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Cápsulas de Coordenação Auto-Montadas para Encapsulação e Deteção de Poluentes Farmacêuticos
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A contaminação das águas é um problema recorrente. Vários estudos demonstram
que diferentes contaminantes, como os antibióticos e anti-inflamatórios, ficam presentes
na água, mesmo após esta ter passado pelos diversos processos de tratamento das
Estações de Tratamento de Águas Residuais (ETAR). Pela grande importância que a água
tem para todos os seres vivos que habitam a Terra e o seu difícil acesso, é indispensável
usá-la e reutilizá-la da melhor maneira possível. Com o intuito de detetar, quantificar e
eliminar os contaminantes com mais eficácia, têm vindo a ser feitos estudos com cápsulas
de coordenação auto-montadas. Neste trabalho foi sintetizada uma cápsula previamente
descrita por Fujita onde 6 metais de Paládio (II) e 4 ligandos orgânicos formam uma
estrutura octaédrica com uma cavidade no seu interior.
Partiu-se de PdCl2 e N,N,N',N’-Tetrametiletilenodiamina (tmeda), obtendo-se o
precursor de paládio pretendido, Pd(tmeda)(NO3)2 (2). Para a síntese do ligando, Tris(4-
Piridil)-s-Triazina, (Py3T) (3) reagiu-se 4-cianopiridina com hidróxido de sódio (NaOH).
A cápsula de coordenação Pd6L4 pode ser obtida diretamente através da reação dos
reagentes 2 e 3 em água. Investigou-se o potencial desta cápsula para formar complexos
de inclusão com diversos corantes.
Com base na supressão de fluorescência observada mediante a encapsulação do
fluoróforo, desenvolveu-se um sensor supramolecular para a deteção de fármacos
baseado num mecanismo de complexação competitiva. Este mecanismo baseia-se na
substituição do corante pelo analito no interior da cápsula e consequente regeneração do
sinal de fluorescência após libertação do primeiro no seio da solução. Explorou-se o
mecanismo para testar a encapsulação de vários poluentes farmacêuticos, tais como
ibuprofeno, naproxeno e penicilina. Foram feitas titulações por espetroscopia de
ultravioleta-visível, fluorescência e ressonância magnética nuclear confirmando-se a
encapsulação do ibuprofeno pelo sensor supramolecular, com os corantes fluoresceína,
eosina Y ou eritrosina B.
Water contamination has been a recurring problem. Several reports show contaminants, such as antibiotics and anti-inflammatories, still being in the water that has been through the numerous processes in a Wastewater Treatment Plant. Being the water a very important resource for all the living creatures on Earth, and its increasingly difficult accessibility, it is essential to use and reuse it in the best possible manner. In order to detect, quantify and eliminate the contaminants efficiently, there have been studies with self-assembled coordination cages. In this project a cage previously synthetized by Fujita, in which 6 Palladium (II) molecules bind to 4 organic ligands to form an octahedral structure with a hollow cavity inside, will be evaluated as a potential supramolecular sensor. The synthesis started from PdCl2 and N,N,N',N’-Tetramethylethylenediamine (tmeda), obtaining the desired molecule, Pd(tmeda)(NO3)2 (2). To synthetize the ligand, Tris(4-Pyridil)-s-Triazine, (Py3T) (3), 4-cyanopyridine reacted with sodium hydroxide (NaOH). The coordination cage Pd6L4, can be obtained reacting 2 and 3 in water. The potential of this cage was studied to form inclusion complexes with different dyes. Since there is fluorescence suppression when the fluorophore is encapsulated, a supramolecular sensor was developed to detect pharmaceutical compounds based on a competitive complexation mechanism. This mechanism is explained by the exchange between the dye and the analyte inside the cage and therefore regenerating the fluorescence signal after the release of the dye on the solution. It was used to explore the encapsulation of different pharmaceutical pollutants such as ibuprofen, naproxen and penicillin. Titrations were performed on ultraviolet-visible, fluorescence spectroscopy and nuclear magnetic resonance confirming the encapsulation of ibuprofen by the supramolecular sensor with fluorescein, eosin Y and erythrosin B dyes.
Water contamination has been a recurring problem. Several reports show contaminants, such as antibiotics and anti-inflammatories, still being in the water that has been through the numerous processes in a Wastewater Treatment Plant. Being the water a very important resource for all the living creatures on Earth, and its increasingly difficult accessibility, it is essential to use and reuse it in the best possible manner. In order to detect, quantify and eliminate the contaminants efficiently, there have been studies with self-assembled coordination cages. In this project a cage previously synthetized by Fujita, in which 6 Palladium (II) molecules bind to 4 organic ligands to form an octahedral structure with a hollow cavity inside, will be evaluated as a potential supramolecular sensor. The synthesis started from PdCl2 and N,N,N',N’-Tetramethylethylenediamine (tmeda), obtaining the desired molecule, Pd(tmeda)(NO3)2 (2). To synthetize the ligand, Tris(4-Pyridil)-s-Triazine, (Py3T) (3), 4-cyanopyridine reacted with sodium hydroxide (NaOH). The coordination cage Pd6L4, can be obtained reacting 2 and 3 in water. The potential of this cage was studied to form inclusion complexes with different dyes. Since there is fluorescence suppression when the fluorophore is encapsulated, a supramolecular sensor was developed to detect pharmaceutical compounds based on a competitive complexation mechanism. This mechanism is explained by the exchange between the dye and the analyte inside the cage and therefore regenerating the fluorescence signal after the release of the dye on the solution. It was used to explore the encapsulation of different pharmaceutical pollutants such as ibuprofen, naproxen and penicillin. Titrations were performed on ultraviolet-visible, fluorescence spectroscopy and nuclear magnetic resonance confirming the encapsulation of ibuprofen by the supramolecular sensor with fluorescein, eosin Y and erythrosin B dyes.
Descrição
Palavras-chave
Contaminação das Águas Cápsulas de Coordenação Automontagem Sensor Supramolecular Poluentes Farmacêuticos