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Abstract(s)
O principal objetivo desta tese foi o desenvolvimento de sensores seletivos para a deteção de analitos distintos nomeadamente, metais tóxicos, compostos nitroaromáticos percursores de explosivos e nitroanilinas.
O trabalho experimental envolveu a síntese de sistemas conjugados poliméricos e não poliméricos baseados em calix[4]arenos bicíclicos integrando unidades sinalizadoras de carbazole possuindo padrões de substituição distintos, resultando macromoléculas fluorescentes tanto em solução como no estado sólido.
A preparação destes novos materiais compreendeu a síntese e caracterização dos monómeros de partida e dos seus percursores. Os sistemas conjugados foram sintetizados pela reação de acoplamento cruzado de Sonogashira-Hagihara e caracterizados por Ressonância Magnética Nuclear de Protão (RMN H1), Espetroscopia de Infravermelho de Transformada de Fourier (FTIR) e Cromatografia de Permeação em Gel (GPC).
As suas propriedades fotofísicas foram estudadas por espetroscopia de absorção de estado fundamental (UV-Vis) e de fluorescência de estado estacionário, exibindo os sistemas sintetizados bons rendimentos quânticos de fluorescência assim como elevada estabilidade sob condições de irradiação contínua.
A capacidade de deteção dos sistemas conjugados foi avaliada em solução para os metais tóxicos revelando seletividade e sensibilidade no reconhecimento de cobre. Os materiais foram também testados como sensores químicos em solução e no estado sólido na deteção de nitroanilinas isoméricas (orto-, meta- e para-nitroanilina) e de nitroaromáticos explosivos, nomeadamente, 2,4,6-trinitrotolueno e ácido pícrico.
Utilizando a fluorescência de estado estacionário como técnica de deteção, os estudos mostraram que os filmes obtidos são seletivos para a deteção de orto-nitroanilina em detrimento dos outros isómeros. A análise de Stern-Volmer dos ensaios em solução evidenciou para os materiais estudados uma sensibilidade diferenciada para a deteção de nitroanilinas em comparação com compostos nitroaromáticos explosivos, destacando-se uma maior seletividade para orto-nitroanilina.
A capacidade de complexação de alguns materiais com o cobre e a orto-nitroanilina foi avaliada por fluorescência aplicando o método de variações contínuas, revelando estequiometrias de complexação diferenciadas para os diferentes pares analisados.
The main goal of this thesis was the development of selective sensors for the detection of distinct analytes namely toxic metals, nitroaromatic compounds precursors of explosives and nitroanilines. The experimental work involved the synthesis of polymeric and non-polymeric bicyclic calix[4]arene-based conjugated systems, integrating carbazole segments as fluorescent signaling moieties with distinguished carbazole linkages, resulting in fluorescent macromolecules in both liquid phase and solid state. The preparation of this new materials involved the synthesis and characterization of starting monomers and its precursors. The conjugated systems were synthesized by Sonogashira-Hagihara cross-coupling reaction and characterized by Proton Nuclear Magnetic Resonance (1H NMR), Fourier-Transform Infrared spectroscopy (FTIR) and Gel Permeation Chromatography (GPC). Their photophysical properties were studied by ground state absorption (UV-Vis) and steady-state fluorescence spectroscopy, exhibiting the synthetized systems high quantum yields of fluorescence and great stability toward photobleaching. The sensing ability of conjugated polymers was evaluated toward toxic metals in fluid phase, showing selectivity and sensibility for copper recognition. The materials were also tested as fluid phase and solid-state fluorescent chemical sensors for the detection of isomeric nitroanilines (ortho-, meta- e para-nitroaniline) and nitroaromatic explosives, namely, 2,4,6-trinitrotoluene and picric acid. Using steady-state fluorescence as the detection technique, experiments have shown that obtained films are selective for o-nitroaniline towards the other isomers. A Stern-Volmer analysis of solution essays showed a differentiated sensitivity of the materials for the detection of nitroanilines compared to explosive nitroaromatic compounds, with a higher selectivity for ortho-nitroaniline. The complexing ability of some materials with copper and ortho-nitroaniline was evaluated by fluorescence applying the method of continuous variations, revealing differentiate complexing stoichiometry for the different analyzed pairs.
The main goal of this thesis was the development of selective sensors for the detection of distinct analytes namely toxic metals, nitroaromatic compounds precursors of explosives and nitroanilines. The experimental work involved the synthesis of polymeric and non-polymeric bicyclic calix[4]arene-based conjugated systems, integrating carbazole segments as fluorescent signaling moieties with distinguished carbazole linkages, resulting in fluorescent macromolecules in both liquid phase and solid state. The preparation of this new materials involved the synthesis and characterization of starting monomers and its precursors. The conjugated systems were synthesized by Sonogashira-Hagihara cross-coupling reaction and characterized by Proton Nuclear Magnetic Resonance (1H NMR), Fourier-Transform Infrared spectroscopy (FTIR) and Gel Permeation Chromatography (GPC). Their photophysical properties were studied by ground state absorption (UV-Vis) and steady-state fluorescence spectroscopy, exhibiting the synthetized systems high quantum yields of fluorescence and great stability toward photobleaching. The sensing ability of conjugated polymers was evaluated toward toxic metals in fluid phase, showing selectivity and sensibility for copper recognition. The materials were also tested as fluid phase and solid-state fluorescent chemical sensors for the detection of isomeric nitroanilines (ortho-, meta- e para-nitroaniline) and nitroaromatic explosives, namely, 2,4,6-trinitrotoluene and picric acid. Using steady-state fluorescence as the detection technique, experiments have shown that obtained films are selective for o-nitroaniline towards the other isomers. A Stern-Volmer analysis of solution essays showed a differentiated sensitivity of the materials for the detection of nitroanilines compared to explosive nitroaromatic compounds, with a higher selectivity for ortho-nitroaniline. The complexing ability of some materials with copper and ortho-nitroaniline was evaluated by fluorescence applying the method of continuous variations, revealing differentiate complexing stoichiometry for the different analyzed pairs.
Description
Trabalho final de mestrado para obtenção do grau de mestre em Engenharia Química e Biológica
Keywords
Calixarenos Calixarenes Carbazole Carbazole Polímeros Polymers Metais tóxicos Toxic metals Explosivos Explosives Nitroanilinas Nitroanilines Sensores Sensors
Citation
FIALHO, Carina Bento - Sensores fluorescentes na deteção de poluentes. Lisboa: Instituto Superior de Engenharia de Lisboa, 2018. Dissertação de mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa