Banca de DEFESA: BEATRIZ AZEVEDO GALVÃO DE LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : BEATRIZ AZEVEDO GALVÃO DE LIMA
DATE: 18/03/2022
TIME: 14:00
LOCAL: videoconferência
TITLE:

Development of phenanthroline complexes of manganese, cobalt and zinc with kojic acid: synthesis, spectroscopic and electrochemical study

KEY WORDS:

Bioinorganic. Cobalt complexes. Manganese complexes. Zinc complexes. Kojic acid.

PAGES: 106
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Campos de Coordenação
SUMMARY:

The use of metals in pharmaceutical formulations in the treatment and diagnosis of diseases is something old, however, it was from the discovery of the antitumor properties of cisplatin that the eyes of the scientific community were opened to the application of metal complexes as chemotherapeutics in the treatment of cancer. The later discovery of the toxicity of cisplatin implied the search for new coordination compounds, aiming at similar efficacy allied to a low toxicity. In this context, manganese, cobalt and zinc complexes stand out in the literature as promising in the treatment of cancer, both for their low toxicity and for their magnetic and electrochemical properties. Therefore, this work presents, with the objective of contributing to the inorganic chemistry of Mn (II), Co (II) and Zn (II) systems, the synthesis and spectroscopic and electrochemical characterization of new complexes with phenanthroline and kojic acid of the type [M(phen)(koj)₂], where M = Mn (II), Co(II) and Zn(II), phen corresponds to 1,10-phenanthroline and Hkoj to 5-hydroxy-2- (hydroxymethyl)-4H-pyran-4-one (kojic acid). All complexes were synthesized by adding the ligand Hkoj to the precursor complexes [M(phen)Cl₂], with M = Mn (II), Co (II) and Zn (II), in a 1:2 ratio of precursor to ligand, using water as a solvent in the presence of potassium hydroxide. The compounds were characterized by vibrational spectroscopy in the infrared region (IR), electron absorption spectroscopy in the UV and visible region (UV-Vis) and cyclic voltammetry (CV). Analyzing the vibrational spectra obtained in KBr pellets, in the systems [M(phen)(koj)₂] there is the presence of phenanthroline bands in the complexes near the region 1427, 844 and 727 cm^-1, in addition to the ligand bands kojic acid, with stretch values at 1630, 1611, 1581, 877 and 548 cm^-1. The electronic spectra of the [M(phen)(koj)₂] complexes obtained in aqueous media showed intraligand bands in the ultraviolet region, which refer to electronic transitions of phenanthroline with absorption at approximately 222, 268 and 291 nm, in addition to the band around 320 nm referring to the kojic ion (koj^-). While d-d bands were observed only for the Co and Mn (II) complexes. Cyclic voltammograms of Hkoj and the final complexes of Co and Mn (II) were obtained in KCl 0.1 mol.L^-1, pH= 7.0, showing almost reversible processes for both metals. For cobalt there is the Co³⁺/Co²⁺ process and for manganese Mn³⁺/Mn²⁺, in addition to the irreversible oxidation process of the Hkoj ligand.

BANKING MEMBERS:
Interno - 1086214 - ANDERSON DOS REIS ALBUQUERQUE
Externo ao Programa - 1715109 - DANIEL DE LIMA PONTES
Externo ao Programa - 1945343 - FRANCISCO ORDELEI NASCIMENTO DA SILVA
Presidente - 2413537 - POLLYANA SOUZA CASTRO
Externa à Instituição - WENDY MARINA TOSCANO QUEIROZ DE MEDEIROS - IFBA