Development of chemosensors for ions based on quinoxaline and quercetine derivatives
The development of artificial sensors for detecting ionic analytes in solution has attracted much attention, mainly to the biological and environmental areas, due to the possibility of rapid and high sensitivity analysis through simple and low-cost procedures. In the present work, syntheses of ne...
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| Formato: | doctoralThesis |
| Idioma: | pt_BR |
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Brasil
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/28878 |
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| Resumo: | The development of artificial sensors for detecting ionic analytes in solution has attracted much
attention, mainly to the biological and environmental areas, due to the possibility of rapid and
high sensitivity analysis through simple and low-cost procedures. In the present work, syntheses
of new quinoxaline derivatives were performed aiming to the detection of ions in aqueous
solution. A total of nine derivatives compounds were obtained in good yields (65-84%) by a
one-pot type procedure. The process begins with the oxidation of L-ascorbic acid, followed by
reaction with two equivalents of o-phenylenediamine, to generate the AAQX compound which
is converted to the final products via formation of a Schiff base from reaction with aromatic
aldehydes. Nine compounds were synthesized and two were tested as chemosensors. It has been
found that the final product obtained from benzaldehyde (N-(2-((Z)-
benzylidene)amino)phenyl)-3-((1S,2S)-1,2,3-trihydroxypropyl)quinoxaline-2-carboxiamide)
proved to be a selective chromogenic chemosensor for Cu2+ over the other cations in methanolwater solution 20%. The compound obtained from p-nitrobenzaldehyde (N-(2-((Z)-(4-
nitrobenzylidene)amino)phenyl)-3-((1S,2S)-1,2,3-trihydroxypropyl)quinoxaline-2-
carboxamide), was effective in detecting Fions in DMSO and DMSO-water solution (2.5%).
The mechanism of action for these chemosensors has been proposed based on theoretical and
spectroscopic data. Finally, a multidisciplinary proposal for chemistry lectures based on the
capacity of a complex formed by Al3+ and quercetin natural product (QCT) for the detection of
F
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anions in an aqueous medium is presented. The proposal begins with the easy isolation of
Rutin from the root of the Bredemeyera floribunda Willd plant, followed by a synthetic
proposal for hydrolysis of the isolated substance, obtaining then quercetin. From quercetin was
obtained a complex with Al3+ in a 2:1 stoichiometry (QCT: Al3+) that was characterized and
applied as a chemosensor for Fby colorimetric, UV-visible and fluorescence tests. The
multidisciplinary character of this project involves the areas of natural products, synthesis,
complex chemistry, and theoretical calculations, and is, therefore, able to provide relevant
stimuli for the chemistry student in their undergraduate courses. |
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