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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Synthesis and Permeation of Large Pore Metal-organic Framework Membranes

January 2015 (has links)
abstract: ABSTRACT Large-pore metal-organic framework (MOF) membranes offer potential in a number of gas and liquid separations due to their wide and selective adsorption capacities. A key characteristic of a number of MOF and zeolitic imidazolate framework (ZIF) membranes is their highly selective adsorption capacities for CO2. These membranes offer very tangible potential to separate CO2 in a wide array of industrially relevant separation processes, such as the separation from CO2 in flue gas emissions, as well as the sweetening of methane. By virtue of this, the purpose of this dissertation is to synthesize and characterize two linear large-pore MOF membranes, MOF-5 and ZIF-68, and to study their gas separation properties in binary mixtures of CO¬2/N2 and CO2/CH4. The three main objectives researched are as follows. The first is to study the pervaporation behavior and stability of MOF-5; this is imperative because although MOF-5 exhibits desirable adsorption and separation characteristics, it is very unstable in atmospheric conditions. In determining its stability and behavior in pervaporation, this material can be utilized in conditions wherein atmospheric levels of moisture can be avoided. The second objective is to synthesize, optimize and characterize a linear, more stable MOF membrane, ZIF-68. The final objective is to study in tandem the high-pressure gas separation behavior of MOF-5 and ZIF-68 in binary gas systems of both CO2/N2 and CO2/CH4. Continuous ZIF-68 membranes were synthesized via the reactive seeding method and the modified reactive seeding method. These membranes, as with the MOF-5 membranes synthesized herein, both showed adherence to Knudsen diffusion, indicating limited defects. Organic solvent experiments indicated that MOF-5 and ZIF-68 were stable in a variety of organic solvents, but both showed reductions in permeation flux of the tested molecules. These reductions were attributed to fouling and found to be cumulative up until a saturation of available bonding sites for molecules was reached and stable pervaporation permeances were reached for both. Gas separation behavior for MOF-5 showed direct dependence on the CO2 partial pressure and the overall feed pressure, while ZIF-68 did not show similar behavior. Differences in separation behavior are attributable to orientation of the ZIF-68 membranes. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2015
112

Síntese e funcionalização de Metal-Organic Frameworks (MOFs) visando aplicação como catalisadores heterogêneos em reações de conversão de CO2 / Synthesis and Functionalization of Metal-Organic Frameworks (MOFs) for application as heterogeneous catalysts in CO2 conversion reactions

Flor, Jader Barbosa da Silva [UNESP] 03 May 2017 (has links)
Submitted by JADER BARBOSA DA SILVA FLOR null (jader@iq.unesp.br) on 2017-05-22T17:08:38Z No. of bitstreams: 1 TESE VERSÃO FINAL para a impressão.pdf: 8986552 bytes, checksum: 9b079a86ffb72f7d5def9d9e6c6ba45e (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-23T17:35:16Z (GMT) No. of bitstreams: 1 flor_jbs_dr_araiq.pdf: 8986552 bytes, checksum: 9b079a86ffb72f7d5def9d9e6c6ba45e (MD5) / Made available in DSpace on 2017-05-23T17:35:16Z (GMT). No. of bitstreams: 1 flor_jbs_dr_araiq.pdf: 8986552 bytes, checksum: 9b079a86ffb72f7d5def9d9e6c6ba45e (MD5) Previous issue date: 2017-05-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste projeto foram sintetizados e caracterizados materiais porosos conhecidos como Metal-Organic Frameworks (MOFs) que abrangem uma área da química que tem experimentado um crescimento muito grande nas duas últimas décadas. MOFs são compostos cristalinos contendo espaços potencialmente vazios (poros) construídos a partir de íons ou clusters metálicos interconectados por espaçadores orgânicos. Além da diversidade estrutural e topológica, estes materiais têm enorme potencial para muitas aplicações. Dentro desse contexto, o objetivo central do trabalho foi a preparação de MOFs de cobre(II) e zinco(II) e investigação da potencialidade de aplicação em catálise heterogênea. Dentre outros materiais, a MOF MOF-INZ foi preparada pela primeira vez a partir da funcionalização da HKUST-1 via processo PSM (Pos-Synthetic Modification) pela coordenação da isoniazida nos centros coordenativamente insaturados (CUSs) do íon cobre(II) do material precursor ativado. A utilização desse material como catalisador em reações de cicloadição de CO2 frente ao epóxido de propileno resultou em 95% de conversão do reagente em carbonato de propileno (após 72 horas, em presença de TBAI). A última etapa do trabalho consistiu na preparação das MOFs ZIF-8 e HKUST-1 em escala nanométrica, usando moduladores de concentração, e no desenvolvimento de uma técnica muito elegante para a formação de filmes finos sobre nanotubos de dióxido de titânio (com diâmetros da ordem de 50-100 nm). Os materiais híbridos preparados foram então submetidos a reações foto- e fotoeletrocatalíticas de redução de CO2. As MOFs adsorvidas nos eletrodos nanoestruturados mostraram atividades significativamente mais altas em comparação com o eletrodo não modificado. Sob irradiação de luz e na presença de ácido ascórbico, o compósito Ti/TiO2-ZIF-8 gerou cerca de 30 mmol/L de etanol e 2 mmol/L de metanol em fase gasosa, enquanto que reações fotoeletrocatalíticas de redução de CO2 produziram 104 mmol/L e 17 mmol/L desses mesmos produtos, respectivamente. Do que seja do nosso conhecimento, essa é a primeira vez que a redução fotoeletrocatalítica desse importante gás causador do efeito estufa é realizada sobre materiais baseado em MOFs e abre uma frente de pesquisa bastante promissora no que tange a introdução dessa importante classe de materiais porosos no design de fotoeletrocatalisadores para reações gasosas. / In this project, porous materials known as Metal-Organic Frameworks (MOFs) were synthesized and characterized, which cover a chemistry area that has experienced a very large growth in the last two decades. MOFs are crystalline compounds containing potentially empty spaces (pores) constructed from ions or metal clusters interconnected by organic spacers. In addition to structural and topological diversity, these materials have enormous potential for many applications. In this context, the main objective of the work was the preparation of copper (II) and zinc (II) MOFs and the investigation of the potentiality of application in heterogeneous catalysis. Among other materials, MOF MOF-INZ was prepared for the first time from the functionalization of HKUST-1 via PSM (Post-Synthetic Modification) process by the coordination of isoniazid to the coordinated unsaturated (CUSs) centers of the copper (II) activated precursor. The use of this material as a catalyst in CO2-cycloaddition reactions to propylene epoxide resulted in 95% conversion of the reactant into propylene carbonate (after 72 hours in the presence of TBAI). The last stage of the work consisted in the preparation of the ZIF-8 and HKUST-1 MOFs at nanoscale using concentration modulators and the development of a very elegant technique for the formation of thin films on titanium dioxide nanotubes (with diameters in the order of 50-100 nm). The prepared hybrid materials were then submitted to photo- and photoelectrocatalytic CO2 reduction reactions. The MOFs adsorbed on the nanostructured electrodes showed significantly higher activities compared to the unmodified electrode. Under light irradiation and in the presence of ascorbic acid, the Ti / TiO2-ZIF-8 composite generated about 30 mmol / L of ethanol and 2 mmol / L of methanol in the gas phase, while photoelectrocatalytic CO2 reduction reactions produced 104 Mmol / L and 17 mmol / L of these same products, respectively. To our knowledge, this is the first time that the photoelectrocatalytic reduction of this important greenhouse gas is carried out on materials based on MOFs and opens a very promising research front regarding the introduction of this important class of porous materials in the design of photoelectrocatalysts for gaseous reactions.
113

