Submitted by Pedro Barros (pedro.silvabarros@ufpe.br) on 2018-07-19T22:53:08Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Guilherme de Coimbra Santos.pdf: 6601677 bytes, checksum: 98f83ae5c0517751b976e593f82b4003 (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-07-20T21:39:55Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Guilherme de Coimbra Santos.pdf: 6601677 bytes, checksum: 98f83ae5c0517751b976e593f82b4003 (MD5) / Made available in DSpace on 2018-07-20T21:39:55Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Guilherme de Coimbra Santos.pdf: 6601677 bytes, checksum: 98f83ae5c0517751b976e593f82b4003 (MD5) Previous issue date: 2017-02-15 / CNPQ / Este trabalho apresenta a síntese da já conhecida MOF [Zn2(BDC)2(dpNDI)]n (BDC = 1,4-benzenodicarboxilato, dpNDI = N’N’-di(4-piridil)-1,4,5,8-naftalenodiimida), mas, agora dopada em diferentes percentagens (0,1%, 0,5%, 1%, 2% e 5%) com o íon európio (íon sonda), por via solvotermica. Após suas caracterizações, observam-se respostas espectroscópicas, frente à monoaromático, favoráveis na identificação de moléculas hóspedes. A síntese e caracterização de redes de coordenação cristalinas, bem como de compósitos a base de carvão ativado, a partir de íons lantanídeos (Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Dy³⁺, Er³⁺, Tm³⁺ e o Yb³⁺) com emprego do ligante flexível, succinato, utilizando-se a técnica hidrotermal para obtenção desses sistemas, foram realizadas, além de investigações de sistemas mixmetal nessa mesma matriz carbonácea. Novos compósitos porosos LnBDC@CA (CA = Carvão ativado, Ln = Pr³⁺; Nd³⁺; Sm³⁺; Eu³⁺; Gd³⁺; Er³⁺; Tm³⁺ e Yb³⁺ e BDC = 1,4benzenodicaboxilato) e CB[6]@CA (CB[6] = Cucurbit[6]uril) foram obtidos utilizando via hidrotermal. O LnBDC e o CB[6] estão localizados dentro dos poros do carvão, como foi observado em análise MEV-EDS, Raio X de pó e IV. A análise de porosimetria mostrou valores tipicamente entre o material CA e LnBDC, com tamanho de poro e área de superfície, respectivamente, 29,56 Å e 353,98 m²g⁻¹ para LnBDC@CA e 35,53 Å e 353,98 m²g⁻¹ para CB[6]@CA. Ambos os materiais mostraram boa capacidade de adsorção para o alaranjado de metila (MO) e o azul de metileno (MB) com seletividade em função do pH. Em meio ácido, ambos os materiais apresentam seletividade por MB e em pH alcalino para o MO, com desempenho perceptível para o CB[6]@CA. Adicionalmente, a luminescência do európio foi utilizada como sonda estrutural para investigar o ambiente de coordenação do íon Eu³⁺ no compósito EuBDC@CA após experimentos de adsorção. / This work presents the synthesis Already known of MOF [Zn2(BDC)2(dpNDI)] (BDC = 1,4-benzenedicarboxylate, dpNDI = N'N'-di (4-pyridyl) -1,4,5,8 - naphthalenediimide), but now doped in different percentages (0.1%, 0.5%, 1%, 2% and 5%) with the europium ion (probe ion) by Solvothermal synthesis. After their characterizations, spectroscopic responses are observed, in touch to monoaromatic, favorable in the identification of guest molecules. The synthesis and characterization of crystalline coordination networks, as well as activated carbon based composites, from lanthanide ions (Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Dy³⁺, Er³⁺, Tm³⁺ e o Yb³⁺) with the use of flexible ligands, succinate, using the hydrothermal technique to obtain these systems, were performed, in addition to investigations of mixmetal systems in this same carbonaceous matrix. New porous composites LnBDC@AC (AC= Activated carbon, Ln= Pr3+; Nd³⁺; Sm³⁺; Eu³⁺; Gd³⁺; Er³⁺; Tm³⁺ e Yb³⁺ and BDC= 1,4benzenedicaboxylate) and CB[6]@AC (CB[6]= Cucurbit[6]uril) were obtained using hydrothermal route. The LnBDC and CB[B] are located inside the pore of the carbon materials as was observed in SEM-EDS, XRPD and FT-IR analysis. Porosimetry analysis showed values typically between AC and LnBDC material, with pore size and surface area, respectively, 29,56 Å and 353.98 m2g-1 for LnBDC@AC and 35,53 Å and 353.98 m²g⁻¹ for CB[6]@AC. Both materials showed good absorptive capacity of metil orange (MO) and methylene blue (MB) with selectivity as a function of pH. In acid medium, both materials present selectivity by MB and alkaline pH for MO, with notable performance for CB[6]@AC. Additionally, europium luminescence was used as structural probe to investigate the coordination environment of Eu³⁺ ions in the EuBDC@AC composite after adsorption experiment.

