF-5 but containing various amounts of 2-aminoterephthalic acid. These aminegroups were post-synthetically modied to contain catalytically active Pd sites andheterogeneous Heck coupling was performed. A inverse relationship was observedbetween the amount of framework metalation and reaction yield and selectivity.This is attributed to pore blocking from post-synthetic modication at highermetal loadings.Finally, a manganese porphyrin containing MOF, MOF-525-Mn, was synthesizedand its activity tested through the epoxidation of alkenes using molecularoxygen. High catalytic activity was observed for all alkenes and this is the rstinstance of MOF epoxidation using molecular oxygen, a ubiquitous industrial oxidant.Another MOF containing the same catalytically active porphyrin but in adierent topology, MOF-545-Mn, was also tested for catalytic activity to determinethe eect of MOF topology on heterogeneous catalysis.The variation of pore metrics is demonstrated through each chapter and showhow powerful and useful reticular chemistry is through variation of structuralelements for specic uses. While catalytic MOFs are in their infancy, the future isbright for catalytically active MOFs to come to the forefront of chemical industry.

Employing semi-rigid di-1,2,4-triazoles as ligands has led to the formation of a plethora of Metal-Organic Framework (MOF) architectures. The ability for the ligands to exhibit multiple conformations through a “hinge” effect allows for the formation of a multitude of MOF topologies and dimensionalities. Employment of a di-triazole containing a central trans-butene moiety was initially studied and led to the formation of two three-dimensional copper MOFs. The frameworks can be synthesized independently, but a reaction occurs in water wherein the kinetic product is used as a reagent to synthesize the topologically distinct thermodynamic product. Additional testing of reaction conditions with the butene-containing di-triazole led to the formation of a three-dimensional breathing framework by utilizing a mixed anion system. The framework structure flexes reversibly upon removal or addition of water to form semi-hydrated and dehydrated MOFs. Single crystal X-ray analysis demonstrated the 2-butene subunit of the ligand rotates between positions, causing changes in the solvent accessible volume. This double hinge within the ligand is a built-in breathing mechanism and suggests a general synthesis for breathing MOFs. Replacing the central butene moiety with a xylene moiety resulted in the di-triazole adopting a syn conformation between copper chains, forming two-dimensional MOFs that resemble fused 1D metal-organic nanotubes (MONTs). The 2D sheet layers can expand or contract, or, more remarkably, the phenyl ring can rotate between positions as a function of solvation. The transformations were followed by powder X-ray diffraction and solid state NMR. Additionally, frameworks which contain extended naphthyl and biphenyl linkers have been synthesized and characterized. The syn conformation adopted by the di-triazoles was further exploited for the formation of a series of 1D MONTs. The di-triazole ligands bridge rigid metal chains while appropriate anion choice provides a “capping” of the metal fragments, leading to nanotube formation instead of 2D sheets. The pore size of the MONTs can be adjusted by changing the central portion of the double-hinged ligand, allowing for a general synthesis of MONTs. Adsorption studies of MONTs revealed selective uptake of carbon dioxide and methane with copper MONTs exhibiting the highest uptake.

The adsorption and degradation of methyl parathion an organophosphate with Cu-BTC metal-organic framework (MOF-199) and a polyoxometalate are investigated in multiple fibrous systems. Immobilizing MOF particles in a fibrous system adds functionality to the fibers and allows the MOF particles to be in a workable and flexible substrate. First, a method is presented to immobilize Cu-BTC metal-organic framework (MOF-199) particles by enmeshing them in nonwoven polyacrylonitrile (PAN) nanofibers creating a fibrous membrane with the potential ability to remove chemical warfare agents or pesticides from solution. These membranes were shown to effectively adsorb methyl parathion, an organophosphate pesticide. Based on solubility theory and experimental results, partitioning was determined to be the main mechanism of removal. After 2 hours, the PAN/MOF-199 membranes removed 88% more methyl parathion than the unmodified PAN membranes and 62% as much as the MOF-199 crystal powder. Further experiments revealed that degradation of methyl parathion was occurring within the MOF cages. Degradation of methyl parathion adsorbed in metalorganic framework (MOF)-199 cages was studied using nuclear magnetic resonance (NMR), Raman spectrometry, and solvent extractions. NMR was completed using solid-state 31 P NMR with magic-angle spinning with cross polarization or direct polarization. Results show that constitutional isomerization is the main mechanism of methyl parathion degradation within the MOF-199 framework within the 5-67 day time frame studied. Secondly, A combination of a Keggin-type polyoxometalate (POM), [CuPW11O39]5-, with a metal-organic framework (MOF), MOF-199 (HKUST-1) was successfully self-assembled on a cellulose substrate (cotton) with a newly developed room-temperature process. This material was found to effectively remove 2.75 times as much of a target organophosphate toxin, methyl parathion, from a hexane solution as MOF-cotton and cotton control samples after 2 h. The combination of the catalytic activity of the POM and the adsorption properties of the MOF both immobilized on a textile is ideal for potential applications in protective self-decontaminating materials. In addition to this, hydrophilicity of the fabrics is maintained, which leads to a material that maintains the thermal comfort of cotton. The functionalized fibrous PAN/MOF-199 membranes also have potential to be used in protective clothing for occupational or military applications or as filtration media.