Síntese, caracterização e funcionalização superficial de redes metalorgânicas análogas ao MIL-101 / Synthesis, characterization and surface functionalization of metal-organic frameworks analogous to MIL-101

Ferreira, Ricardo Barroso, 1988- 21 August 2018 (has links)
Orientador: André Luiz Barboza Formiga / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-21T22:34:48Z (GMT). No. of bitstreams: 1 Ferreira_RicardoBarroso_M.pdf: 14699923 bytes, checksum: 14c38ecd37cab3267087c49c4b168a4e (MD5) Previous issue date: 2013 / Resumo: O trabalho apresentado explora a modificaçãoo do processo de síntese de uma rede metalorgânica conhecida como MIL-101(Cr), um material formado por clusters trinucleares de crômio(III) unidos por ligantes tereftalato em ponte. A partir do uso de meios reacionais contendo uma mistura de componentes (ligantes ou metais), visou-se a incorporação de diferentes componentes em materiais contendo a mesma estrutura do MIL-101(Cr). Os produtos formados por esta estratégia foram analisados por difração de raios X pelo método de pó, onde se observou que, dependendo da composição do meio reacional, materiais contendo a mesma estrutura do MIL-101(Cr) foram formados. Evidências da incorporação dos diferentes componentes na estrutura dos materiais foram conseguidas pelo uso das espectroscopias nas regiões do infravermelho e ultravioleta e visível. Para os materiais contendo diferentes ligantes, observou-se um grau de incorporação de um dos ligantes substituídos de até aproximadamente 20%, apresentando áreas superficiais da ordem de 2300 mg. Já, para os materiais contendo diferentes metais, obteve-se uma incorporação de Fe(III) de até 17%. Além do mais, neste caso, alguns resultados mostram que há uma homogeneidade da distribuição de ferro nestes materiais. Desta forma, a partir do desenvolvimento deste trabalho, mostrou-se que o método de síntese utilizado foi bastante simples e eficiente para a produção de novos materiais que apresentam a estrutura do MIL-101, mas com superfícies com características e reatividade diferenciadas. / Abstract: This study explores modifications in the process of synthesis of a metal-organic framework known as MIL-101(Cr), formed by chromium(III) trinuclear clusters linked by terephthalate bridges. Through the use of reaction media containing a mixture of components (linkers or metals), we aimed the incorporation of different components in materials presenting MIL-101(Cr) structure. The products obtained from this approach were characterized by powder X-ray diffraction, where we could observe that materials isoreticular to MIL-101(Cr) were formed, depending on the composition of reaction medium. From infrared and ultraviolet and visible spectroscopies, the incorporation of the different components in the structures was confirmed. For the materials containing different linkers, we observed incorporation degrees up to 20% for one of the substituted linkers and these materials presented specific surface areas in the order of 2300 mg. For the systems containing different metals, we obtained incorporation degrees up to 17%. Moreover, some results show that iron centers are homogeneously distributed over the structures. In conclusion, we could show that this synthetic approach was very simple and efficient for the formation of novel materials that are isoreticular to MIL-101(Cr), but presenting surfaces with diverse characteristics and reactivity. / Mestrado / Quimica Inorganica / Mestre em Química
114