Les structures organométalliques poreuses (Metal Organic Framework, MOF) sont une nouvelle classe de matériaux, composées d'ions métalliques ou de clusters liés à des ligands organiques ou des complexes organométalliques dans des réseaux cristallins 1D, 2D ou 3D. Au cours de cette thèse la possibilité de construire de nouveaux MOF a été illustrée par le développement de matériaux MOF à base d’imidazolium, précurseur important pour la synthèse de catalyseurs. En outre, ce travail démontre l’utilité de la modification post-synthèse des MOFs par chimie organométallique de surface à visée catalytique : i) un MOF connu, UiO-66, avec des pores relativement petits a été fonctionnalisé avec un groupement amino et ses capacités d'adsorption de gaz ont été étudiées. ii) la synthèse de MOF a structure poreuse, CPO-27, MOF a été optimisée et utilisée comme précurseur pour produire un catalyseur d'hydrodésulfuration après l'introduction d'espèces actives, via la chimie organométallique de surface, dont les performances catalytiques ont été évaluées / Metal organic frameworks (MOF) are a new class of material, which consist of metal ions or clusters coordinated to organic ligands or metal-organic complexes and result in 1D, 2D or 3D crystalline networks. The possibility of constructing new MOF has been exemplified in this thesis by development of imidazolium based MOF, a highly important ligand system in catalysis. Moreover, this work has performed post synthesis modification via surface organometallic chemistry on existing MOF: i) a known MOF, UiO-66, with relatively small pores has been functionalized with amino group and its gas adsorption capacity has been investigated, ii) the syntheses of a 3D open structure MOF, CPO-27, MOFs have been optimized and used as a precursor to produce a hydrodesulfurization catalyst after introducing active species via surface organometallic chemistry approach, whose catalytic performances have been measured

Les structures organométalliques poreuses (Metal Organic Framework, MOF) sont une nouvelle classe de matériaux, composées d'ions métalliques ou de clusters liés à des ligands organiques ou des complexes organométalliques dans des réseaux cristallins 1D, 2D ou 3D. Au cours de cette thèse la possibilité de construire de nouveaux MOF a été illustrée par le développement de matériaux MOF à base d'imidazolium, précurseur important pour la synthèse de catalyseurs. En outre, ce travail démontre l'utilité de la modification post-synthèse des MOFs par chimie organométallique de surface à visée catalytique : i) un MOF connu, UiO-66, avec des pores relativement petits a été fonctionnalisé avec un groupement amino et ses capacités d'adsorption de gaz ont été étudiées. ii) la synthèse de MOF a structure poreuse, CPO-27, MOF a été optimisée et utilisée comme précurseur pour produire un catalyseur d'hydrodésulfuration après l'introduction d'espèces actives, via la chimie organométallique de surface, dont les performances catalytiques ont été évaluées.

