abstract: Metal Organic Frameworks(MOFs) have been used in various applications, including sensors. The unique crystalline structure of MOFs in addition to controllability of their pore size and their intake selectivity makes them a promising method of detection. Detection of metal ions in water using a binary mixture of luminescent MOFs has been reported. 3 MOFs(ZrPDA, UiO-66 and UiO-66-NH2) as detectors and 4 metal ions(Pb2+, Ni2+, Ba2+ and Cu2+) as the target species were chosen based on cost, water stability, application and end goals. It is possible to detect metal ions such as Pb2+ at concentrations at low as 0.005 molar using MOFs. Also, based on the luminescence responses, a method of distinguishing between similar metal ions has been proposed. It is shown that using a mixture of MOFs with dierent reaction to metal ions can lead to unique and specic 3D luminescence maps, which can be used to identify the present metal ions in water and their amount. In addition to the response of a single MOF to addition of a single metal ion, luminescence response of ZrPDA + UiO-66 mixture to increasing concentration of each of 4 metal ions was studied, and summarized. A new peak is observed in the mixture, that did not exist before, and it is proposed that this peak requires metal ions to activate / Dissertation/Thesis / Masters Thesis Materials Science and Engineering 2018

Submitted by Guilherme Arroyos null (guiarroyos@gmail.com) on 2018-03-20T14:13:03Z No. of bitstreams: 1 DISSERTAÇÃO DE MESTRADO GUILHERME ARROYOS.pdf: 8526991 bytes, checksum: f3c3ac9d633deb1a24a357f7c55b9819 (MD5) / Rejected by Ana Carolina Gonçalves Bet null (abet@iq.unesp.br), reason: Prezado Guilherme Arroyos, Solicitamos que realize a correção na submissão seguindo a orientação abaixo: Inclusão da Ficha Catalográfica no trabalho. Agradecemos a compreensão. on 2018-03-23T14:03:32Z (GMT) / Submitted by Guilherme Arroyos null (guiarroyos@gmail.com) on 2018-03-23T14:10:47Z No. of bitstreams: 1 DISSERTAÇÃO DE MESTRADO FINAL.pdf: 8591215 bytes, checksum: 599b8b89fcdc4e3ee1ee1be2261729c1 (MD5) / Approved for entry into archive by Ana Carolina Gonçalves Bet null (abet@iq.unesp.br) on 2018-03-23T17:23:06Z (GMT) No. of bitstreams: 1 arroyos_g_me_araiq_int.pdf: 8520705 bytes, checksum: 750f8f7bf0f7ffed7bba14f02afd5cf0 (MD5) / Made available in DSpace on 2018-03-23T17:23:06Z (GMT). No. of bitstreams: 1 arroyos_g_me_araiq_int.pdf: 8520705 bytes, checksum: 750f8f7bf0f7ffed7bba14f02afd5cf0 (MD5) Previous issue date: 2018-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Segundo a IUPAC, MOFs (Metal-Organic Frameworks) são definidos como polímeros de coordenação com uma estrutura aberta contendo cavidades potencialmente vazias. As MOFs podem ser sintetizadas utilizando íons lantanídeos como centros metálicos (LnMOFs) e por essa razão, apresentam luminescência somada às demais propriedades desta classe de materiais porosos. Dentro desse contexto, o objetivo deste trabalho foi a obtenção de LnMOFs visando aplicação na área de sensoriamento químico via luminescência. Os compostos foram sintetizados a partir dos cloretos de térbio (III), európio (III) e samário (III) hexahidratados (precursores metálicos) e dos ligantes ácidos malônico e 3,5-pirazoldicarboxílico. Os compostos de térbio e ligantes foram sintetizados em diferentes pHs, sendo que os valores iguais a 2, 4 e 5 conduziram a formação dos materiais TBM2, TBM4 e TBM5, respectivamente. Os sólidos de európio e samário foram sintetizados em pH igual a 5 (compostos EUM5 e SMM5, respectivamente). As sínteses foram realizadas utilizando micro-ondas e estufa solvotérmica. As amostras TBM4 e TBM5 obtidas via micro-ondas se organizam na forma de partículas com tamanhos entre 0,5 - 2 μm e morfologia esférica. Ensaios de caracterização demonstraram que se tratava do mesmo composto, exceto uma maior rugosidade nas partículas do TBM5. A cristalinidade do material foi baixa devido ao curto tempo de síntese, no