Oxitetraciclina no meio ambiente: sistema eletroanalítico de detecção, degradação e sorção em solução aquosa

de Oliveira Cunha, Cláudia 31 January 2011 (has links)
Made available in DSpace on 2014-06-12T23:15:16Z (GMT). No. of bitstreams: 2 arquivo920_1.pdf: 2966352 bytes, checksum: 64f5f0a198024542cf5cad637bd100b8 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Substâncias farmacêuticas têm sido recentemente reconhecidas como contaminantes emergentes quando presentes em concentrações mesmo a nível de ng ou μg nos rios e em espécies aquáticas, quer sejam zooplancton ou fitoplancton. Estas espécies devido às suas propriedades físico-químicas são persistentes e bioacumulativas no ambiente provocando efeitos negativos nos ecossistemas aquáticos ou terrestres. Dentre os grupos de fármacos, a oxitetraciclina (OTC), um antibiótico se mostra eficaz contra diversos microorganismos, com aplicação na medicina humana e veterinária. O objetivo deste trabalho foi desenvolver um eletrodo íon-seletivo para detecção de oxitetraciclina através de sistema de análise por injeção seqüencial, avaliar sua degradação aplicando processos oxidativos avançados, e avaliar o uso de rede de coordenação 3D para adsorver OTC de uma solução aquosa. Através de testes de seletividade foi possível desenvolver uma metodologia potenciométrica, utilizando na preparação da membrana sensora, dibutil ftalato (68%), PVC-COOH (31%), e β-ciclodextrina (1%). A incorporação desta membrana em sistemas de análise por injeção seqüencial conduziu a uma automatização dos procedimentos analíticos envolvidos na determinação de OTC.HCl em produtos farmacêuticos, proporcionando uma freqüência analítica de aproximadamente 51 amostras h-1 sendo possivel utilizar este sistema em análise de rotina. A degradação da oxitetraciclina em solução aquosa foi avaliada utilizando Processos Oxidativos Avançados. Obteve-se através da fotólise uma degradação de 54,7% utilizando lâmpada com 250W de potência após 60 minutos. Aplicando o processo H2O2/UV a degradação foi de 92,6% com uma lâmpada de 250W de potência e [H2O2] = 6 mmol, em 15 minutos. Na aplicação do Processo Fenton, obteve-se 69,0% na degradação, utilizando [Fe2+] = 0,05 mmol e [H2O2] = 6 mmol, em 6 minutos. O uso do Processo foto-Fenton, utilizando lâmpada de 250W de potência, [Fe2+] = 0,05 mmol e [H2O2] = 6 mmol, em 6 minutos, obteve-se uma degradação de 85,0%. Através do processo por fotocatálise (TiO2) a degradação do antibiótico foi de 98,3% com injeção de ar, utilizando luz negra (400-320nm), pH = 7 e [TiO2] = 1 g L-1, em 60 minutos de processo. No processo de remoção (%) da oxitetraciclina empregando Metal Organic Frameworks (MOF) houve remoção de 4,3 a 99,7%. O comportamento das MOFs ativadas apresentou uma menor eficiência em relação aos in natura . Analisando a MOF A100, a remoção e o equilíbrio da oxitetraciclina ocorreram de forma rápida (±20 min), tanto para a MOF in natura, quanto para a ativada. Já o comportamento de saturação da coluna utilizando a MOF C300 (C18H6Cu3O12) ocorreu de maneira acentuada para os dois tipos de adsorvente, ou seja, indicando o completo esgotamento da coluna (C/C0=1). A curva de saturação da MOF Z1200 (C8H12N4Zn) ocorreu de maneira mais suave, principalmente para o adsorvente in natura . Através da caracterização das MOFs por Infravermelho, observou-se que apenas a faixa no comprimento de onda correspondente a água (3000 a 3650 nm) para a MOF Z1200 é quase nula, como também, na análise por BET obteve-se uma maior área superficial e volume poroso, isso pode ter levado a uma melhor interação junto a OTC. Aplicando o planejamento fatorial com a Basolite Z1200 foi possível verificar que quanto maior for a massa e menor o tempo significa um aumento médio 16,8 e 13,3% na quantidade de remoção da oxitetraciclina, respectivamente
115

Investigating the Single Crystal to Single Crystal Transformations of Highly Porous Metal-Organic Frameworks Through the Crystalline Sponge Method

Brunet, Gabriel January 2016 (has links)
The development of a new technique capable of analyzing compounds crystallographically without first needing to crystallize them has been recently described. The present thesis aims to demonstrate the potential of such a technique, which utilizes crystalline sponges, in order to regularly order guest compounds in a porous media. The structural stability of the molecular sponges, which are highly porous metal-organic frameworks (MOFs), is first investigated, revealing that the Co-based MOF, 1, undergoes two remarkable transformations. This thesis also demonstrates how the technique can be employed to visualize the motion and occupancy of gaseous guests in a MOF. The Zn-based MOF, 4, was found to physisorb and chemisorb molecular iodine, leading to the formation of a variety of polyiodide species. The flexible nature of the host was determined to be an essential component in the exceptionally large iodine uptake capacity of the MOF. These results illustrate that the crystalline sponge method can be an effective strategy for directly visualizing guest molecules and obtaining vital information on the interactions formed between the host and guest.
116