Two of the hottest areas in porous materials research in the last decade have been in energy storage, mainly hydrogen and methane, and in carbon capture and sequestration (CCS). Although these topics are intricately linked in terms of our future energy landscape, the specific materials needed to solve these problems must have significantly different properties. High pressure gas storage is most often linked with high surface areas and pore volumes, while carbon capture sorbents require high sorption enthalpies to achieve the needed selectivity. The latter typically involves separating CO2 from mixed gas streams of mostly nitrogen via a temperature swing adsorption (TSA) process. Much of the excitement has arisen because of the potential of metal-organic frameworks (MOFs) and porous polymer networks (PPNs). Both classes of materials have extremely high surface areas (upwards of 4000 m2/g) and can be modified to have specific physical properties, thus enabling high performance materials for targeted applications. This dissertation focuses on the synthesis and characterization of these novel materials for both applications by tuning framework topologies, composition, and surface properties. Specifically, two routes to synthesize a single molecule trap (SMT) highlight the flexibility of MOF design and ability to tune a framework to interact with specifically one guest molecule; computational and experimental evidence of the binding mechanism are shown as well. Furthermore, eight PPNs are synthesized and characterized for post-combustion carbon capture and direct air capture applications. In addition a high-throughput model, grounded in thermodynamics, to calculate the energy penalty associated with the carbon capture step is presented in order to evaluate all materials for TSA applications provide a comparison to the state of the art capture technologies. This includes results of working capacity and energy calculations to determine parasitic loads (per ton of CO2 captured) from readily available experimental data of any material (adsorption isotherms and heat capacities) using a few simple equations. Through various systematic investigations, trends are analyzed to form structure property relationships that will aid future material development.

Solar energy is a sustainable resource which has substantial potential to meet the increasing demand for renewable energy. Though there has been some success in harvesting solar energy for electricity production, converting solar energy to chemical energy as fuels is still a challenge due to low efficiency. Since the discovery of TiO2 photocatalysts for splitting water (4) and reducing CO2 (5) to form useful chemical feedstock such as H2, CO and CH4, much research has been done to increase the efficiency of photocatalysts. However, the current conversion efficiency of photocatalysts remains low (~5%) (6, 7). Issues being addressed include the wide bandgap and mismatched band edge for reactions (thermodynamic energy for reaction), poor quantum efficiency of the photon collector systems, high recombination of e-/h+ pairs and limitation in the rate of charge transfer from photocatalyst to reactants. This work focuses on improving efficiency of photocatalysts for fuel production through several approaches: (1) engineering a metal-organic-framework (MOF) to have proper band gaps and band edges for targeted reactions and for enhancing photoadsorption in the visible light range, (2) tuning an ABO3-type perovskite for desired bandgaps and thermodynamically favored bandedges for CO2 reduction with water in visible light range. A porphyrin-based Ti-MOF is studied for CO2 photoreduction to gaseous chemical fuels such as CH4 and CO. The porphyrin linkers allow porphyrin-based MOF-525 to achieve narrow bandgap (Eg = ~1.7eV) to absorb visible light, indicating its ability to harvest more solar energy than conventional TiO2. Ti/Zr-MOF-525 also exhibited the appropriate energy level alignment for CO2 and H2O redox reaction for CO and CH4 production. Its CO2 photoreactivity under visible light was demonstrated in a photoreaction, illuminated by 150W Xenon solar simulator. Interestingly, Ti/Zr-MOF-525 demonstrates a selectivity toward CH4, a more valuable fuels than CO. The gas phase reaction condition is an advance over liquid photoreaction. The catalyst stability was also studied and presented. After 3 cycles of reactions, Ti/Zr-MOF-525 is relatively stable for CO2 photoreduction and able to maintain its photoreactivity at about 60-65% of fresh catalyst. The reduction of reactivity is due to a less stable fresh catalyst. When investigating LaCr1-xFexO3 perovskite oxides for photocatalyst, it was found that when replacing Cr ions at the B sites of LaCrO3 by Fe ions, the bandgap does not follow a linear trend in regards to metal ratio composition but rather reflects the smaller bandgap of LaFeO3. Bandedges were successfully measured for the new synthesized materials. At x = 0.25, the conduction band potential remains similar with x = 0. However, at x = 0.75, the conduction band potential was more negative than either perovskites at x = 0 or x = 1. Future simulation of density of state could address this interesting observation. CO2 reduction relativities of each perovskites were predicted well by their measured bandgaps and bandedges. Among five studied perovskites, synthesized LaCr0.25Fe0.75O3 (x = 0.75) is the most active for CO2 photoreduction under visible illumination at room temperature thanks to its small bandgap (2.0 eV) and its suitable bandedges for CO2 photoreduction.

