Universiẗat, Diss.--Münster, 1999.

Conventional xanthene dyes (eg: fluorescein and rhodamine) have their absorptions and emissions in the visible region, which limits their use in cellular imaging. Absorptions and emissions at longer wavelengths allow for low background cellular autofluorescence, deep tissue penetration, and minimum cell damage. Chapter I discusses the background of fluorescent dyes and the importance of near-infrared (NIR) emissive dyes for biological applications. Chapter II is based on the design and synthesis of new xanthene-based NIR I dyes using simple and short synthetic routes. This study used pyrrole and indole as donor molecules and combined them to the xanthene core by the Suzuki cross-coupling reaction to prepare the new dyes. After the treatment with trifluoroacetic acid, these new dyes transformed from their non-fluorescent to fluorescent forms and exhibited excellent red shifts in their maximum absorption and emission wavelengths. The novel pyrrole-based xanthene dye was used to investigate the efficacy of the dye as a probe for fluoride ions. We were able to modify this dye with a silyl ester receptor and develop a probe as a colorimetric turn-off fluoride ion sensor. In chapter III, we describe the synthesis of different NIR emissive xanthene dyes using the donor-acceptor-donor concept. New xanthene-based dyes were designed with five-membered heterocycles and fused heteronuclear molecules. Additionally, xanthene-based dyes containing an alkyne spacer were synthesized using the D-pi-A model to extend the pi-conjugation through the alkyne spacer. All of the dyes exhibited absorption and emission maxima in the visible to NIR I region, between 500-850 nm. In chapter IV, we discussed the synthesis of xanthene-based electrochromic materials. These compounds used xanthene as the chromophore and ferrocene as the electrophore units. Novel rhodamine-based symmetric and unsymmetric dyes were synthesized by attaching the ferrocene unit through the lactam ring. The compounds were then investigated as an electrochromic probe using UV-Vis, cyclic voltammetry, and spectroelectrochemical analysis.

xviii, 242 p. : ill. (some col.) / Fuel purification is an extremely active area of research in today's green world. Specifically, desulfurization of fuels is an important area of research for two reasons. First, any sulfur present in fuels generates SOx pollutants that are hazardous to human health and also contribute to acid rain. Secondly, even trace sulfur contaminants prohibit the use of fuel streams in fuel cells. However, achieving near-zero sulfur levels with existing technology is impractical. The work in this thesis investigates a new process for the removal of sulfur from fuel streams using a film-shear reactor (based on a process known as oxidative desulfurization), and goes on to investigate the mode of activation for the process within the reactor through a study of the reactor conditions. Additionally, other applications of the film-shear reactor, including mechanical activation of molecules and controlled nanoparticle synthesis are explored. Chapter I outlines the current status of oxidative desulfurization research, highlighting the strengths of the method, innovative approaches and drawbacks to the various approaches. Chapters II and III go on to discuss the enhancement of the process in the film-shear reactor using model fuels and a variety of substrates. This method was found to significantly enhance the oxidative desulfurization process, reducing both the time and temperature required to achieve considerable sulfur removal. Levels of desulfurization that require hours at elevated temperatures by conventional stirring methods were obtainable on the scale of seconds at or below room temperature. Chapter IV offers investigations into the conditions within the film-shear reactor, and also presents studies of the ability of the high shear rates obtained in the reactor to mechanically activate molecules. Chapter V extends the applicability of the film-shear reactor to nanoparticle synthesis through investigation of two titania synthesis methods utilizing the film-shear reactor. Appendices A and B offer supplementary information to enhance the studies presented in Chapters II and III, while Appendices C, D, and E highlight work done investigating the ability of platinum complexes to hydrate nitriles and cyanohydrins. This dissertation includes previously published and unpublished co-authored material. / Committee in charge: Victoria J. DeRose, Chairperson; David R. Tyler, Advisor; Kenneth M. Doxsee, Member; Catherine J. Page, Member; Mark H. Reed, Outside Member

