In the first section, the electrical conductivity of rhodium phenylene-diisocyanide polymer is reported to be 3.4E-11 S/cm. However, the conductivity also exhibits an inverse exponential decay in air with t = 8 days. This change is attributed to the oxidation of the isocyanide functional group to an isocyanate, leading to degradation in the long-range metal-metal bonding, the dominant conductivity mechanism. Using a more stable carboxylate ligand, the Cu terephthalate (TPA) system is studied and compared against the Mg, Co, Ni, and Zn terephthalates. A synthesis in N,N-dimethylformamide (DMF) is developed and large quantities of the Cu(TPA)DMF can be synthesized in air. The crystal structure of the Cu(TPA) DMF is shown to be in the C2/m spacegroup. Upon desolvation, the Cu(TPA) is shown to have a large surface area of 625 m2/g. The magnetic susceptibility of the Cu(TPA) indicates anti-ferromagnetic coupling between adjacent Cu centers in the same dimer. The thermal stability of the Zn, Ni, Co, and Mg terephthalates is shown to increase with decreasing symmetric carboxylate stretch in the IR. The magnetic susceptibilities of the Co and Ni terephthalates have paramagnetic behavior, with a Weiss temperature of T = -12.9 K and T = 8.8 for Co(TPA) DMF and Ni(TPA)DMF respectively. A heterometallic Zn-Cu terephthalate is synthesized with Cu concentrations ranging from 0 to 100%. Upon the addition of Cu, Zn-rich frameworks increase in surface area, change in thermal stability, and increase their solvent retention from 16% to 25%. Zn is shown to couple with Cu in the same dimer at a high rate, changing the behavior of the dimer from anti-ferromagnetic to paramagnetic. The Weiss temperature suggests weak ferromagnetic interaction.

Submitted by ELAINE CRISTINA MUNIZ null (elainecris7@yahoo.com.br) on 2016-03-11T12:09:12Z No. of bitstreams: 1 ELAINE CRISTINA MUNIZ-tese.pdf: 10917322 bytes, checksum: bd6553f5a382221f4d18db6600416bcb (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-03-14T18:09:48Z (GMT) No. of bitstreams: 1 muniz_ec_dr_araiq_par.pdf: 726928 bytes, checksum: c405502c64aca6bda28f96dbbfbca30f (MD5) / Made available in DSpace on 2016-03-14T18:09:48Z (GMT). No. of bitstreams: 1 muniz_ec_dr_araiq_par.pdf: 726928 bytes, checksum: c405502c64aca6bda28f96dbbfbca30f (MD5) Previous issue date: 2016-02-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Materiais luminescentes despertam grande interesse nas pesquisas devido à variedade de aplicações, podendo ser empregados em displays eletrônicos, lâmpadas fluorescentes e diodos emissores de luz, por exemplo. Neste contexto, os íons lantanídeos trivalentes são destaque pois apresentam propriedades luminescentes únicas como alta pureza de cor, tempo de vida de nano a milissegundos e linhas de emissão definidas e estreitas provenientes de transições intraconfiguracionais 4f-4f. No entanto, devida à natureza proibida dessas transições, os íons lantanídeos apresentam baixa absortividade molar. Para suprir essa deficiência, pode ser realizada a coordenação destes íons com bons grupos cromóforos capazes de transferir energia para os níveis 4f dos lantanídeos. Outra estratégia para melhorar as propriedades luminescentes de materiais é através da combinação e/ou dopagem utilizando diferentes lantanídeos, o que pode resultar na emissão de ambos os íons ou na emissão preferencial de um deles por meio de processos de transferência de energia. Espécies bimetálicas heteronucleares e polímeros de coordenação porosos (Metal Organic Frameworks, MOFs) se destacam neste cenário. Neste trabalho foram estudadas quatro séries de compostos bimetálicos heteronucleares utilizando succinato de sódio e ácido 3,5-dicarbóxipirazolico como ligantes e variando a razão entre dois íons lantanídeos distintos, Gd3+:Eu3+, Gd3+:Tb3+, Dy3+:Eu3+ e Eu3+:Tb3+. Os compostos obtidos foram caracterizados por difração de raios X de monocristal e de pó, espectroscopia na região do IV, análise térmica, espectroscopia de reflectância difusa, espectroscopia de fotoluminescência com excitação UV, luminescência com excitação por raios X e microscopia eletrônica de varredura associada à espectroscopia por energia dispersiva. Os complexos apresentaram interessantes propriedades luminescentes. Para as séries de compostos contendo íons Gd3+, quanto maior a quantidade de Gd3+, maior a intensidade da banda relativa à transferência de carga do ligante para o metal, indicando que os íons Gd3+ possuem um papel importante no mecanismo de transferência de energia do ligante para os lantanídeos emissores. Foram calculados os parâmetros de intensidade, as taxas de decaimento radiativo e não-radiativo e a eficiência quântica para a série Gd3+:Eu3+, que apresentaram baixa eficiência quântica, devido principalmente à supressão da luminescência pelas moléculas de água presente na estrutura. Os compostos da série Dy3+:Eu3+ não apresentam transferência de energia entre os lantanídeos e só foi possível observar a emissão dos dois íons ao mesmo tempo quando a excitação é realizada no ligante ou quando se utilizou raios X para a excitação. Já na série Eu3+:Tb3+, observou-se transferência de energia apenas dos íons Tb3+ para os íons Eu3+. O oposto não foi verificado. Os espectros de emissão dessa série registrados em diferentes temperaturas mostram que os compostos Eu3+:Tb3+ possuem potencialidade para aplicação como termômetro molecular na faixa de temperatura entre -80 e 25°C. Foram realizadas três sínteses diferentes para preparação dos MOFs. Os compostos obtidos apresentam intensidade de emissão e eficiência quântica elevadas. Além disso, a estabilidade térmica dos compostos é evidência de que os compostos obtidos podem ser de fato MOFs. / Luminescent materials attract interest in research due to the diversity of applications. These materials can be used at electronic displays, fluorescent lamps and light emitting diodes, for example. In this context, trivalent lanthanide ions are interesting because of their unique luminescent properties like high color purity, nano to milliseconds lifetime and narrow emission lines from 4f-4f transitions. However, because of the nature of forbidden 4f-4f transitions, lanthanide ions have low molar absorptivity. To supply this deficiency, the lanthanide ions can be coordinated to chromophore groups, capable of transfer energy to the 4f levels of lanthanides. It is also possible to improve the luminescent properties of materials by combining different lanthanides, which can result in the emission of both ions or in the preferential emission of one of them by energy transfer processes. Bimetallic heteronuclear complexes and metal organic frameworks (MOFs) are interesting in this context. In this work, four bimetallic heteronuclear compounds series with sodium succinate and 3,5- dicarboxypyrazolate ligands were prepared with different lanthanides ratio, Gd3+:Eu3+ , Gd3+:Tb3+, Dy3+:Eu3+ e Eu3+:Tb3+ . The compounds were characterized by single crystal and powder X-ray diffraction, Fourier transform infrared spectroscopy, thermal analysis, UV-Vis spectroscopy, photoluminescence spectroscopy, X-ray excited optical luminescence and field emission gun-scanning electron microscopy, with energy dispersive X-ray spectroscopy. The complexes present interesting luminescent properties. In Gd3+ compounds series, by increasing the amount of Gd3+ ions in the sample, the intensity of the relative charge transfer band also increases, indicating that the Gd3+ ions play an important role in the energy transfer mechanism from ligands to the lanthanides. The intensity parameters, the radiative and non-radiative decay rates and the quantum efficiency were calculated to Gd3+:Eu3+ series, which showed low quantum efficiency due to luminescence quenching by water molecules in the structure. The Dy3+:Eu3+ compounds does not show energy transfer between the lanthanides ions and the emission from both ions was observed simultaneously only under excitation at the ligand absorption or under X-rays excitation. In the Eu3+:Tb3+ series, the energy transfer was observed only from Tb3+ ions to the Eu3+ ions. The opposite was not verified. The emission spectra of the Eu3+:Tb3+ compound recorded at different temperatures show that this series compounds present potential to be applied as molecular thermometer in the range of -80 to 25 °C. Three different syntheses were performed to prepare MOFs. The obtained compounds exhibit high emission intensity and good quantum efficiency. Furthermore, the thermal stability of the compounds is evidence to propose that the obtained compounds is indeed MOFs. / CNPq: 141262/2012-5

