Banca de DEFESA: LILIAN CAVALCANTE DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LILIAN CAVALCANTE DA SILVA
DATE: 10/02/2020
TIME: 09:30
LOCAL: auditório do Química III
TITLE:

DEVELOPMENT OF CHEMOSENSORS FOR IONS BASED ON QUINOXALINE AND QUERCETINE DERIVATIVES

KEY WORDS:

Chemosensors; cations; anions; quinoxaline; quercetin

PAGES: 120
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Síntese Orgânica
SUMMARY:

The development of artificial chemosensors for detection of ionic analytes has attracted great attention to biological and environmental fields due the possibility of fast and sensitive analysis via simple and low cost procedures. This work reports the synthesis, structural elucidation and evaluation of some quinoxaline and quercetin derivatives to detect ions in solution. Firstly, synthesis and characterization of nine novel polyfunctionalized quinoxaline potentially applied as chemosensors is presented. These compounds were obtained in good yilds (65-84%) via an one-pot procedure starting from oxidation of L-ascorbic acid followed by its reaction with two equivalents of o-phenylenediamine to afford the compound AAQX. This later reacts with aromatic aldehydes to provide a series of Schiff base as final products. Two compounds were selected to be evaluated as chemosensors. The product from reaction with benzaldehyde was verified as a selective chromogenic chemosensor for Cu²⁺ toward several pother cations in methanol-water 4:1 v/v. On the other hand, a nitrated compound was verified effect for detection of F^- in DMSO and DMSO-water. Sensing mechanisms were proposed based in spectroscopic and theoretical data. In the second part, a multidisciplinary proposal for chemistry classes is presented. This approach is based in the ability of a coordination complex between quercetin and Al³⁺ to detect F^- in aqueous medium. Initially, rutin is easily isolated from Bredemeyera floribunda Willd and then undergoes hydrolysis fo afford quercetin. Alternatively, rutin can be purchase at interesting price. A 2:1 coordination complex between quercetin and Al³⁺ (QCT₂-Al³⁺) was characterized and applied as chromogenic and fluorogenic sensor for detection of F^-. This project showed to be very interesting since it encompasses several areas, such as natural products, synthesis, organometallic chemistry and computational chemistry, leading to high stimulus for undergraduate students in chemistry courses. Lastly, a review article based on quinoxaline derivative as chromogenic and fluorogenic chemosensors for cation in solution is proposed.

BANKING MEMBERS:
Presidente - 1803692 - FABRICIO GAVA MENEZES
Interno - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS
Interna - 1805556 - LUCIENE DA SILVA SANTOS
Externo à Instituição - RODRIGO CRISTIANO - UFPB
Externo à Instituição - SAVIO MOITA PINHEIRO - UFPB