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A exigÃncia de um maior controle na emissÃo de poluentes de automÃveis, com uma reduÃÃo na emissÃo de enxofre, tem levado a um intenso esforÃo de pesquisas sobre tÃcnicas de remoÃÃo de sulfurados nos combustÃveis. Nos Ãltimos anos, a adsorÃÃo à vista como uma tÃcnica alternativa adequada para atingir os nÃveis de dessulfurizaÃÃo das correntes das unidades de processo de hidrodessulfurizaÃÃo (HDS). O processo HDS à muito eficiente na remoÃÃo de mercaptanas e dissulfetos, porÃm maior severidade seria necessÃria para converter as molÃculas cÃclicas de enxofre, tais como tiofenos e benzotiofenos. Devido ao tamanho volumoso destes compostos refratÃrios de enxofre, adsorventes mesoporosos sÃo vistos como mais adequado para a adsorÃÃo do que sÃlidos microporosos convencionais, tais como zeÃlitas. A dessulfurizaÃÃo por adsorÃÃo com adsorventes modificados e seletivos à um processo alternativo promissor com relaÃÃo à hidrodessulfurizaÃÃo convencional por se tratar de um processo que nÃo necessita de condiÃÃes severas de operaÃÃo que comprometam a octanagem da gasolina e o custo final de operaÃÃo. Neste trabalho foi realizado um estudo de remoÃÃo de enxofre a partir de soluÃÃes de benzotiofeno em iso-octano, utilizando os adsorventes SBA-15 e SBA-15/PdCl2. Ãrea superficial BET, volume de poros e diÃmetro de poro dos materiais mesoporos, SBA-15 e SBA-15/PdCl2, foram medidos. A adsorÃÃo do benzotiofeno em iso-octano foi avaliada atravÃs do estudo dinÃmico usando uma coluna de leito fixo em escala de laboratÃrio, utilizando os adsorventes SBA-15 e SBA-15/PdCl2. Para a SBA-15/PdCl2 o estudo de adsorÃÃo em leito fixo foi realizado em quatro temperaturas: 25, 35, 45 e 60ÂC. Curvas de breakthrough foram simuladas de acordo com um modelo matemÃtico que considera as seguintes hipÃteses: operaÃÃo isotÃrmica, fluxo com dispersÃo axial, taxa de fluxo constante, resistÃncia à transferÃncia de massa externa Ãs partÃculas (filme) desprezÃvel, transferÃncia de massa descrita por uma aproximaÃÃo de forÃa motriz linear (LDF), isoterma de adsorÃÃo linear e equilÃbrio de adsorÃÃo atingido instantaneamente na superfÃcie externa das partÃculas adsorventes. Os resultados confirmaram a eficiÃncia da SBA-15/PdCl2 para a utilizaÃÃo em processos de adsorÃÃo de compostos sulfurados. / The demand of a larger control in the emission of pollutants from automobiles, with a reduction in the emission of sulfur, has led to an intense research effort on techniques of sulfur removal from fuels. In the last few years, adsorption is thought to be a suitable polishing technique to achieve a deep desulfurization of streams from hydrodesulfurization (HDS) units. The HDS process is very efficient in the removal of mercaptans and disulfides but higher severity would be required to convert cyclic sulfur molecules, such as tiophenes and benzotiophenes. Due to the bulky size of these refractory sulfur compounds, mesoporous adsorbents are thought to be best suited for adsorption than conventional microporous solids, such as zeolites. The desulfurization by adsorption with modified and selective sorbents is a promising alternative process when compared to the conventional hydrodesulfurization once that process does not need severe conditions of operation which compromise the octane of the gasoline and the final cost of operation. In this present work, a study was coducted to remove sulfur from benzothiophene solutions in isooctante, using the adsorbent SBA-15 and SBA-15/PdCl2. BET surface area, pore volume and pore diameter of SBA-15 and SBA-15/PdCl2 mesoporous materials were measured. Adsorptive desulfurization in benzothiophene/isooctane mixture was carried trough dynamic study using a column of fixed bed in laboratory scale, using sorbents SBA-15 and SBA-15/PdCl2. The adsorption study using SBA-15/PdCl2 was carried on four temperatures: 25, 35, 45 and 60ÂC. Breakthrough curves were simulated according to a mathematical model that assumes the following hypotheses: isothermal operation; flow with axial dispersion; constant fluid flow rate; negligible external film resistance to mass transfer; internal mass transfer described by LDF approximation; linear adsorption isotherm and equilibrium reached instantaneously at the external surface of adsorbent particles. The results confirmed the efficiency of SBA-15/PdCl2 for use in adsorption process of sulfur compounds.