entanto utilizando síntese solvotérmica (mais lenta) foi possível aumentar a cristalinidade. Há bandas características de ambos os ligantes na espectroscopia vibracional no infravermelho, assim como os deslocamentos de bandas ocasionados pela coordenação ao íon metálico. O composto apresentou boa estabilidade térmica, iniciando sua decomposição na temperatura de 455 °C. O material também apresentou intensa emissão de luz verde quando exposto à radiação ultravioleta. Esta propriedade de luminescência foi utilizada para os testes de sensoriamento de gás carbônico e íons cobre (II), apresentando variações na intensidade de emissão após exposição aos analitos. Após exposição ao CO2, a intensidade de luminescência aumentou, enquanto que após exposição ao Cu2+ a intensidade diminuiu, conforme a concentração. O composto EUM5 apresentou baixa intensidade de luminescência e o SMM5 não apresentou emissão de luz. O composto TBM2 via síntese solvotérmica foi obtido na forma de monocristais luminescentes. A técnica de difração de raios-X de monocristal elucidou a estrutura do material, onde foi possível observar que o ligante ácido malônico não coordenou neste caso. Foi investigada ainda nesse trabalho a influência da rota sintética e de alguns parâmetros experimentais (concentração dos reagentes, uso de modulador de coordenação) no tipo de produto formado. / According to IUPAC, MOFs (Metal-Organic Frameworks) are coordination polymers with an open structure containing potentially empty voids. MOFs can be synthesized using lanthanide ions as metal centers (LnMOFs) and therefore have luminescence added to the other properties of this porous materials class. In this context, the objective of this work was to obtain LnMOFs for chemical sensing application via luminescence. The compounds were synthesized from terbium (III), europium (III) and samarium (III) chlorides hexahydrates (metal precursors) and the malonic and 3,5-pyrazoledicarboxylic acid linkers. The compounds with terbium plus linkers were synthesized at different pHs, with values of 2, 4 and 5 leading to the formation of TBM2, TBM4 and TBM5 materials, respectively. The europium and samarium solids were synthesized at pH = 5 (compounds EUM5 and SMM5, respectively). The syntheses were microwave and solvothermic assisted. The TBM4 and TBM5 samples via microwave-assisted synthesis are organized in the form of particles with sizes between 0.5 - 2 μm and spherical morphology. Characterization tests showed both are the same compound, except for a greater roughness in the TBM5 particles. The crystallinity of the material was low due to the short synthesis time; however, by using solvothermic-assisted synthesis (slower) it was possible to increase the crystallinity. There are characteristic bands of both ligands in the infrared vibrational spectroscopy, as well as band displacements caused by coordination to the metal ion. The compound presented good thermal stability, initiating its decomposition at the temperature of 455.7 °C. The material also showed intense green light emission when exposed to ultraviolet radiation. This luminescence property was investigated for the carbon dioxide and copper (II) sensing tests, showing variations in emission intensity after exposure to analytes. After exposure to CO2, the intensity of luminescence increased, while after exposure to Cu2+ the intensity decreased, depending on the concentration. The compound EUM5 showed low luminescence intensity and SMM5 did not show emission. The TBM2 compound obtained via solvothermic synthesis organized itself in the form of luminescent single crystals. The single crystal X-ray diffraction technique elucidated the structure of the material, where it was possible to observe that the malonic acid binder did not coordinate in this case. The influence of the synthetic route and some experimental parameters (reagent concentration, use of coordination modulator) on the type of product were also investigated.

Made available in DSpace on 2014-06-12T15:51:42Z (GMT). No. of bitstreams: 2 arquivo5730_1.pdf: 3538315 bytes, checksum: 46fed7163ef22bb65241ae2095c91e39 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Recentemente uma nova classe de materiais nano- e meso-porosos foi desenvolvida baseada em redes metal-orgânicas (MOFs), que, por manterem sua porosidade e estrutura cristalina, tem provocado mudanças significativas no campo de armazenamento e separação de gáses, catálise e química em espaços confinados. O desenvolvimento de novos materiais é indispensável para eliminar alguns problemas no armazenamento de gás natural, tais como alta pressão (acima de 182 atm), o que acarreta altos custos e risco. A adsorção e dessorção do gás natural em materiais porosos sólidos podem resolver esse problema. Devido à grande área superficial, porosidade e versatilidade (facilidade para realizar modificações nos espaçadores orgânicos), MOFs e suas classes isoreticulares (IRMOFs) são materiais de grande potencial para fins de armazenamento de gás. De fato, IRMOFs têm a mesma estrutura reticular, mas podem ter uma grande variedade de grupos funcionais, podendo então ser utilizadas do desenvolvimento racional de materiais sorventes para aplicações específicas. As IRMOFs possuem a unidade de construção OZn4(OOC)6 em cada vértice do cubo, que são conectados por espaçadores orgânicos dicarboxilatos. Realizamos simulações computacionais de Monte Carlo Grã-Canônico (GCMC) para obter as isotermas de adsorção absolutas do metano para diversas IRMOFs. As estruturas das IRMOFs foram obtidas com o método quântico semi-empírico AM1 e foram mantidas rígidas durante as simulações GCMC, sendo as moléculas de metano modeladas como esferas rígidas e interagindo entre si e com a IRMOF por um potencial de Lennard-Jones. Os parâmetros deste potencial de interação intermolecular foram obtidos do campo de força universal (UFF) e condições periódicas foram empregadas. Uma nova metodologia foi proposta para determinar a quantidade adsorvida de excesso e efetiva, e assim viabilizar a comparação com os resultados experimentais. Elas consistem em simulações das isotermas de adsorção do gás hélio e do metano sem interações com a IRMOF nas mesmas condições termodinâmicas. Dentre as quinze IRMOFs estudadas, a que teve maior quantidade adsorvida de metano, 240 cm3(CNTP)/cm3, foi a IRMOF-993-4S que consiste de um anel antraceno modificado com átomos de enxofre. As metodologias para determinar as quantidades adsorvidas de excesso e efetiva são simples, sistemáticas e propensas a cancelamento de erros. Entretanto, requerem o dobro de simulações, mas dada a rapidez das simulações esta não é uma limitação muito severa e as metodologias parecem ser adequadas para fornecer, pelo menos, tendências semiquantitativas e servir como ferramenta para a seleção rápida de potenciais adsorventes de gases

A significant and ongoing challenge in materials chemistry and furthermore solid state chemistry is to design materials with the desired properties and characteristics. The field of Metal-Organic Frameworks (MOFs) offers several strategies to address this challenge and has proven fruitful at allowing some degree of control over the resultant materials synthesized. Several methodologies for synthesis of MOFs have been developed which rely on use of predetermined building blocks. The work presented herein is focused on the utilization of two of these design principles, namely the use of molecular building blocks (MBBs) and supermolecular building blocks (SBBs) to target MOF materials having desired connectivities (topologies). These design strategies also permit the introduction of specific chemical moieties, allowing for modification of the MOFs properties. This research is predominantly focused on two platforms (rht-MOFs and ftw-MOFs) which topologically speaking are edge transitive binodal nets; ftw being a (4,12)-connected net and rht being a (3,24)-connected net. These highly connected nets (at least one node having connectivity greater than eight) have been purposefully targeted to increase the predictability of structural outcome. A general trend in topology is that there is an inverse relationship between the connectivity of the node(s) and the number of topological outcomes. Therefore the key to this research (and to effective use of the SBB and MBB approaches) is identification of conditions which allow for reliable formation of the targeted MBBs and SBBs. In the case of the research presented herein: a 12-connected Group IV or Rare Earth based hexanuclear MBB and a 24-connected transition metal based SBB were successfully targeted and synthesized. These two synthetic platforms will be presented and used as examples of how these design methods have been (and can be further) utilized to modify existing materials or develop new materials for gas storage and separation applications for environmental and energy related applications including hydrogen, methane, carbon dioxide and hydrocarbon storage or separations.

Metal-Organic Frameworks (MOFs) represent an emerging new class of functional crystalline solid-state materials. In the early discovery of this now rapidly growing class of materials significant challenges were often encountered. However, MOFs today, with its vast structural modularity, reflected by the huge library of the available chemical building blocks, and exceptional controlled porosity, stand as the most promising candidate to address many of the overbearing societal challenges pertaining to energy and environmental sustainability. A variety of design strategies have been enumerated in the literature which rely on the use of predesigned building blocks paving the way towards potentially more predictable structures. The two major design strategies presented in this work are the molecular building block (MBB) and supermolecular building block (SBB) -based approaches for the rationale assembly of functional MOF materials with the desired structural features. In this context, we targeted two highly connected MOF platforms, namely rht-MOF and shp-MOF. These two MOF platforms are classified based on their topology, defined as the underlying connectivity of their respective net, as edge transitive binodal nets; shp being (4,12)-connected net and rht being (3,24)-connected net. These highly connected nets were deliberately targeted due to the limited number of possible nets for connecting their associated basic building units. Two highly porous materials were designed and successfully constructed; namely Y-shp-MOF-5 and rht-MOF-10. The Y-shp-MOF-5 features a phenomenal water stability with an exquisite behavior when exposed to water, positioning this microporous material as the best adsorbent for moisture control applications. The shp-MOF platform proved to be modular to ligand functionalization and thus imparting significant behavioral changes when hydrophilic and hydrophobic functionalized ligands were introduced on the resultant MOF. On the other hand, rht-MOF-10 constituting of 24-connected transition metal based-SBB was successfully synthesized and activated using a modified supercritical CO2 drying technique. This allowed access to over 90 % of the total pore volume (1.95cm3/g). High pressure gas sorption measurements of CH4, CO2 and O2 showed that this material has a gravimetric uptake that ranks close to the best materials enlisted for the storage of these corresponding gases.

The object of this thesis is to get a deeper understanding of the role of modulator agents in the synthesis of Zr- and Hf-based metal-organic frameworks (MOFs) and their impact on framework properties, such as textural properties, stability, hydrophobicity, and catalytic activity. For this purpose, MOFs are investigated that are built up by the commercially available linker 2,5-thiophenedicarboxylate and the Zr6(µ3-O)4(µ3-OH)412+ cluster. With proper choice of the modulator a new structure, namely DUT-126 (DUT = Dresden University of Technology), could be presented in the course of this work, besides the already known polymorphs of DUT-67, DUT-68 and DUT-69. Furthermore, DUT-67 is chosen as a model structure to functionalise the metal cluster of the framework by exchanging the modulator post-synthetically with hydrophobic fluorinated monocarboxylic acids. With the introduction of these fluorinated molecules, the surface polarities and the stability against water removal can be tuned. In addition, the metal clusters of DUT-67 were modified with a complete removal of the pristine modulator molecules by means of an acidic treatment in order to generate open metal sites that can function as Lewis acid sites. The suitability of DUT-67 and its acid treated analogues as heterogenous catalyst was tested on the Meerwein-Ponndorf-Verley reduction of cyclohexanone. Furthermore, the UiO-67 analogue DUT-122, which contains the luminescent linker 9-fluorenone-2,7-dicarboxylate, was tested as sensor material to detect solvent vapours. It could be shown that DUT-122 is sensitive to various solvent vapours, which induce photoluminescent shifts and intensity changes of the fluorescence emission profile depending on the polarity and the functionality of the respective solvent.

Many countries around the world have decided to play a positive role in combating climate change and reduce carbon dioxide in the atmosphere. In addition to reducing emissions, initiatives include the capture, storage and utilization of CO2. Converting it to valuable products through reforming of methane not only utilizes major greenhouse gasses, but can also be a means for energy from biogas. The main challenge hindering this process is developing a scalable active catalyst that can resist deactivation. To address this challenge, focus has shifted from simple metal oxides towards metal nanoparticles dispersed and organized in complex well defined structures. Oxide perovskites have the potential to contain metal and support in a single structure as the case of LaNiO3. Metal-organic frameworks are another type of materials that can be used as sacrificial agents to produce the type of complex metal oxides required. Three synthesis approaches were studied for the synthesis of La-Ni materials. Combustion synthesis is a cost and time efficient method. However, it becomes challenging to accurately predict the outcomes. Hydrothermally synthesized perovskites give pure phase materials but are sensitive to synthesis variables. MOF based materials showed conversions of 94% and 83% for CO2 and CH4, respectively, with stable performance for +100 hours and can be a promising future route in heterogeneous catalysis.