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

Submitted by ANA KARLA PEREIRA RODRIGUES (anakarla_@hotmail.com) on 2017-08-01T12:29:24Z No. of bitstreams: 1 arquivototal.pdf: 4942842 bytes, checksum: f0ad011fa73c8b3eb2a49c98e8ca9de4 (MD5) / Made available in DSpace on 2017-08-01T12:29:24Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4942842 bytes, checksum: f0ad011fa73c8b3eb2a49c98e8ca9de4 (MD5) Previous issue date: 2017-02-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Currently several works have been developed in order to provide alternative routes for the synthesis of several organic compounds. These new protocols are generally aimed at obtaining softer and more eco-friendly reactive conditions, better yields and / or reactional times, and mechanistic studies, among others. This work consists of the study of synthesis routes of cyanohydrins and tetrahydropyrans, using lanthanide catalysts and ionic liquids, respectively. As cyanohydrins are products that can be transformed into important organic intermediates. They are obtained by the cyanosilylation of aldehydes reaction, which is synthetically viable only in the presence of a Lewis acid. In this work, the MOF [Eu2 (MELL)(H2O)6] was used as a heterogeneous catalyst in the cyanosilylation of aldehydes reaction. The catalytic assays were optimized using a thermally activated MOF in acetonitrile. Different aldehydes several structurally provided their respective cyanohydrins ranging from 1 to 6 hours and yields of 62 to 100%. The MOF was recycled in the addition reaction of TMSCN to 2-furfuraldehyde without loss of activity for five cycles. Tetrahydropyran rings (THP) are common in many natural products, so various strategies are being developed to synthesize them. In this work we also describe the study to obtain 2,4,6-trisubstituted tetrahydropyrans in a single step promoted by the ionic liquid (IL) BMIM][PF6] between the allyl bromide and aldehydes, through the Barbier-Prins reaction. The tests were performed under different conditions and optimized using 1: 4 benzaldehyde and allyl bromide. The use of IL [BMIM][PF6] provided THPs of various aldehydes in good yields ranging from 40% to 75% in 8 hours of reaction. In addition, IL [BMIM][PF6] was recovered and reused in the preparation of 4-bromo-2,6-diphenyl-tetrahydro-2H-pyran by up to 5 times without significant loss of yield of that product. The influence of the PF6- anion on the reaction between benzaldehyde and allyl bromide under the Barbier reaction conditions was investigated, as well as the influence of SnBr2 salt on the Prins cyclization reaction between homoallylic alcohol and benzaldehyde. The results show evidence that PF6- acts by accelerating the Barbier reaction and the excess of SnBr2 acts as Lewis acid in the Prins cyclization reaction. Subsequently, the use of KI in the reaction between benzaldehyde and allyl bromide was investigated, and it was found that depending on the ratio used between KI and SnBr2, the preferential formation of homoalyl alcohol or THP compound could occur. / Atualmente vários trabalhos têm sido desenvolvidos no intuito de possibilitar rotas alternativas para a síntese de diversos compostos orgânicos. Esses novos protocolos visam geralmente a obtenção de condições reacionais mais brandas e eco-amigáveis, melhores rendimentos e/ou tempos reacionais, estudos mecanísticos entre outros. Este trabalho consiste no estudo de rotas de síntese de cianoidrinas e tetraidropiranos, utilizando catalisadores de lantanídeos e líquidos iônicos, respectivamente. As cianoidrinas são substâncias que podem ser transformadas em intermediários orgânicos importantes. São geralmente obtidas através da reação de cianossililação de aldeídos, que é sinteticamente viável apenas na presença de um ácido de Lewis. Nesse trabalho, a MOF [Eu2(MELL)(H2O)6] foi utilizada como catalisador heterogêneo na reação de cianossililação de aldeídos. Os ensaios catalíticos foram otimizados utilizando a MOF ativada termicamente em acetonitrila. Diversos aldeídos estruturalmente diferentes forneceram suas respectivas cianoidrinas variando de 1 a 6 horas e com rendimentos de 62 a 100%. A MOF foi reciclada na reação de adição de TMSCN à 2-furfuraldeído sem perda de atividade durante cinco ciclos. Anéis tetraidropirânicos (THP) são comuns em vários produtos naturais, portanto várias estratégias estão sendo desenvolvidas para sintetizá-los. Nesse trabalho descrevemos também o estudo para a obtenção de tetraidropiranos 2,4,6-trissubstituídos meso em uma única etapa promovida pelo líquido iônico (LI) BMIM][PF6] entre o brometo de alila e aldeídos, através da reação Barbier-Prins. Os testes foram realizados sob diferentes condições e foi otimizado utilizando-se o benzaldeído e brometo de alila na proporção 1:4. A utilização LI [BMIM][PF6] forneceu produtos THPs de vários aldeídos com bons rendimentos variando-se de 40% a 75% em 8 horas de reação. Adicionalmente o LI [BMIM][PF6] foi recuperado e reutilizado na preparação do 4-bromo-2,6-difenil-tetraidro-2H-pirano em até 5 vezes sem perda significativa dos rendimentos desse produto. Foi investigado a influência isolada do ânion PF6- na reação entre o benzaldeído e o brometo de alila nas condições reacionais de Barbier, assim como a influência do sal SnBr2 na reação de ciclização de Prins entre o álcool homoalílico e o benzaldeído. Os resultados mostram evidências que o PF6- atua acelerando a reação de Barbier e o excesso de SnBr2 atua como ácido de Lewis na reação de ciclização de Prins. Posteriormente foi investigado a utilização do KI na reação entre o benzaldeído e o brometo de alila, e verificou-se que dependendo da proporção utilizada entre o KI e o SnBr2 pode ocorrer a formação preferencial do álcool homoalílico ou do composto THP.Atualmente vários trabalhos têm sido desenvolvidos no intuito de possibilitar rotas alternativas para a síntese de diversos compostos orgânicos. Esses novos protocolos visam geralmente a obtenção de condições reacionais mais brandas e eco-amigáveis, melhores rendimentos e/ou tempos reacionais, estudos mecanísticos entre outros. Este trabalho consiste no estudo de rotas de síntese de cianoidrinas e tetraidropiranos, utilizando catalisadores de lantanídeos e líquidos iônicos, respectivamente. As cianoidrinas são substâncias que podem ser transformadas em intermediários orgânicos importantes. São geralmente obtidas através da reação de cianossililação de aldeídos, que é sinteticamente viável apenas na presença de um ácido de Lewis. Nesse trabalho, a MOF [Eu2(MELL)(H2O)6] foi utilizada como catalisador heterogêneo na reação de cianossililação de aldeídos. Os ensaios catalíticos foram otimizados utilizando a MOF ativada termicamente em acetonitrila. Diversos aldeídos estruturalmente diferentes forneceram suas respectivas cianoidrinas variando de 1 a 6 horas e com rendimentos de 62 a 100%. A MOF foi reciclada na reação de adição de TMSCN à 2-furfuraldeído sem perda de atividade durante cinco ciclos. Anéis tetraidropirânicos (THP) são comuns em vários produtos naturais, portanto várias estratégias estão sendo desenvolvidas para sintetizá-los. Nesse trabalho descrevemos também o estudo para a obtenção de tetraidropiranos 2,4,6-trissubstituídos meso em uma única etapa promovida pelo líquido iônico (LI) BMIM][PF6] entre o brometo de alila e aldeídos, através da reação Barbier-Prins. Os testes foram realizados sob diferentes condições e foi otimizado utilizando-se o benzaldeído e brometo de alila na proporção 1:4. A utilização LI [BMIM][PF6] forneceu produtos THPs de vários aldeídos com bons rendimentos variando-se de 40% a 75% em 8 horas de reação. Adicionalmente o LI [BMIM][PF6] foi recuperado e reutilizado na preparação do 4-bromo-2,6-difenil-tetraidro-2H-pirano em até 5 vezes sem perda significativa dos rendimentos desse produto. Foi investigado a influência isolada do ânion PF6- na reação entre o benzaldeído e o brometo de alila nas condições reacionais de Barbier, assim como a influência do sal SnBr2 na reação de ciclização de Prins entre o álcool homoalílico e o benzaldeído. Os resultados mostram evidências que o PF6- atua acelerando a reação de Barbier e o excesso de SnBr2 atua como ácido de Lewis na reação de ciclização de Prins. Posteriormente foi investigado a utilização do KI na reação entre o benzaldeído e o brometo de alila, e verificou-se que dependendo da proporção utilizada entre o KI e o SnBr2 pode ocorrer a formação preferencial do álcool homoalílico ou do composto THP.

Les MOFs sont des solides à la structure cristalline poreuse à base de clusters métalliques et de ligands organiques qui font l'objet de très nombreuses études, dans des champs d'applications très variés, qui vont de la catalyse au « drug delivery », en passant par le stockage de gaz et, plus récemment, en tant que senseurs biologiques. Les ligands organiques, qui les constituent, peuvent lorsqu'ils possèdent un point d'ancrage, comme des groupements amino, être fonctionnalisés grâce à des réactions chimiques. Les travaux présentés dans cette thèse reportent la fonctionnalisation de MOFs, via différentes stratégies, comme des greffages covalent et issues de la chimie de coordination, tel que le couplage peptidique ou encore la synthèse d'urée. Dans cette thèse, est notamment présentée une nouvelle méthode permettant de greffer très rapidement des peptides chiraux dans les nanopores des MOFs. Une large bibliothèque MOF-peptides a ainsi été obtenue et caractérisée. Ces nouveaux composés ont également été utilisés pour l'ancrage de complexes organométalliques dans les cavités des MOFs. Suivant un échange de ligands post-synthétique, il a aussi été possible d'intégrer un complexe organométallique photo-catalytique dans la structure d'un MOF, améliorant ainsi ses activités et sélectivités pour la photo-réduction de CO2. Enfin, les performances catalytiques de ces derniers matériaux MOFs se sont révélées supérieures aux versions homogènes des complexes, ce qui offre de nouvelles opportunités pour la catalyse fine / Metal Organic Frameworks, MOFs, are porous crystalline solid based on metal clusters and organic ligands, investigated for numerous applications such as catalysis, drug delivery, gas storage and, more recently, biosensors. The work presented in this thesis focuses on functionalizing MOFs through different strategies, such as covalent grafting or surface coordination chemistry, through chemical reactions, such as peptide coupling or synthesis of urea. In particular, a new method to very quickly graft chiral peptides into the nanopores of MOFs is reported. A large library of MOF-peptides has thus been obtained and characterized. These novel compounds have also been used for grafting organometallics in the cavities of MOFs. Following a post-synthetic ligand exchange, it was also possible to integrate a photocatalytic complex in the structure of a MOF, improving its activities and selectivities for the photocatalytic CO2 reduction. In general, the catalytic performances of these materials were superior to those of their homogeneous counterparts, thus further expanding the potential of MOFs as well-defined heterogeneous catalysts for fine chemistry

Metal Organic Framework (MOF) materials, consisting of metal ions with organic linkers, have a functional cavity structure which can be utilized in applications such as catalyst, micro sensing, and gas absorption. Due to MOF materials' selective gas adsorption property, interest in MOF materials has intensified in the last few years, particularly for CO, CO₂, N₂, CH₄, and H₂. MOF materials are typically synthesized by reaction under hydrothermal conditions which yields a highly crystalline product. However, reaction under solvothermal condition typically requires long reaction times - from 8 hours up to several days depending upon the particular MOF material and the reaction conditions, such as solvent, temperature, and concentration. Other synthesis methods that have been developed to address these issues include microwave synthesis, sonochemical synthesis, and mechanochemical synthesis. Reaction time can be reduced to minutes under the high energy conditions of a microwave synthesis method. A solvent free synthesis can be achieved using the mechanochemical synthesis. The sonochemical synthesis method provides an environmentally friendly process. However, all of these synthesis methods above are batch processes and meet several difficulties in scalability and controllability. Herein, we introduce a new synthesis method for MOF materials which utilizes a continuous