Trois dérivés d’amino acides sont reconnus d’une manière stéréo sélective par l’albumine du sérum bovin. Cette propriété a été observée dans le cas de la phosphatase alcaline de tissu non spécifique, (TNAP). Des inhibiteurs agissant à trois niveaux distincts sur les processus de minéralisation ont été cherchés: 1) TNAP ; 2) Formation de l’hydroxyapatite (HA); 3) Vésicules maticielles (VMs). Nous avons trouvé que des dérivés de benzothiophènes et de tétramisoles, solubles dans l’eau, sont des inhibiteurs spécifiques de TNAP. Un modèle qui permet de produire du HA, a été développé et a confirmé que les nucléotides sont des inhibiteurs de formation de HA. Nous avons montré que le médicament anti-rhumatisme sinomenine, n’ayant aucun effet sur le TNAP, ainsi que la théophylline ralentissaient tous les deux la formation de HA induits par les VMs. Ces modèles de minéralisation présentent un grand potentiel lors du criblage de médicaments pour le traitement de l’ostéoarthrose / Three amino acid derivatives were stereoselectively recognized by bovine serum albumin. Such property was also observed in the case of tissue non-specific alkaline phosphatase (TNAP), a marker in mineral formation. Inhibitors acting at three distinct levels on mineral formation were searched: 1) TNAP; 2) Hydroxyapatite (HA) formation; 3) Matrix vesicle (MV). We found that benzothiophene derivative of tetramisole are water soluble inhibitors of TNAP. A model producing HA as MVs was developed and served to screen HA inhibitors, confirming that several nucleotides inhibited HA formation. We demonstrated that the anti-rheumatic Chinese medicine sinomenine, having no effect on TNAP and theophylline, slowed down HA induced by MVs. The mineralization models presented a great potential to screen putative drugs to cure ostoarthritis.

There has been increasing interest in the development of organic materials due to their unique structural and electronic properties. Organic compounds have the advantage of being able to be deposited from solution, leading to low-cost, high-area electronics production. Contorted polycyclic aromatic hydrocarbons have been shown to have potential for use in organic field-effect transistors (OFETs) and organic photovoltaic devices (OPVs) due to their supramolecular properties and charge carrier mobilities. Thiophene-based materials have also shown great promise in OFETs due to their high charge carrier mobilities, stability during device operation, solubility in organic solvents, and structural versatility. [n]Circulenes are a class of polycyclic aromatic compounds whose shape depends on the central n-membered ring. These range from bowl-shaped when n < 6, planar when n = 6, and saddle-shaped when n > 6. The shapes of these molecules, especially for the contorted circulenes, imparts interesting and useful properties such as a polarizable π-system and coordination to fullerenes. Using methods developed in our group, synthesis of [12]circulene derivatives was attempted. Synthetic difficulties, results, and a synthetic plan to overcome these problems are presented herein. 2,7-Dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) is a thiophene-based p-type semiconducting material with one of the highest reported OFET mobility to date. Alterations to BTBT have been made to improve device processing and tune the electronic structure. However, structural alterations have generally been limited to functionalization with electron-donating groups and extension of the π-system. The lack of electron deficient derivatives has prevented further tuning of the electronic structure. Additionally, installation of strongly electron-withdrawing substituents could give BTBT n-type character as seen with perylene diimides. Several synthetic strategies to develop BTBTs with electron-withdrawing groups were explored. Limitations to developing electron deficient BTBTs as well as synthesis and characterization of novel imide-functionalized derivatives are described.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aimed to use Multiple Walls Nanotubes (MWNT) in order to synthesize a nanofilter to remove water contaminants and to test the nanofilter manufactured in removing Benzothiophene and pesticides present in water. The study was conducted in two stages. In the first step the nanofilter was developed and characterized. To develop the filter, the following materials were used: Chitosan, Polyethylene Glycol 6000 K, Sodium Hydroxide (NaOH), Sodium Dodecyl Sulphate (SDS), Acetic Acid Glacial and MWNT. To characterize the filter was performed: Scanning Electron Microscopy (SEM), Raman spectroscopy, the method of Brunauer, Emmett and Teller (BET) method Barrett, Joyner and Halenda (BJH) and permeate flow. In the second step, removal efficiency of benzothiophene and pesticides by the nanofilter was tested. For this experimental activity, it was split into two steps: filtering with benzothiophene and other pesticides. For filtering with benzothiophene, it was prepared a solution with a concentration of 0.79 ± 0.02 mmol in triplicate, where 5 samples were filtered with the same concentration of 3 similar nanofilters. For the filtering of pesticides, it was prepared one stock solution of 10.0 mL (1000.0 mg L-1) Imazapic, Imazethapyr, Imidacloprid, Ethyl Pirazolsulfuron). For pesticide analysis, it was used the Ultra Efficiency Liquid Chromatography coupled to Mass Spectrometry in series (UHPLC-MS / MS). The chromatographic conditions were established by LARP-UFSM. From the results obtained on the characterization, it can be said that the filter is characterized by low permeability and average pore radius of 15 A0. Carbon nanotubes are maintained after the manufacturing process and nanofilter may be used for removal of contaminants in water. As for the results of efficiency, nanofilter remove benzothiophene present in water with high efficiency. In addition, the nanofilter removes pesticides in water even at concentrations 10 times higher than those found in natural environment. / Este trabalho teve como objetivo utilizar Nanotubos de Carbono de Paredes Múltiplas (NTCPM) para a confecção de nanofiltros para remoção de contaminantes em água, bem como testar o nanofiltro fabricado na remoção de Benzotiofeno e agrotóxicos presentes em água. O estudo foi realizado em dois capítulos. No primeiro capitulo foi desenvolvido e caracterizado o nanofiltro. Para desenvolver o nanofiltro, foram utilizados os seguintes materiais: Quitosana, Polietileno Glicol 6000 K, Hidróxido de Sódio (NaOH), Dodecil Sulfato de Sódio (SDS), Ácido Acético Glacial e NTCPM. Em Sua caracterização foram realizados as seguintes análises: Microscopia Eletrônica de Varredura (MEV), Espectroscopia Raman, método de Brunauer, Emmett e Teller (BET), método de Barrett, Joyner e Halenda (BJH) e Fluxo Permeado. No segundo capítulo, a eficiência na remoção de Benzotiofeno e agrotóxicos pelo nanofiltro foi testada. Para isto, a atividade experimental foi dividida em duas etapas: uma filtragem com Benzotiofeno e outra filtragem com agrotóxicos. Para filtragem com benzotiofeno, foi preparada uma solução com concentração de 0,79 ± 0,02 mmol em triplicata, onde 5 amostras com mesma concentração foram filtradas por 3 nanofiltros semelhantes. Para a filtragem dos agrotóxicos, foi preparada uma solução 10,0 mL da solução estoque 1000,0 mg L-1 de Imazapique, Imazetapir, Imidacloprido, Pirazolsulfuron Etílico. Para análise dos agrotóxicos foi utilizado a Cromatografia Líquida de Ultra Eficiência acoplada à Espectrometria de Massas em série (UHPLC-MS/MS). As condições cromatográficas foram estabelecidas pelo LARP-UFSM. A partir dos resultados obtidos, sobre a caracterização, pode-se afirmar que o filtro se caracteriza por baixa permeabilidade e raio médio dos poros com 15 Ao. Os nanotubos de carbono são mantidos após processo de fabricação e o nanofiltro poderia ser usado para remoção de contaminantes na água. Já para os resultados de eficiência, o nanofiltro remove o Benzotiofeno presente em água com alta eficiência. Além disso, o nanofiltro remove agrotóxicos em água mesmo com concentrações 10 vezes acima da encontrada em ambiente natural.

Trois dérivés d'amino acides sont reconnus d'une manière stéréo sélective par l'albumine du sérum bovin. Cette propriété a été observée dans le cas de la phosphatase alcaline de tissu non spécifique, (TNAP). Des inhibiteurs agissant à trois niveaux distincts sur les processus de minéralisation ont été cherchés: 1) TNAP ; 2) Formation de l'hydroxyapatite (HA); 3) Vésicules maticielles (VMs). Nous avons trouvé que des dérivés de benzothiophènes et de tétramisoles, solubles dans l'eau, sont des inhibiteurs spécifiques de TNAP. Un modèle qui permet de produire du HA, a été développé et a confirmé que les nucléotides sont des inhibiteurs de formation de HA. Nous avons montré que le médicament anti-rhumatisme sinomenine, n'ayant aucun effet sur le TNAP, ainsi que la théophylline ralentissaient tous les deux la formation de HA induits par les VMs. Ces modèles de minéralisation présentent un grand potentiel lors du criblage de médicaments pour le traitement de l'ostéoarthrose

