No description available.

Made available in DSpace on 2015-05-14T13:21:52Z (GMT). No. of bitstreams: 1 parte1.pdf: 1989190 bytes, checksum: 883070176caa740fdfb17ea349bcf0ca (MD5) Previous issue date: 2010-12-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / We developed in this study the total synthesis of new potential ligands and / or chiral organocatalysts to be initially used in the Morita- Baylis-Hillman reaction and / or in other enantioselective reactions. The preparation of four new chiral unpublished compounds (31, 32, 33, 34) derivatives of pyridine and of R-(+)-camphor (21a) were performed. The chiral aldol adducts (31 and 32) were obtained by the reaction between 21a and aldehyde 35 or 36 in god chemical yields (80%-85%).The synthesis of 31 was done in 86% of diastereoisomeric excess. The new diois 33 and 34 were prepared from diastereoselective reduction of the corresponding aldol of 31 and 32 in high yield (88-90%) and 33 was prepared in de=77%. Determination of were performed from hydrogen NMR studies. We also present here, a toughly studies from spectroscopic techniques of 1H and 13C NMR, including COSY H,H; HETCOR and NOESY. The preliminary evaluation of 31 as organocatalysts was investigated from the Morita-Baylis-Hillman reaction between the methyl acrylate or acrylonitrile and p-nitrobenzaldehyde. This theory opens borders, for our group of researches, in the area of synthesis enantiosselective. / Desenvolvemos neste trabalho a síntese de novos ligantes e / ou organocatalisadores quirais em potenciais para serem inicialmente utilizados na reação de Morita-Baylis-Hillman e / ou em outras reações enantiosseletivas. As preparações dos quatro compostos quirais inéditos (31, 32, 33, 34) foram realizadas a partir dos aldeídos piridinicos comerciais derivados e da R-(+)-cânfora (21a). Os adutos quirais (31 e 32) foram obtidos pela reação entre 21a e o aldeído 35 ou 36 em bons rendimentos químicos (80%-85%). A síntese de 31 foi feita em 86% de excesso de diastereoisomérico. Os novos Dióis 33 e 34 foram preparados a partir da redução diastereosseletiva dos correspondentes aldóis 31 e 32, em altos rendimentos (88-90%) e 33 foi preparado em d.e. = 77%. A determinação dos excessos diastereoisoméricos foi feita a partir de estudos de RMN de hidrogênio. Apresentamos também aqui, estudos espectroscópicos de forma rigorosa, a partir de técnicas de espectroscopia de 1H e 13C, incluindo COSY H,H; HETCOR e NOESY. A avaliação preliminar de 31 como organocatalisador foi investigado através da reação de Morita-Baylis-Hillman entre o acrilato de metila ou acrilonitrila e o pnitrobenzaldeído. Esta tese abre fonteiras , para o nosso grupo de pesquisas, na área de síntese enantiosseletiva.

<p>Fully portable, rapid, and user-friendly sensors can successfully lead to the continuous monitoring of toxins present in the ecosystem as well as the detection of biomarkers to prevent diseases. Towards this goal, we explore electrochemical and colorimetric methods to develop platforms for the on-site detection of pesticides, heavy metals, and inflammation biomarkers. </p> <p>This thesis presents work with the primary aim of developing non-biological and biological-based platforms. Chapter 2 describes a fully roll-to-roll electrochemical sensor with high sensing and manufacturing reproducibility for detecting nitroaromatic organophosphorus pesticides (NOPPs). This sensor is based on a flexible, screen-printed silver electrode modified with a graphene nanoplatelets coating and a zirconia coating. This chapter outlines the evaluation of the electrocatalytic activity of zirconia towards the reduction of NOPPs, using methyl parathion as a pesticide sample. Furthermore, it describes the fundamentals of electrochemistry focused on voltammetry techniques used for surface characterization and quantification. The topics reviewed serve as the first step to further manufacturing sensors through large-scale methods (e.g., roll-to-roll). Chapter 3 describes the development of a dual-modality sensing system for the detection of mercury in river waters with high accuracy and precision. The objective of this project was to incorporate colorimetric platforms into the electrochemical methods to create a dual detection design and avert false positives and negatives. Here, novel bio-functional aptamers were incorporated in a sensor containing a paper test that detects mercury by a color change and an electrochemical test that measures charge transfer resistance changes upon aptamer-target interaction. For this platform, the colorimetric test demonstrates the utilization of two systems that consist of silver and gold citrate-capped nanoparticles bio-functionalized with highly specific aptamers. The mechanism of detection of these two systems is through Ps-AgNPs and Ps-AuNPs aggregation as a result of ssDNA-Hg2+ interaction. Using Ps-AuNPs microparticles, Chapter 4 describes a fully colorimetric and smartphone-based biosensor for detecting cardiac troponin T, a biomarker for diagnosing acute myocardial infarction. Here, a comparison in detection performance between Whatman grade 1 and high-flow filter paper is reviewed. Finally, Chapter 5 evaluates the colorimetric detection performance of Ps-AuNPs microparticles towards imidacloprid and carbendazim, two of the pesticides most found in imported produce in the United States. The chapter compares gold-based microparticles in which different aptamers were immobilized, and image acquisition approaches.</p> <p>All sensors reported in this thesis are especially suitable for environmental contaminants monitoring or point-of-care diagnosis applications. The materials selection, use or synthesis, and platforms’ performance optimization, development, and feasibility for scale-up manufacturing are expected to advance on-site biosensing technologies and their commercialization.</p>