Banca de QUALIFICAÇÃO: TAMIRES ALVES DO NASCIMENTO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : TAMIRES ALVES DO NASCIMENTO
DATE: 09/12/2021
TIME: 14:00
LOCAL: google meet
TITLE:

CONTRIBUTIONS OF MOLECULAR ELECTROCHEMISTRY IN MEDICINAL CHEMISTRY AND IN THE ANALYSIS OF FLUORESCENT PROBES

KEY WORDS:

Organic Electrochemistry; Hybrid Quinones; BODIPY derivatives; Cyclic Voltammetry; Electrodic Mechanisms

PAGES: 67
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Físico-Química Orgânica
SUMMARY:

Molecular electrochemistry is useful for characterizing redox reactions and deciphering reactional mechanisms associated with electron transfer. Quinones represent a wide and varied family of metabolites of natural distribution. The interest in these substances has increased due to their contribution to vital biochemical processes and increasing prominence for their biological and pharmacological activities. Despite the various beneficial effects, quinones are also considered toxins. It is precisely this double behavior (pro-oxidant versus antioxidant) that gives this class of compounds a peculiarity of great interest to researchers, especially in medicinal chemistry. Fluorescent compounds are attractive substrates and have been widely used as chemical sensors, laser dyes, and therapeutic applications, and their electrochemical properties are adjustable. Substitution at different positions affects the electronic environment around the BODIPY core, causing characteristic changes in oxidation and reduction potentials and other physical-chemical properties. Both quinones and BODIPYS are promising bioactive molecules that have stood out as prototype candidates for drugs or probes. This work investigated the electrochemical behavior in electrochemical cells, in vitro hybrid quinones and nitrosyl-BODIPYs, in an aprotic medium ((ACN or DMF + TBAPF₆ 0.1 mol L^-1) to obtain data on their redox mechanisms, electrogenerated intermediates, formation of reactive oxygen species, and interaction with biological macromolecules. The electrochemical techniques used were cyclic voltammetry and differential pulse voltammetry on vitreous carbon electrodes (d = 3 mm). The counter electrode was a platinum wire, and the reference electrode, Ag | AgCl, Cl− (saturated). We investigated 14 acrylated quinones, and in the comparison among reduction potentials and biological activities, it was noted that the most electrophilic (more positive reduction potentials) presented the highest trypanocidal activity (CI₅₀/24 h, less than about 300 μM), except for one of them. An apparent correlation between the presence of an electron-withdrawing group, such as chlorine, with an easier reduction and a higher biological activity, appeared, together with an ideal range for the reduction potential. In the aprotic medium employed, all compounds, with first wave reduction potential values (Ep1c), around -0.5 V or more positive, were active. These compounds can be considered "highly oxidizing" in this biological context, with consequences on trypanocidal activity. Nitrosylated BODIPYs were investigated at α (5-nitrosyl) and β (6-nitrosyl). The location of the NO group on α or β strongly affects the electronic structures and redox behavior. The electrochemical spectrum associated with Conceptual Density analysis and Functional Theory (CDFT) corroborates the voltammetric results and explains the unexpected reactivity differences. The nitrosyl group is the first to be reduced in 5-nitrosyl-BODIPY, while in the beta isomer, the nitrosyl group strongly facilitates the reduction in the BODIPY moiety.

BANKING MEMBERS:
Presidente - 2120103 - MARILIA OLIVEIRA FONSECA GOULART
Interno - 1119939 - ANTONIO EUZEBIO GOULART SANTANA
Interna - 1247925 - ANIELLE CHRISTINE ALMEIDA SILVA
Externa ao Programa - 1320545 - THAISSA LUCIO SILVA
Externa ao Programa - 1105255 - JERUSA MARIA DE OLIVEIRA AMORIM
Externa à Instituição - ANA CAROLINE FERREIRA SANTOS - UFAL
Externa à Instituição - ANDRESA KATHERINNE ALBUQUERQUE DE ALMEIDA - UFAL