Synthèses et propriétés thermiques et photophysiques de nouveaux polymères de coordination à base de CuX (X = Cl, Br, I) et de ligands mono- ou dithioéthers

Bonnot, Antoine January 2016 (has links)
La recherche sur la conception de nouveaux matériaux, dits intelligents, est en constant progrès depuis plus de 30 ans. Historiquement, les premiers matériaux utilisés et transformés par l’homme étaient le bois, les minéraux et ses dérivés (pierre, métaux, etc.). C’est à la fin du 19e siècle que la synthèse des polymères organiques et inorganiques ainsi que leurs utilisations se développèrent. Ce progrès continue de nos jours. Ainsi, c’est dans cette direction que cette thèse fut rédigée, l’étude de polymères de coordination basés sur le cuivre(I). Elle s’orchestra en six principales sections de recherche. La première section, i.e. le chapitre 2 traite de la coordination de différents ligands monothioéthers sur du CuX (X = I, Br) pour former plusieurs types de polymères de coordination (CPs). Ainsi, le CP 1D [(Me[indice inférieur 2]S)[indice inférieur 3]{Cu[indice inférieur 2]([mu]-I)[indice inférieur 2}][indice inférieur n] est obtenu quand CuI et Sme[indice inférieur 2] réagissent ensemble dans le n-heptane, alors qu’ils entrainent la formation du CP 2D [(Me[indice inférieur 2]S) [indice inférieur 3] {Cu[indice inférieur 4]([mu]-I) [indice inférieur 4]}] [indice inférieur n] dans le MeCN. Ce dernier contient des unités de construction secondaire (SBU ; Secondary Building Units en anglais) en forme de cluster Cu[indice inférieur 4]I[indice inférieur 4] « cubane partiellement ouvert ». En faisant réagir le MeSEt avec du CuI, le CP 2D [(MeSEt) [indice inférieur 2]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 2] ([mu][indice inférieur 2]-I) [indice inférieur 2]}(MeCN) [indice inférieur 2]] [indice inférieur n] contenant des SBUs de type Cu[indice inférieur 4]I[indice inférieur 4] « cubanes en escalier » a été isolé dans MeCN, alors qu’ils entrainent l’obtention du polymère 1D [(MeSEt) [indice inférieur 3]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}] [indice inférieur n] dans le n-heptane contenant quant à lui des clusters de types Cu[indice inférieur 4]I[indice inférieur 4] « cubanes fermés ». Alors que le traitement de MeSPr avec du CuI forme le CP 1D [(MeSPr) [indice inférieur 3]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}] [indice inférieur n], les composés [(L) [indice inférieur 4]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}] (L = EtSPr, Pr[indice inférieur 2]S) sont respectivement obtenus avec le EtSPr et le Pr[indice inférieur 2]S. À partir du [indice supérieur i]Pr[indice inférieur 2]S et de CuI, le cluster [([indice supérieur i]Pr[indice inférieur 2]S) [indice inférieur 6]{Cu[indice inférieur 8] ([mu][indice inférieur 3]-I) [indice inférieur 3]}([mu][indice inférieur 4]-I) [indice inférieur 2]}] est obtenu alors que l’on forme un CP 2D [(Cu[indice inférieur 3]Br[indice inférieur 3])(MeSEt) [indice inférieur 3]] [indice inférieur n] à partir de CuBr et MeSEt dans l’heptane. Ce dernier incorpore à la fois des Cu([mu][indice inférieur 2]-Br) [indice inférieur 2]Cu rhomboédriques et des SBUs de type Cu[indice inférieur 4]Br[indice inférieur 4] « cubanes ouverts ». Le MeSPr forme, quant à lui avec le CuBr dans l’heptane, le CP 1D [(Cu[indice inférieur 3]Br[indice inférieur 3])(MeSPr) [indice inférieur 3]] [indice inférieur n] qui, après recristallisation dans le MeCN, est converti en un CP 2D [(Cu[indice inférieur 5]Br[indice inférieur 5])([mu][indice inférieur 2]-MeSPr) [indice inférieur 3]] [indice inférieur n] incorporant des SBUs [(Cu[indice inférieur 5] ([mu][indice inférieur 4]-Br)([mu][indice inférieur 2]-Br)]. Les propriétés de stabilités thermiques et photophysiques de ces matériaux ont aussi été reportées.   Dans la section 2, i.e. au chapitre 3, les réactions entre des ligands dithioétherbutanes (1,4-bis(phénylthio)butane et 1,4-bis(cyclohexylthio)butane) avec CuX (X = Br, I) ont été étudiées. En faisant réagir les CuX avec le 1,4-bis(cyclohexylthio)butane, dans le ratio (1:1), les CPs 1D, peu luminescents, isostructuraux [(Cu[indice inférieur 2]X[indice inférieur 2])([mu]-CyS(CH[indice inférieur 2]) [indice inférieur 4])SCy) [indice inférieur 2]] [indice inférieur n] (X = Br, I) sont obtenus. Inversement, quand CuI réagit avec 1,4-bis(phénylthio)butane, dans le ratio (2:1), il se forme le préalablement reporté CP 2D [(Cu[indice inférieur 4]I[indice inférieur 4])([mu]- PhS(CH[indice inférieur 2]) [indice inférieur 4])SPh) [indice inférieur 2]] [indice inférieur n], alors qu’avec le CyS(CH[indice inférieur 2]) [indice inférieur 4])SCy, un nouveau composé luminescent est obtenu, mais sa structure n’a pas pu être résolue.(1) Les caractérisations habituelles en photophysique et en stabilité thermique ont été menées sur ces matériaux. Dans la troisième section, i.e. dans le chapitre 4, les réactions de coordination de CuX (Br, I) sur les ligands dithioétherbutènes E- et Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh, E- et Z-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol ont été comparées. Quand les sels CuX réagissent avec E-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh les CP 2D [Cu[indice inférieur 2]X[indice inférieur 2]{[mu]-E-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh}[indice inférieur 2]] [indice inférieur n] (X = I, Br), composés isostructuraux, sont obtenus. Incorporant une structure sans-précédente, ces réseaux sont formés à partir de couches 2D en alternance ABAB, contenants des SBUs Cu[indice inférieur 2] ([mu][indice inférieur 2]-X) [indice inférieur 2] rhomboédriques. Inversement, quand l’isomère Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh réagit avec des sels de CuX, deux structures différentes sont obtenues : le CP 2D [Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4] ([mu]-Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh}[indice inférieur 2]] [indice inférieur n] contenant des SBUs de type « cubane fermé » et le complexe 0D [Cu[indice inférieur 2]Br[indice inférieur 2]{[mu]-Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh}[indice inférieur 2]]. De par la réaction de E-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol avec CuI, le CP 2D [{Cu([mu][indice inférieur 3]-I)} [indice inférieur 2] ([mu]-E-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol)]n contenant des rubans parallèles en escalier est obtenu, alors que la structure issue de CuBr n’a pas pu être résolue. Finalement, quand CuX réagit avec Z-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol, les CPs 2D iso-structuraux [Cu[indice inférieur 2]X[indice inférieur 2]{[mu]-Z-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol}[indice inférieur 2]] (X = I, Br) sont formés. Dans ce cas, contrairement, aux premières structures obtenues, les couches de ces CPs sont composées de grilles incorporant des SBUs rhomboédriques Cu[indice inférieur 2] ([mu][indice inférieur 2]-X) [indice inférieur 2] dont les distances Cu···Cu sont identiques d’une couche à l’autre. Les caractérisations habituelles en photophysique et en stabilités thermiques ont été menées sur ces matériaux. De plus, des calculs théoriques ont été réalisés afin de mieux comprendre les propriétés photophysiques de ces composés. La quatrième section, i.e. le chapitre 5, traite des réactions de CuX (Br, I, Cl) sur des ligands dithioétherbutynes (1,4-bis(pTolthio)but-2-yne et 1,4-bis(benzylthio)but-2-yne. Quand CuBr réagit avec 1,4-bis(pTolthio)but-2-yne, le CP 1D [{Cu([mu][indice inférieur 2]-Br) [indice inférieur 2]Cu}([mu]-pTolSCH[indice inférieur 2]C≡CCH[indice inférieur 2]S-pTol) [indice inférieur 2]] [indice inférieur n] est obtenu, alors que le CP 2D [{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}([mu]-pTolSCH[indice inférieur 2]C≡CCH[indice inférieur 2]S-pTol) [indice inférieur 2]] [indice inférieur n], préalablement reporté, est formé.(2) La réaction des sels CuI et CuCl avec 1,4-bis(benzylthio)but-2-yne engendre la formation de complexes isomorphes 0D [{Cu([mu][indice inférieur 2]-X) [indice inférieur 2]Cu}([mu]-PhCH[indice inférieur 2]SCH[indice inférieur 2]C≡CCH[indice inférieur 2]SCH[indice inférieur 2]Ph) [indice inférieur 2]] (X = I, Br). Contrairement à l’utilisation de CuCl, qui avec PhCH[indice inférieur 2]SCH[indice inférieur 2]C≡CCH[indice inférieur 2]SCH[indice inférieur 2]Ph forme le CP 2D [{Cu[indice inférieur 2] ([mu][indice inférieur 2]-Cl)([mu] [indice inférieur 3]-Cl)}([mu]-PhCH[indice inférieur 2]SCH[indice inférieur 2]C≡CCH[indice inférieur 2]SCH[indice inférieur 2]Ph)] [indice inférieur n]. Notons que ce CP présente des propriétés de photophysique peu communes pour un dérivé chloré, car il émet de la lumière autour de 600 nm. La cinquième section, i.e. le chapitre 6, traite des réactions de CuI avec PhS(CH[indice inférieur 2]) [indice inférieur 8]SPh et pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol qui génèrent respectivement les CPs luminescents 1D [Cu[indice inférieur 4]I[indice inférieur 4]{[mu][indice inférieur 2]-PhS(CH[indice inférieur 2]) [indice inférieur 8]SPh}[indice inférieur 2]] [indice inférieur n] et 2D [Cu8I8{[mu]2-pTolS(CH2)8S-pTol}3(MeCN)2]n. Le CP 2D [Cu8I8{[mu]2-pTolS(CH2)8S-pTol}3 (MeCN)2]n présente un réseau qui n’avait jamais été rencontré dans la littérature auparavant, c.-à-d., des couches de polymère construites à partir de deux cubanes fermés pontés ensemble par un rhomboèdre comme SBUs. Leurs propriétés physiques et de stabilités thermiques ont été étudiées et présentent quelques différences notables. La sixième section, i.e. le chapitre 7, traite des réactions entre CuI avec le ligand flexible pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol dans le MeCN ou EtCN et p-[indice supérieur t]BuC[indice inférieur 6]H[indice inférieur 4]S(CH[indice inférieur 2]) [indice inférieur 8]SC[indice inférieur 6]H[indice inférieur 4]-p-[indice supérieur t]Bu L2 dans EtCN. Les synthèses issues de pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol permettent l’obtention de CPs 2D [Cu[indice inférieur 8]I[indice inférieur 8]{pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol}[indice inférieur 3] (solvant) [indice inférieur 2]] [indice inférieur n] (1•MeCN et 1•EtCN) contenant des nœuds de connexion de type Cu[indice inférieur 8]I[indice inférieur 8]. Par opposition, l’utilisation du ligand p-[indice supérieur t]BuC[indice inférieur 6]H[indice inférieur 4]S(CH[indice inférieur 2]) [indice inférieur 8]SC[indice inférieur 6]H[indice inférieur 4]-p-[indice supérieur t]Bu dans EtCN entraine la formation d’un CP 1D [Cu[indice inférieur 4]I[indice inférieur 4]{p-[indice supérieur t]BuC[indice inférieur 6]H[indice inférieur 4]S(CH[indice inférieur 2]) [indice inférieur 8]SC[indice inférieur 6]H[indice inférieur 4]-p-[indice supérieur t]Bu}[indice inférieur 2] (EtCN) [indice inférieur 2]] [indice inférieur n] incorporant les SBUs de type cubane fermé. Les CPs 2D 1•MeCN et 1•EtCN, contrairement à 2•EtCN, présentent l’habilité de pouvoir perdre le solvant initialement incorporé dans leur structure sous vide et de le readsorber ou d’adsorber un autre solvant, chose qui peut être suivie à l’aide de la variation de la luminescence, la stabilité thermique, ou encore par diffraction des rayons X sur poudre. La septième section, i.e. le chapitre 8 traite des réactions, une fois encore, entre un ligand dithioéther, contenant un pont flexible butane (EtS(CH[indice inférieur 2]) [indice inférieur 4]SEt) et les sels CuX (X = I, Br). Dans ce cas, il se forme avec le CuI un CP luminescent 2D [Cu[indice inférieur 4]I[indice inférieur 4]{[mu]-EtS(CH[indice inférieur 2]) [indice inférieur 4]SEt}[indice inférieur 2]] [indice inférieur n], alors qu’il génère avec CuBr, le CP 3D [(Cu[indice inférieur 2]Br[indice inférieur 2]){[mu]-EtS(CH[indice inférieur 2]) [indice inférieur 4]SEt}][indice inférieur n] faiblement luminescent, construit sur des couches en parallèle pontées par les soufres doublement n-donneurs. Il est intéressant de remarquer qu’une migration de l’énergie d’excitation se produit dans le CP 3D (dérivé bromé) contrairement au CP 2D (dérivé iodé) sous excitation de haute intensité. Très peu d’exemples présentent ce type de processus parmi tous les CPs ( < 10). Pour conclure, les réactions entre les sels CuX (X = Cl, Br, I) avec des ligands thioéthers de types différents (mono-, di-thio, rigide ou flexible) peuvent offrir des matériaux de structures variables (CP 0D, 1D, 2D, 3D avec et sans cavités) présentant leurs propres spécificités (luminescence, stabilité thermique, adsorption de gaz, solvatochromisme, etc.). Le résultat le plus important à noter, en comparaison avec la littérature est, qu’il est très difficile, voire impossible, de pouvoir prédire la dimensionnalité, la structure et les propriétés dont résultera la coordination des ligands thioéthers sur des sels de CuX (X = Cl, Br, I). Par conséquent, de nombreuses combinaisons et études restent encore à être menées pour mieux comprendre ces matériaux et trouver la, ou les meilleures combinaisons possibles pour concevoir des MOFs luminescents à partir de CuX.
117