Metal-Organic Frameworks, or MOFs, are crystalline materials consisting of metal ions or clusters coordinated to often rigid or flexible organic linkers to form two- or three-dimensional structures. MOFs can be porous, and the voids within the MOFs can host other molecules such as solvents or gases. A current and newly explored area of MOFs involves the reaction of magnesium salts with different carboxylates. These specific MOFs can have good stability to adsorb and desorb gases at higher temperatures. Solvothermal synthesis is the method used to produce these frameworks; however other methods have been tested and reported. Also the syntheses can be environmentally friendly, using less harmful chemicals to produce the products, and require little to no work up considering the products contain almost no impurities. Once the frameworks are produced it is applicable that they be connected to a planar substrate for further commercial use. By using reactive seeding and other methods there are several different ways that MOFs can be attached to a support. The specific aim of this project is to develop novel magnesium metal-organic frameworks, characterize them and then test their adsorption properties for different types of gases.

To date, there has been no comprehensive attempt to perform and/or describe catalytic reactions in the gas phase that utilize metal-organic frameworks (MOFs) as catalysts. In addition, there has been no attempt to reaction engineer these MOF catalysts in order to determine their regimes of optimal catalytic activity and possible limitations to their use. A zinc-based MOF that has been post-synthetically modified with a homogeneous palladium catalyst, Pd(CH3CN)2Cl2, is used to catalyze the hydrogenation of propylene. The catalyst is assembled in a packed-bed reactor under a continuous flow of reactants. The reaction is optimized with respect to isoreticular metalation, reactant flow rate, and reactor temperature. Maximum catalytic conversion is found at intermediate metalations of 40% and 60%, high hydrogen flow of 50 ccm, and intermediate reactor temperatures of 100 °C and 150 °C.The MOF-60 catalyst is exposed to a traditional catalyst poison, carbon monoxide (CO). It is found that the MOF is reversibly poisoned upon introduction of CO. Upon poisoning, catalytic conversions rates of 90%-100% are dramatically reduced to less than 10%-30%, depending on the CO flow rate and the reactor temperature. The CO poisoning is shown to be reversible, a similar effect as found with palladium on carbon (Pd/C). The time scale of poisoning and recovery is very fast for both the MOF catalyst and Pd/C (approximately 10-30 seconds). Other effects of temperature on the MOF-40 are also investigated. At fixed reactant flow, the temperature grid is partitioned into finer steps of 10 °C to determine the temperature that yields the highest catalytic conversion. It is found that conversion is nearly uniform in the range between the highest conversions, i.e., conversion plateaus between the optimum temperatures. The catalyst also exhibits a weak thermal hysteresis. There is no significant improvement in conversion with thermal cycling after alternating the reactor temperature between 100 °C and 200 °C for 8 hours.

The separation of carbon dioxide from natural gas is of great interest from the environmental and energy perspective, respectively. From the environmental point of view, capturing CO2 effectively from power plants can have a positive impact on reducing greenhouse gas emissions. From the energy point of view, CO2 is an undesirable impurity in natural gas wells, with concentrations as high as 70%. Membrane technology can play a major role in making natural gas purification processes economically feasible. A novel membrane composed of Metal-organic-framework material Zn8(Ad)4(BPDC)6O 2Me2NH2 (Bio-MOF-1) was designed and created to effectively separate CO2/CH4 gas mixtures. The crystalline structure, composition, and textural properties of Bio-MOF-1 membranes were confirmed through x-ray diffractometry, CHN analysis, transmission electron microscopy, adsorption measurements and BET surface area. A secondary seeded growth approach was employed to prepare these membranes on tubular stainless steel porous support. These membranes displayed high CO2 permeances (11.5x10-7 mol/m2 s Pa) and moderate CO2/CH4 separation selectivities (1.2-2.5). The observed selectivities are above the Knudsen selectivity and indicate that the separation is promoted by preferential CO2 adsorption over CH4. This preferential adsorption is attributed to the presence of adeninate amino basic sites present in the Bio-MOF-1 structure. The work demonstrated shows the feasibility of the development of a novel type of membrane that could be promising for diverse molecular gas separations.