Volumetric adsorption experiments were conducted over three sorbates in Zeolitic Imidazolate Framework – 8 (ZIF-8). The sorption isotherms were measured at low temperatures. The study included carbon monoxide sorption in ZIF-8, xenon in ZIF-8, and methane sorption in ZIF-8. As a metal-organic framework that has been investigated thoroughly for its remarkable characteristics, ZIF-8 interactions with the above three sorbates has revealed some new features. Each of these systems offered a unique opportunity to study the physical properties of the sorbate and ZIF-8 and the thermodynamic responses of the system for its unique characteristics. The fundamental understating of sorbents-sorbate not only reveals some of the remarkable properties but also opens up new frontiers for researches in practical applications such as gas storage separation and other sorption-based fields of interest. The investigation into CO-ZIF-8 system has confirmed some of the predictions made on a similar system and analysis on the ZIF-8 structure. The measured adsorption isotherms have confirmed the existence of three pre-saturation subs steps, which were explained in terms of effects from the structural transition and polarity of the sorbate. The behavior of isosteric heat of adsorption and the equilibration time revealed a strong connection between steps in the isotherm and the structural changes of ZIF-8 due to organic linker rotation and volume expansion, also known as “Gate-Opening” in some cases. In both Xe-ZIF-8 and CH4 -ZIF-8 systems, the sorption isotherms revealed two substeps before the saturation. This is the first time such a feature was resolved experimentally in these systems although many previous studies have predicted the feature. The experimental observations on characteristics of the Xe -ZIF-8 system are also verified by computer simulations. Unlike the CO-ZIF-8 system, Xe-ZIF-8 interactions do not trigger the organic linker rotation of ZIF-8 structure, but it influenced the expansion of the ZIF-8 structure. In CH4 – ZIF-8 system the isotherms’ substeps were not as steep as Xe system but the loading dependence of isosteric heat of adsorption and equilibration time revealed features that are similar to CO. The lack of sorption-combined structural analysis of CH4-ZIF-8 prevent us from concluding the actual nature of the changes occurring which are related to the substeps and other thermodynamic and kinetic features. In all three systems, our measurements of the adsorption kinetics, we observed a non-monotonic behavior of the equilibration time as a function of sorbent loading. For CO the loading dependence of equilibration time exhibit peaks at loadings that correspond to the intermediate and higher loading sub-steps, and CH4 showed similar behavior at the loading corresponds to its intermediate substep region. The sharp peaks can be interpreted as packing rearrangement of adsorbed phase molecule in both cases and for CO there may be some contributions from the linker flipping and structural transition. The structural effect of kinetics is yet to be confirmed by a structural analysis for the CH4 system.

Yes / Antimicrobial resistance (AMR) is a growing global crisis with an increasing number of untreatable or exceedingly difficult-to-treat bacterial infections, due to their growing resistance to existing drugs. It is predicted that AMR will be the leading cause of death by 2050. In addition to ongoing efforts on preventive strategies and infection control, there is ongoing research towards the development of novel vaccines, antimicrobial agents, and optimised diagnostic practices to address AMR. However, developing new therapeutic agents and medicines can be a lengthy process. Therefore, there is a parallel ongoing worldwide effort to develop materials for optimised drug delivery to improve efficacy and minimise AMR. Examples of such materials include functionalisation of surfaces so that they can become self-disinfecting or non-fouling, and the development of nanoparticles with promising antimicrobial properties attributed to their ability to damage numerous essential components of pathogens. A relatively new class of materials, metal-organic frameworks (MOFs), is also being investigated for their ability to act as carriers of antimicrobial agents, because of their ultrahigh porosity and modular structures, which can be engineered to control the delivery mechanism of loaded drugs. Biodegradable polymers have also been found to show promising applications as antimicrobial carriers; and, recently, several studies have been reported on delivery of antimicrobial drugs using composites of MOF and biodegradable polymers. This review article reflects on MOFs and polymer-MOF composites, as carriers and delivery agents of antimicrobial drugs, that have been studied recently, and provides an overview of the state of the art in this highly topical area of research.

Yes / Pesticide contamination is a global issue, affecting nearly 44% of the global farming population, and disproportionately affecting farmers and agricultural workers in developing countries. Despite this, global pesticide usage is on the rise, with the growing demand of global food production with increasing population. Different types of porous materials, such as carbon and zeolites, have been explored for the remediation of pesticides from the environment. However, there are some limitations with these materials, especially due to lack of functional groups and relatively modest surface areas. In this regard, metal-organic frameworks (MOFs) provide us with a better alternative to conventionally used porous materials due to their versatile and highly porous structure. Recently, a number of MOFs have been studied for the extraction of pesticides from the environment as well as for targeted and controlled release of agrochemicals. Different types of pesticides and conditions have been investigated, and MOFs have proved their potential in agricultural applications. In this review, the latest studies on delivery and extraction of pesticides using MOFs are systematically reviewed, along with some recent studies on greener ways of pest control through the slow release of chemical compounds from MOF composites. Finally, we present our insights into the key issues concerning the development and translational applications of using MOFs for targeted delivery and pesticide control.