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / No presente estudo foram preparados materiais carbonosos modificados mediante a impregnaÃÃo de metais (cobre, prata e palÃdio) para a remoÃÃo de enxofre a partir de soluÃÃes sintÃticas de benzotiofeno numa concentraÃÃo de 50 a 400ppm em iso-octano e em amostras de gasolina comercial. A adsorÃÃo do benzotiofeno em soluÃÃo de iso-octano (mistura modelo) foi avaliada atravÃs de experimentos em coluna de leito fixo recheada com carbonos ativados com e sem impregnaÃÃo de metais em trÃs temperaturas distintas: 30, 45 e 60ÂC. Curvas de breakthrough foram simuladas de acordo com um modelo matemÃtico que considera operaÃÃo isotÃrmica, equilÃbrio de adsorÃÃo nÃo linear, fluxo com dispersÃo axial e transferÃncia de massa descrita por uma aproximaÃÃo de forÃa motriz linear (LDF). Os resultados confirmaram a eficiÃncia da utilizaÃÃo dos carbonos ativados em processos de adsorÃÃo de compostos sulfurados, principalmente quando se modifica sua superfÃcie com metais. Foram obtidas capacidades mÃximas de adsorÃÃo significativas para os materiais utilizados de 1,08 mmol S/gads para o carbono ativado GF45; 2,00 mmolS/gads para o carbono ativado GF45/CuCl2; 2,38 mmolS/gads para o carbono ativado GF45/AgCl e 2,71 mmolS/gads para o carbono ativado GF45/PdCl2, quando se utilizou a mistura modelo. Para a gasolina real, obtiveram-se 0,14 mmolS/gads para o carbono ativado GF45/AgCl, 0,23 mmolS/gads para o carbono ativado GF45, 0,30 mmolS/gads para o carbono ativado GF45/CuCl2 e 1,00 mmolS/gads para o carbono ativado GF45/PdCl2, evidenciando uma melhoria ao se trabalhar na adsorÃÃo com materiais impregnados com metais. Em termos de seletividade foi observado um maior valor para este parÃmetro nos estudos realizados com o carbono impregnado com palÃdio. Com relaÃÃo à reversibilidade do processo foi observado que a quantidade adsorvida foi, em geral, o dobro da quantidade dessorvida quando da passagem de solvente puro sem mudanÃa da temperatura para todos os materiais estudados. Este fato demonstra que o carbono ativado nÃo possui uma boa regenerabilidade, ou seja, o carbono ativado retÃm parte do adsorbato mesmo apÃs a purga, o que acaba diminuindo a quantidade de sÃtios ativos do mesmo ao longo de ciclos sucessivos de adsorÃÃo/dessorÃÃo, embora se espere uma melhor recuperaÃÃo a temperaturas mais elevadas. O modelo de transporte dispersivo foi empregado para reproduzir o comportamento das curvas breakthrough e estimar parÃmetros de transferÃncia de massa, utilizando o solver comercial gPROMS. Assim, processos adsortivos para a remoÃÃo de componentes sulfurados a baixas concentraÃÃes podem ser uma alternativa viÃvel como complemento à unidades de hidrodessulfuraÃÃo (HDS). / In this study, modified carbonaceous materials were prepared by metals impregnation (copper, silver and palladium) for removing sulfur from synthetic solutions of benzothiophene in iso-octane solutions and also in commercial gasoline. Benzothiophene adsorption of iso-octane solutions (mixture model) was measured by fixed bed experiments filled with activated carbons with and without metal impregnation in three different temperatures: 30, 45 and 60ÂC. Breakthrough curves were simulated according to a mathematical model that considers operation nonlinear isothermal adsorption equilibrium, axial dispersion flow and mass transfer described by Linear Driving Force model (LDF). The LDF model for gas adsorption kinetics is frequently and successfully used for analysis of adsorption column dynamic data and for adsorptive process designs because it is simple, analytic, and physically consistent. The results confirmed the efficiency of activated carbons used in sulfur compounds adsorption, especially when its surface is modified with metals. Adsorption capacities, qm, were significant obtained for materials used, values in order of 1.08 mmol S/gads for GF45 activated carbon, 2.00 mmol S/gads for GF45/CuCl2 activated carbon, 2.38 mmol S/gads for GF45/AgCl activated carbon and 2.71 mmol S/gads to GF45/PdCl2 activated carbon to the mixture model and 0.14 mmol S/gads for GF45/AgCl activated carbon, 0.23 mmol S/gads to GF45 activated carbon, 0.30 mmol S/gads for GF45/CuCl2 activated carbon and 1.00 mmol S/gads for GF45/PdCl2 activated carbon, showing an improvement when working with materials impregnated with metals. In terms of selectivity, there was a better value for this parameter studies in material impregnated with palladium. With respect to process reversibility, it was observed that adsorption area was twice value of desorption area for all materials. This demonstrates that activated carbon has no good reversibility, ie, activated carbon retains part of adsorbate even after purging, which will ultimately decreasing the amount of same active sites over successive cycles of adsorption/desorption. Adsorptive processes for removing sulfur components can be a viable alternative to complement the HDS process.

No description available.