flow reactor process. To reduce the reaction time and solvent usage, and to maintain a high degree of the crystallinity are the goals of this study. Cu-BTC (BTC = Benzene, -1,3,5-Tricarboxylate ) or HKUST-1 Metal Organic Framework material was chosen to demonstrate the continuous flow reactor process since it has a simple MOF structure, consisting of Cu⁺² ions and BTC linkers, and has been widely studied for catalyst applications. The continuous flow synthesis method shows successful results of reduced residence time as low as 5 minutes, high crystal quality obtained, size control, and high yield with recycle solvent cooperation. The particle size control of MOF material has been shown crucial contributions in absorption application and is accomplished by adjusting the system temperature, flow rate, and solvent composition ratio. A water/ethanol mixture as the solvent in Cu-BTC synthesis reaction is environmentally friendly and easy to separate from the MOF product. In addition, the composition of water in solvent is the most influential factor to the crystal growth rate specifically in crystallization rate and nucleation rate. BTC is used in excess to achieve a production yield of about 97% based on Cu ion consumption. Since the Cu-BTC particles have a low solubility in the ethanol/water solution, they can be obtained easily using a dispersion/sonication method. The BTC rich supernatant can be recycled for use in the feed stream to maintain a high production rate, which can be beneficial for quick economic production in laboratory, as well as, commercial scale applications. / Graduation date: 2012

The aim of this thesis was to examine the ability of metal organic frameworks (MOFs) to store and controllably release biologically significant amounts of nitric oxide (NO). Initial work involved the synthesis of a series of isostructural MOFs, known as M-CPO-27, which display coordinatively unsaturated metal sites (CUSs) when fully activated (guest solvent molecules both coordinated and uncoordinated to the metal atom are removed). Two of these frameworks (Ni and Co CPO-27) displayed exceptional performance over the entire cycle of activation, storage and delivery showing the largest storage and release of NO of any known porous material (up to 7 mmolg⁻¹). These frameworks would therefore be considered for initial research into the formulation of MOFs, for possible use in medical applications. It was shown that they still release large amounts of NO even when placed inside porous paper bags, creams or hydrocolloids. The other versions of M-CPO-27 also displayed significant adsorption of NO however they show poor total NO release. It was also shown that it is possible to synthesise both Ni and Co CPO-27 using microwave synthesis without any detrimental effect to the porous structure. Several iron-based MOFs were also investigated for NO storage and release. The results showed that Fe MIL-88 based structures adsorb good amounts of NO but only release a small amount of the irreversibly adsorbed NO. Two successfully amine grafted giant pore MOFs were then investigated to attempt to improve the NO adsorption and release. This result was not observed however, due to the poor total amine grafting coverage and pore blockage resulting from the amines. In-situ IR studies reveal that when exposed to NO, activated Fe MIL-100 forms a chemical bond with the NO. The studies also displayed that when water is then allowed to attempt to replace the NO that only a small amount of NO is actually released, the majority of the NO either remains chemically bonded to the Fe atom or forms N₂O in conjunction with a Fe-OH group. Other MOFs were also successfully synthesised and characterised for NO storage and release. Both Ni succinate and Ni STA-12 display good adsorption and excellent release of NO. This indicates that Ni based MOFs show the best results for NO adsorption and release. In the conclusion of the thesis I am able to categorise the NO release ability of MOFs based on composition and formulate a theory as to why this happens.