Les porphyrines sont des composés macrocycliques naturels étudiés de manière approfondie en tant que mimétiques enzymatiques ou catalyseurs d'oxydation en milieu homogène. L'incorporation de porphyrines dans des réseaux de polymères de coordination métal-organique (MOFs), qui constituent une famille de composés cristallins poreux connus pour leur diversité structurelle, pourrait conduire à des matériaux constitués de réseaux étendus présentant les mêmes propriétés que les systèmes homogènes. Toutefois de nombreux travaux ont montré que la limitation majeure pour des applications à grande échelle des MOFs est leur stabilité.La stabilité de ces matériaux peut être accrue en employant des cations métalliques de valence élevée dans l'unité de construction inorganique (tels que Fe3+, Al3+, Zr4+) et / ou en modifiant la fonction coordinante du ligand organique.Ce travail est relatif à l'étude de la réactivité de ligands porphyriniques portant diverses fonctions coordinantes, avec des ions métalliques de valence élevée. L'influence des paramètres de synthèse et la caractérisation approfondie de ces MOFs ont été réalisées par une combinaison de techniques expérimentales (diffraction des rayons X, analyse thermogravimétrique, spectroscopie UV-vis, spectroscopie infrarouge, études de sorption, etc.). Dans un premier temps, l'étude s'est focalisée sur des MOFs porphyriniques à base de groupements carboxylates stables connus, ce qui a conduit à de nouvelles variantes de ces matériaux. Dans un second temps il est démontré que les topologies des réseaux observées sur un ligand porphyrinique à base carboxylate peuvent être étendues à d'autres fonctionnalités avec la synthèse d'un nouveau MOF à base de tétrazolate. L'amélioration de la stabilité a également été explorée avec des ligands portant des fonctions phénol qui ont abouti à l'élaboration de nouveaux réseaux de coordination. La synthèse et l'étude de stabilité d'un MOF porphyrinique à base de gallate est rapportée. L'évaluation préliminaire de l'activité catalytique de certains des MOFs élaborés est également décrite / Porphyrins are important macrocyclic compounds which are prevalent in nature and have been extensively studied by chemists in homogeneous catalysis as enzyme mimics. Incorporating porphyrins in metal-organic frameworks (MOFs) offer an ideal opportunity to obtain material with extended frameworks possessing the same properties as the homogenous systems. Much work has been done on porphyrinic MOFs but their stability remains a problem and a major limitation for possible wide scale applications. In literature, more stable MOFs have been realised using high valent metal ions in the inorganic building unit (such as Fe3+, Al3+, Zr4+) and/or by using more basic functionalities in the organic linker. However, regarding porphyrinic MOFs, little work is reported with ligands based on functionalities other than carboxylic acid groups. Therefore, our work focused on investigating the reactivity of porphyrinic ligands carrying various functionalities with high valent metal ions. More precisely, we focused on the design, synthesis optimisation and characterisation of such materials. This included studying existing stable carboxylate porphyrinic frameworks with a goal of incorporating new functionalities, which led to new variations of these materials. Our work also demonstrated that the framework topologies observed with carboxylate based porphyrinic ligand can be expanded to other functionalities with the synthesis of a new tetrazolate based porphyrinic MOF. MOF synthesis was also investigated with phenolate functionalised ligands and resulted in the first gallate based porphyrinic MOF reported. The stability of this new material was assessed. This manuscript discusses the synthesis and the characterisation of these MOFs via a combination of experimental techniques (X-ray diffraction, TGA analysis, UV-vis spectroscopy, IR-spectroscopy, sorption studies etc.). The preliminary evaluation of the catalytic activity of some of the MOFs is also described

Due to their high surface areas and structural tunability, porous metal-organic materials, MOMs, have attracted wide research interest in areas such as carbon capture, as the judicious choice of molecular building block (MBB) and linker facilitates the design of MOMs with myriad topologies and allows for a systematic variation of the pore environment. Families of MOMs with modular components, i.e. MOM platforms, are eminently suitable for targeting the selective adsorption of guest molecules such as CO2 because their pore size and pore functionality can each be tailored independently. MOMs with saturated metal centers (SMCs) that promote strong yet reversible CO2 binding in conjunction with favorable adsorption kinetics are an attractive alternative to MOMs containing unstaurated metal centers (UMCs) or amines. Whereas MOMs with SMCs and exclusively organic linkers typically have poor CO2 selectivity, it has been shown that a versatile, long known platform with SMCs, pillared square grids with inorganic anion pillars and pcu topology, exhibits high and selective CO2 uptake, a moderate CO2 binding affinity, and good stability under practical conditions. As detailed herein, the tuning of pore size and pore functionality in this platform has modulated the CO2 adsorption properties and revealed variants with unprecedented selectivity towards CO2 under industrially relevant conditions, even in the presence of moisture. With the aim of tuning pore chemistry while preserving pore size, we initially explored the effect of pillar substitution upon the carbon capture properties of a pillared square grid, [Cu(bipy)2(SiF6)] (SIFSIX-1-Cu). Room temperature CO2, CH4, and N2 adsorption isotherms revealed that substitution of the SiF62- (“SIFSIX”) inorganic pillar with TiF62- (“TIFSIX”) or SnF62- (“SNIFSIX”) modulated CO2 uptake, CO2 affinity (heat of adsorption, Qst), and selectivity vs. CH4 and N2. TIFSIX-1-Cu and SNIFSIX-1-Cu were calculated to exhibit the highest CO2/N2 and CO2/CH4 adsorption selectivites of the series, respectively. Modeling studies of TIFSIX-1-Cu and SIFSIX-1-Cu suggested that the enhancements in low pressure CO2 uptake and CO2 selectivity in the former arose from the stronger polarization of CO2 molecules by TIFSIX-1-Cu. The stronger framework-CO2 interaction at the primary binding site in TIFSIX-1-Cu correlates with the greater electronegativity of the pillar fluorine atoms relative to those in SIFSIX-1-Cu, and in turn to the higher polarizability of Ti4+ vs. Si4+. The effect of tuning pore size upon the carbon capture performance of pillared square grid nets was next investigated. Linker substitution afforded three variants, SIFSIX-2-Cu, SIFSIX-2-Cu-i, and SIFSIX-3-Zn, with pore sizes ranging from nanoporous (13.05 Å in SIFSIX-2-Cu) to ultramicroporous (3.84 Å in SIFSIX-3-Zn). Single-gas adsorption isotherms showed that SIFSIX-2-Cu-i, a doubly interpenetrated polymorph of SIFSIX-2-Cu with contracted pores (5.15 Å), exhibited far higher CO2 uptake, Qst towards CO2, and selectivity towards CO2 vs. CH4 and N2 than its non-interpenetrated counterpart. Further contraction of the pores afforded SIFSIX-3-Zn, a MOM with enhanced CO2 binding affinity and selectivity vs. SIFSIX-2-Cu-i. Remarkably, the selectivity of SIFSIX-3-Zn towards CO2 was found to be unprecedented among porous materials. Equilibrium and column breakthrough adsorption tests involving gas mixtures meant to mimic post-combustion carbon capture (CO2/N2), natural gas/biogas purification (CO2/CH4), and syngas purification (CO2/H2) confirmed the high selectivities of SIFSIX-2-Cu-i and SIFSIX-3-Zn. Gas mixture experiments also revealed that SIFSIX-3-Zn exhibited optimal CO2 adsorption kinetics. Most importantly, the CO2 selectivity of SIFSIX-2-Cu-i and SIFSIX-3-Zn was minimally affected in the presence of moisture. Modeling studies of CO2 adsorption in SIFSIX-3-Zn (experimental Qst ~ 45 kJ/mol at all loadings) revealed strong yet reversible electrostatic interactions between CO2 molecules and the SIFSIX pillars lining the confined channels of the material. Porous materials based upon the non-covalent assembly of discrete MBBs can also exhibit high surface areas and systematically tunable pore environments. Molecular porous material (MPM) platforms have begun to emerge despite the greater challenge of designing such materials in comparison to MOMs. Herein we report the tuning of pore functionality in an MPM platform based upon an extensive hydrogen-bonded network of paddlewheel-shaped [Cu(ade)4L2] complexes (ade = adenine; L = axial ligand). The substitution of Cl axial ligands with inorganic TIFSIX moieties has produced [Cu2(ade)4(TiF6)2], MPM-1-TIFSIX, a variant with enhanced CO2 separation performance and stability. Single-gas adsorption isotherms reveal that MPM-1-TIFSIX exhibits the highest CO2 uptake and CO2 Qst yet reported for an MPM as well as high selectivity towards CO2 vs. CH4 and N2. Modeling studies indicated strong electrostatic interactions between CO2 and the TIFSIX ligands lining the pores of MPM-1-TIFSIX. In addition to dramatically surpassing MPM-1-Cl with regard to CO2 separation performance, MPM-1-TIFSIX exhibits thermal stability up to 568 K and retains its performance even after immersion in water for 24 hrs. Comprehensively, the results presented herein affirm that porous materials featuring inorganic anions and SMCs can exhibit high and selective CO2 uptake, sufficient stability, and facile activation conditions without the drawbacks associated with UMCs and amines, i.e. competitive water adsorption and high regeneration energy, respectively.