The likelihood of fossil fuel power plants being targeted for future CO2 emissions regulation creates a motivation for developing an alternative CO2 capture method that is more sustainable and less energy intensive than the current approach using amine solvents. A special class of metal-organic framework adsorbents known as elastic layered metal-organic frameworks (ELM) exhibit a step-like CO2 adsorption isotherm that offers intriguing advantages for CO2 capture applications in comparison to other proposed carbon capture adsorbents with Langmuir-like adsorption isotherms. Molecular simulations and experiments were therefore carried out to explain the adsorption phenomena observed for ELM material and assess the suitability of ELM adsorbents for CO2 capture from flue gas and synthesis gas mixtures. The hybrid osmotic Monte Carlo (HOMC) simulation methodology developed as a part of this work, for the first time has provided atomistic insights into the mechanism leading to the expansion of the material and CO2 isosteric heat of adsorption profiles. The adsorption-induced expansion was shown to depend on the CO2 orientation transition and the interplay of the CO2-framework configuration, to increase CO2-CO2 interaction energy by 1.6 kJ/mol compared to the pre-expansion state. Predicted CO2 selectivities (from 44 to 600 with different temperatures and pressures) are comparable to those typically observed with other microporous materials that have been proposed as carbon capture adsorbents (typically from 3 – 1000). In addition, the CO2 isosteric heat of adsorption of ELMs are moderate (23 – 28 kJ/mol) compared to other current adsorbents (30 – 45 kJ/mol). Structure-function relationships established for this series of ELM adsorbents shows that the gate pressure is to follow the metal vertex trend Cu2+ < Co2+ < Ni2+ from lowest to highest gate pressure for ELM framework series investigated in this work, containing BF4- and CF3SO3- as the anions. Results of the study show that ELM materials possess important features of an effective carbon capture adsorbent such as high CO2 selectivity, moderate CO2 heat of adsorption. Broadly speaking, the simulation results and experimental studies reported in this work support the conclusion that ELM adsorbents have the requisite material properties to merit further consideration as carbon capture adsorbents.

Crystalline microporous coordination polymers (MCPs) are ordered, porous materials that have recently seen increasing attention in the literature. Whereas gas phase separations using MCPs have been extensively studied and reviewed, studies on applications in the liquid phase, particularly from complex matrices, have lagged behind. In this thesis, MCPs have been applied to adsorption from diesel and water. The utility of MCPs for the adsorption of large organosulfur compounds (benzothiophene, dibenzothiophene, 4,6-dimethyldibenzothiophene) found as pollutant precursors in fuels was demonstrated. Large capacities were obtained, particularly for 4,6-dimethyldibenzothiophene, the compound most difficult to remove using current industrial techniques. It was determined that the size/shape of the pores in the MCP, rather than surface area or pore volume, is the most important factor controlling adsorption capacity. This was confirmed by studying the supramolecular isomers University of Michigan Crystalline Material (UMCM)-152 and UMCM-153 which exhibited different adsorption behaviors. Electron-deficient MCPs were also tested and higher adsorption capacities were observed for the most electron-deficient structure. MCPs were demonstrated to be efficient adsorbents for the removal of the organosulfur compounds dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from model fuel and diesel fuel in packed bed breakthrough experiments. Unlike activated carbons, where selectivity has been a problem, MCPs selectively adsorb the organosulfur compounds over similar components of diesel. Complete regeneration using toluene at modest temperatures was achieved. The attainment of high selectivities and capacities, particularly for the adsorption of the difficult to remove refractory compounds, in a reversible sorbent indicates that fuel desulfurization may be an important application for MCPs. Finally, the water stability of a variety of MCPs was studied using powder X-ray diffraction. It was determined that the stability of the MCP is related to the metal cluster present in the structure with trinuclear chromium clusters more stable than copper paddlewheel clusters which are more stable than basic zinc acetate clusters. Matériaux de l’Institut Lavoisier (MIL)-100 was found to be completely water stable and was used to adsorb the pharmaceuticals furosemide and sulfasalazine from water with large uptakes at low concentrations, indicating that the adsorption of wastewater contaminants may be a feasible application for these materials.