Banca de QUALIFICAÇÃO: VITOR FERREIRA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : VITOR FERREIRA DA SILVA
DATE: 05/11/2024
TIME: 14:00
LOCAL: videoconferência
TITLE:

PHOTOCHEMICAL STUDY, ACIDOCHROMISM, AND INTERACTION WITH METAL CATIONS OF 2-(4-(DECYLOXY)PHENYL)-1H-IMIDAZO[4,5-f]PHENANTHROLINE

KEY WORDS:

N-Heterocycles; Imidazophenanthroline; Fluorescence; Acidochromism; Chemosensors

PAGES: 70
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Fotoquímica Orgânica
SUMMARY:

The study of fluorescent organic materials has gained significant relevance due to their important applications in various fields. Within this context, the exploration of structures containing aromatic N-heterocyclic cores stands out, being particularly interesting for the study of acidichromism, which has important implications in the field of sensors. The present work reports a study on the photochemical and acidichromic properties of the compound 2-(4-(decyloxy)phenyl)-1H-imidazo[4,5-f]phenanthroline (1), which was synthesized with yields ranging from 50-65% through two multicomponent protocols. The photochemistry of compound 1 was studied in hexane, dichloromethane (DCM), tetrahydrofuran (THF), acetonitrile (ACN), dimethyl sulfoxide (DMSO), and methanol (MeOH), with maximum absorption wavelengths observed between 307-317 nm, indicating the absence of pronounced solvatochromism. On the other hand, the fluorescent capacity of the imidazophenanthroline derivative varied considerably depending on the solvent, with higher emissions observed in THF (λEM = 430 nm) and DMSO (λEM = 450 nm), and a quantum yield of up to 31% in the former solvent. In other solvents, either the emissions were low, or the material was characterized as non-emissive. The effect of water addition on the emissive behavior of compound 1 in polar solvents was investigated. In MeOH, a slight enhancement in emission was observed with fw = 20%, likely due to the aggregation effect. In ACN, the addition of water led to a drastic reduction in emission starting from the initial water additions. In THF, water addition up to fw = 20% resulted in a slight reduction in emission, which remained high in intensity and red-shifted (λEM = 450 nm). Based on the results obtained in THF-H2O, the acidochromism of compound 1 in the presence of HCl was evaluated, characterized by the decrease in the emission band at λEM = 450 nm until complete extinction of fluorescence. Additionally, the effect of adding aqueous NaOH was also evaluated, initially resulting in a decrease and slight red-shift of the emission band (λEM = 467 nm), until complete suppression of fluorescence at higher base concentrations. Currently, interactions of compound 1 with gallic acid derivatives and metal cations are being evaluated, aiming at the development of supramolecular systems of technological interest and in the sensor´s field.

COMMITTEE MEMBERS:
Presidente - 1803692 - FABRICIO GAVA MENEZES
Interno - 1198847 - JOSE LUIS CARDOZO FONSECA
Externo à Instituição - ANDRÉ HERCULANO DE OLIVEIRA - UFRN