Organic-Inorganic Hybrid Materials Based on Oxyanion Linkers for Selective Adsorption of Polarizable Gases

Mohamed, Mona Hanafy 01 January 2015 (has links)
The separation of industrially important gases into pure supplies that can be used for many practical applications is based mainly on energy intensive methods such as the cryogenic distillation which is costly and energy intensive. Therefore other routes have been introduced to industrial separation of gases such as the selective adsorption using porous solid materials. Zeolites and activated carbon are the most widely used recyclable energy-efficient porous solid materials for industrial gas separations, however the low uptake and selectivity hurdles their commercialization in some separation applications. Metal organic frameworks (MOFs) have been extensively studied as solid porous materials in term of gas separations nevertheless the future of MOFs for practical gas separations is considered to be vague and stringent due to their low stability, low capacity and selectivity especially at low partial pressures of the adsorbed gas, the competitive adsorption of the contaminants such as H2O, NOX and SOX, high cost of the organic ligands, besides the challenges of the formulation of MOFs which is very important in the MOFs marketing. In this context we present new porous materials based on inorganic linkers as well as the organic molecules, Organic-Inorganic Hybrid Materials, which were found to conquer the current challenges for the exploitation of MOFs in practical gas separation such as separation of trace and low CO2 concentrations and Xe separation from Xe/Kr mixtures. The work presented herein encompasses the development of novel 48.67 topology metal organic material (MOM) platform of formula [M(bp)2(M'O4)] (M= Co or Ni; bpe= bipyridine-type linkers; M'= W, Mo or Cr) that have been assigned RCSR code mmo based upon pillaring of [M(bp)2] square grids by angular WO42-, MoO42- or CrO42- pillars. Such pillars are unexplored in MOMs. They represent ideal platforms to test the effect of pore size and chemistry upon gas sorption behavior since they are readily fine-tuned and can be varied at their 3-positions (metal, organic linker and the inorganic pillar) without changing the overall structure. Such an approach allows for systematic control of pore size to optimize interactions between the framework and the adsorbent in order to enhance selectivity and/or gas uptake. Interestingly, these nets showed a high chemical stability in air, water, boiling water and in a wide range of pH which is certainly a desirable property in industry and commercialization of MOMs. [Ni(bpe)2(MoO4)] (bpe= 1,2-bis(4-pyridyl) ethane), MOOFOUR-1-Ni, and its chromate analog, CROFOUR-1-Ni, exhibit remarkable CO2 affinity and selectivity, especially at low loading. This behavior can be attributed to exceptionally high isosteric heats of adsorption (Qst) of CO2 in MOOFOUR-1-Ni and CROFOUR-1-Ni of ~56 and ~50 kJ/mol, respectively, at zero loading. These results were validated by modeling which indicate that the electrostatics of such inorganic anions towards CO2 affords favourable attractions to CO2 that are comparable to the effect of unsaturated metal centres. The use of WO42- instead of CrO42- or MoO42- as an angular pillar in mmo topology nets has afforded two isostructural porous nets of formula [M(bpe)2WO4] (M = Co or Ni, bpe=1,2-(4-pyridyl)ethene). The Ni variant, WOFOUR-1-Ni, is highly selective towards CO2 thanks to its exceptionally high isosteric heat of adsorption (Qst) of -65.5 kJ/mol at zero loading. The fine-tunability and the inherent modularity of this platform allow us exquisite design and control over the pore chemistry through the incorporation of different functionalities inside the channels of the networks which was then demonstrated as valuable strategy in terms of carbon dioxide capture at condition relevant to the direct CO2 capture from air. The exploitation of 4,4'-azopyridine in the design and synthesis of CROFOUR-2-Ni, an isostructure of CROFOUR-1-Ni, affords a paradigm shift in the CO2 adsorption properties as exemplified by the enhanced CO2 isosteric heat of adsorption at moderate and high loading in CROFOUR-2-Ni and the superior CO2 selectivity even for trace and low CO2 concentration. The two isostructures, CROFOUR-1-Ni and CROFOUR-2-Ni have been also investigated in term of Xe adsorption and separation from Xe/Kr mixtures. The two structures were found to exhibit the remarkable Xe affinity and selectivity which, together with high stability, good recyclability, low regeneration energy and low cost of the two materials could not only diminish the cost of the Xe and Kr production but also can potentially afford a high purity of the separated gases.
118

Lanthanide Metal-Organic Frameworks and Hierarchical Porous Zeolitic Imidazolate Frameworks : Synthesis, Properties, and Applications

Abdelhamid, Hani Nasser January 2017 (has links)
This thesis presents the synthesis, properties, and applications of two important classes of metal-organic frameworks (MOFs); lanthanide MOFs and hierarchical porous zeolitic imidazolate frameworks (ZIFs). The materials have been characterized using a wide range of techniques including diffraction, imaging, various spectroscopic techniques, gas sorption, dynamical light scattering (DLS) and thermogravimetric analysis (TGA). In Chapter 1, the unique features of MOFs and ZIFs as well as their potential applications are summarized. In Chapter 2, different characterization techniques are presented. Chapter 3 describes a family of new isoreticular lanthanide MOFs synthesized using tri-topic linkers of different sizes, H3L1-H3L4, denoted SUMOF-7I-IV (Ln) (SU; Stockholm University, Ln = La, Ce, Pr, Nd, Sm, Eu and Gd, Paper I). The SUMOF-7I-III (Ln) contain permanent pores and exhibit exceptionally high thermal and chemical stability. The luminescence properties of SUMOF-7IIs are reported (Paper II). The influences of Ln ions and the tri-topic linkers as well as solvent molecules on the luminescence properties are investigated. Furthermore, the potential of SUMOF-7II (La) for selective sensing of Fe (III) ions and the amino acid tryptophan is demonstrated (Paper III).  Chapter 4 presents a simple, fast and scalable approach for the synthesis of hierarchical porous zeolitic imidazolate framework ZIF-8 and ZIF-67 using triethylamine (TEA)-assisted approach (Paper IV). Organic dye molecules and proteins are encapsulated directly into the ZIFs using the one-pot method. The photophysical properties of the dyes are improved through the encapsulation into ZIF-8 nanoparticles (Paper IV). The porosity and surface area of the ZIF materials can be tuned using the different amounts of dye or TEA. To further simplify the synthesis of hierarchical porous ZIF-8, a template-free approach is presented using sodium hydroxide, which at low concentrations induces the formation of zinc hydroxide nitrate nanosheets that serve as in situ sacrificial templates (Chapter 5, Paper V). A 2D leaf-like ZIF (ZIF-L) is also obtained using the method. The hierarchical porous ZIF-8 and ZIF-L show good performance for CO2 sorption. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Manuscript.</p>
119