Mes travaux de thèse ont porté sur les matériaux hybrides organiques-inorganiques (MOFs) qui constituent une nouvelle classe de matériaux cristallins et nanoporeux, formés de centres métalliques interconnectés par des ligands organiques, dont les applications pour la séparation de gaz d'intérêt industriel ou la catralyse sont très prometteuses. Je me suis particulièrement intéressée aux Soft Porous Crystals, qui présentent une flexibilité structurale de grande amplitude en réponse à des stimuli externes tels que la température, la pression mécanique ou l'adsorption de molécules. Afin de mieux comprendre la très large gamme des comportements observés pour la flexibilité des MOFs, j'ai développé au cours de ma thèse une méthodologie complète de ces matériaux en combinant différentes méthodes de simulation moléculaire classique et quantique.Dans un premier temps, j'ai étudié les propriétés mécaniques de ces nouveaux matériaux flexibles dans le régime élastique. J'ai identifié la signature élastique des SPC et mis en évidence l'origine microscopique de la flexibilité structurale de ces matériaux hybrides. Ensuite j'ai étudié la stabilité mécanique de ces matériaux en fonction de la température, de la pression mécanique et de l'adsorption de molécules. Et notamment au phénomène d'amorphisation sous pression et au polymorphisme induit par l'intrusion de fluide de certaines MOFs. Dans un dernier temps, j'ai étudié l'influence de la géométrie, de la topologie structurale et de la fonctionnalisation des matériaux de la famille des ZIFs sur leurs propriétés d'adsorption d'eau. J'ai alors montré comment les propriétés d'hydrophobicité de ces matériaux peuvent être modulées. / The topic of this thesis is the thermodynamical, mechanical and adsorptive behavior of Soft Porous Crystals (SPCs). Porous metal-organic frameworks (MOF) are a novel class of crystalline materials with promising industrial applications such as gas adsorption and separation processes. The Soft Porous Crystals feature dynamic frameworks displaying reversible structural deformations of large amplitude in response to external physical constraints such as temperature, mechanical pressure or gas adsorption. I have developed a new methodology based on classical and quantum calculations in order to study these flexible metal-organic frameworks. I first studied the mechanical properties of different SPCs in order to link the local elastic behaviour of these materials and the structural flexibility. These results shed light onto the microscopic origin of stimuli-induced structural transitions in flexible MOFs, showing that the framework flexibility and existence of structural transition are clearly visible in their local elastic propertiesThen, I looked the mechanical stability of hybrid organic-inorganic frameworks under mechanical pressure and gas adsorption. In particular, I studied the pressure-induced amorphization of ZIF-8 and the polymorphism phenomenon induced by fluid intrusion. Finally, I was interested in the impact of geometry and functionalization on water adsorption properties of zeolitic imidazolate frameworks (ZIFs). I demonstrated how topology, geometry, and linker functionalization drastically affect the water adsorption properties of these materials, tweaking the ZIF materials from hydrophobic to hydrophilic.

M.Sc. (Chemistry) / Please refer to full text to view abstract

Ce travail a concerné la synthèse hydro-solvothermale et la caractérisation de nouveaux fluorures hybrides à porosité variable, dans l’objectif à terme de tester ces matériaux poreux en stockage ou purification de gaz. En première partie, l’aminotétrazole a été utilisé comme ligand organique et a permis de mettre en évidence douze nouveaux fluorures hybrides, dont six sont de type MOF. Plusieurs paramètres de synthèse ont été identifiés comme cruciaux dans la condensation d'édifices ouverts. C’est, en particulier, la température, la composition du milieu ainsi que la nature des cations métalliques (Zn2+/Fe3+, Fe2+/Fe3+ et Zn2+ seul) et du solvant. Les porosités estimées de ces MOF atteignent 25% en volume bien que la taille de l’aminotétrazole soit réduite. En seconde partie, des ligands plus étendus à noyaux tétrazoliques multiples ont été choisis afin de parvenir à augmenter la dimension des cavités des MOFs. Ces molécules, non commercialisées, ont été synthétisées dans un premier temps puis impliquées dans l’élaboration de nouveaux hybrides. Alors que la molécule H3btt à 3 noyaux tétrazole n’a pas abouti à des résultats, H2bdt a conduit à de nouvelles architectures fluorées en présence de Zn et/ou Fe. Deux d’entre elles, [Hdma]∙(FeIIF(bdt)) et FeIIF(Hbdt), présentent des porosités remarquables de 40 et 60% qui s’approchent de celles des matériaux de référence. / This work focuses on the hydro-solvothermal synthesis and the characterization of new hybrid fluorides with tunable porosity, with the aim of testing new porous materials for gas storage and purification. In the first part, the aminotetrazole was used as organic linker and twelve new hybrid fluorides were evidenced, six phases belong to MOFs class. Several parameters were identified as crucial for the condensation of open frameworks, in particular, the temperature, the medium composition as well as the nature of metallic cations (Zn2+/Fe3+, Fe2+/Fe3+ or only Zn2+) and of the solvent. The porosity of these MOFs reaches 25% of volume, in spite of the small size of the aminotetrazole molecule. In the second part, polytetrazoles linkers with extended size were chosen, in order to increase the size of MOFs cavities. Non-commercial molecules were prepared and applied to the elaboration of new hybrids. While H3btt with 3 tetrazole cycles did not provide any expected result, H2bdt led to new fluorinated architectures in the presence of Zn and/or Fe. Two phases, [Hdma]∙(FeIIF(bdt)) and FeIIF(Hbdt), exhibit remarkable porosities of 40 and 60%, values.

In this dissertation, investigations regarding magnetism within metal-organic frameworks (MOFs) based on calculations in the framework of density functional theory (DFT) were carried out. On the one hand, the intrinsic magnetic properties within the MOF DUT-8(Ni) were studied (DUT -- Dresden University of Technology). This MOF is flexible, thus it can exist in two crystal structures named DUT-8(Ni)ppen and DUT-8(Ni)closed. A transition from one structure to the other can be achieved via e.g. gas adsorption, leading to a volume increase of approximately 260 %. The magnetic properties originate from spin-spin interactions between the unpaired electrons at the Ni centers. The magnetic coupling between the Ni ions was found to be low-spin (antiferromagnetic). Considering that MOFs tend to have rather large unit cells (> 100 atoms), model systems (< 30 atoms) were generated. Such models can qualitatively as well as quantitatively describe the coupling inside the crystal structure while drastically reducing computational time. Furthermore, the model systems can be easily altered e.g. to introduce defects. The influence of these alterations on the magnetic coupling was studied. In addition, the metal centers have been exchanged by other 3d-metals to analyze the coupling constant with respect to different magnetic centers. On the other hand, the magnetic shielding of Xe adsorbed into the MOFs UiO-66 and UiO-67 was investigated (UiO -- University of Oslo). Based on high-pressure nuclear magnetic resonance (NMR) measurements, which showed a decrease of the total chemical shift when going from the smaller MOF (UiO-66) to the larger one (UiO-67), a thorough theoretical analysis was carried out. For this purpose the ansatz of Ito and Fraissard, i.e. the chemical shift of Xe being a sum of different contributions, was employed. Accordingly, model systems which describe the influences of the MOFs and adjacent Xe atoms on the magnetic shielding were contructed. After equilibrating the Xe positions using molecular dynamics simulations, these model systems were taken to study the chemical shift of all Xe atoms individually. Thus, an analysis of the chemical shift inside each pore of the MOFs was carried out. This allows a description of different influences (Xe-surface, Xe-Xe) on the chemical shift, explaining the experimental behavior at an atomistic level.

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

The emerging field of nanomaterials has raised a number of fascinating scientific questions that remain unanswered. Molecular theory and computer simulation are key tools to unlocking future discoveries in materials science, and various computational techniques and results toward this goal are elucidated here. High-performance computing methods (utilizing the latest supercomputers and codes) have been developed to explore and predict the chemistry and physical properties of systems as diverse as Metal-Organic Frameworks, discrete nanocubes, photoswitch molecules, porphyrins and several interesting enzymes. In addition, highlights of fundamental statistical physics, such as the Feynman-Hibbs effective partition function and generalized ensemble theory, are expounded and upon from the perspective of both research and pedagogy.