Star Shaped Thieno- and Thienylaryls as Multifunctional Materials

Robertson, Sean January 2015 (has links)
The work in this thesis was undertaken to explore both the effect of heteroatoms on the semiconducting properties of star-shaped thienoacenes, and to expand the scope of these materials to fields outside of organic semiconductors. Overall, new star-shaped molecules were prepared with a view towards applications such as thin film transistors, as the organic linker component in metal-organic frameworks, and as ligands that could coordinate to transition metals through the sulfur atom. The first chapter describes the properties of star-shaped molecules, the theory underlying their semiconducting behaviour, and the previous work that motivated the research contained herein. The second chapter of this thesis outlines the synthetic methodology that was utilized to achieve the molecular targets, as well as the characterization techniques that are used to reveal the properties of organic semiconductors. The third chapter of this thesis describes the synthesis and optoelectronic properties of novel nitrogen-containing semiconductor molecules called thienoacridines, and their comparison to carbon-and-sulfur based analogues, thienoanthracenes. The fourth and fifth chapters concern the synthesis of functionalized star shaped thienylbenzene molecules. In Chapter 4, these molecules are decorated with carboxylic acid groups so that they may act as tetrapodal MOF linkers. In Chapter 5, they are equipped with N-aryl(azomethine)thiophene moieties to explore sulfur coordination and act as ligands. The sixth chapter provides conclusion to this work, and possible future directions of the research conducted herein.
120

Computational High Throughput Screening of Metal Organic Frameworks for Carbon Dioxide Capture and Storage Applications

Boyd, Peter G. January 2015 (has links)
This work explores the use of computational methods to aid in the design of Metal Organic Frameworks (MOFs) for use as CO2 scrubbers in carbon capture and storage applications. One of the main challenges in this field is in identifying important MOF design characteristics which optimize the complex interactions governing surface adsorption. We approach this in a high-throughput manner, determining properties important to CO2 adsorption from generating and sampling a large materials search space. The utilization of MOFs as potential carbon scrubbing agents is a recent phenomenon, as such, many of the computational tools necessary to perform high-throughput screening of MOFs and subsequent analysis are either underdeveloped or non-existent. A large portion of this work therefore involved the development of novel tools designed specifically for this task. The chapters in this work are contiguous with the goal of designing MOFs for CO¬2 capture, and somewhat chronological in order and complexity, meaning as time and expertise progressed, more advanced tools were developed and utilized for the purposes of computational MOF discovery. Initial work towards MOF design involved the detailed analysis of two experimental structures; CALF-15 and CALF-16 using classical molecular dynamics, grand canonical Monte Carlo simulations, and DFT to determine the structural features which promote CO2 adsorption. An unprecedented level of agreement was found between theory and experiment, as we are able to capture, with simulation, the X-ray resolved binding sites of CO2 in the confined pores of CALF-15. Molecular simulation was then used to provide a detailed breakdown of the energy contributions from nearby functional groups in both CALF-15 and CALF-16. A large database of hypothetical MOF structures is constructed for the purposes of screening for CO2 adsorption. The database contains 1.3 million hypothetical structures, generated with an algorithm which snaps together rigid molecular building blocks extracted from existing MOF crystal structures. The algorithm for constructing the hypothetical MOFs and the building blocks themselves were all developed in-house to form the resulting database. The topological, chemical, and physical features of these MOFs are compared to recently developed materials databases to demonstrate the larger structural and chemical space sampled by our database. In order to rapidly and accurately describe the electrostatic interactions of CO2 in the hypothetical database of MOFs, parameters were developed for use with the charge equilibration method. This method assigns partial charges on the framework atoms based on a set of parameters assigned to each atom type. An evolutionary algorithm was used to optimize the charge equilibration parameters on a set of 543 hypothetical MOFs such that the partial charges generated would reproduce each MOFs DFT-derived electrostatic potential. Validation of these parameters was performed by comparing the CO2 adsorption from the charge equilibration method vs DFT-derived charges on a separate set of 693 MOFs. Our parameter set were found to reproduce DFT-derived CO2 adsorption extremely well using only a fraction of the time, making this method ideal for rapid and accurate high-throughput MOF screening. A database of 325,000 MOFs was then screened for CO2 capture and storage applications. From this study we identify important binding pockets for CO2 in MOFs using a binding site analysis tool. This tool uses a pattern recognition method to compare the 3-D configurations of thousands of pore structures surrounding strong CO2 adsorption sites, and present common features found amongst them. For the purposes of developing larger databases which sample a more diverse materials space, a novel MOF construction tool is devloped which builds MOFs based on abstract graphs. The graph theoretical foundations of this method are discussed and several examples of MOF construction are presented to demonstrate its use. Notably, not only can it build existing MOFs with complicated geometries, but it can sample a wide range of unique structures not yet discovered by experimental means.

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