Banca de DEFESA: KATHERINE LIMA BRUNO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : KATHERINE LIMA BRUNO
DATE: 04/08/2022
TIME: 09:00
LOCAL: videoconferência
TITLE:

Spectroscopic and electrochemical study of new mono and binuclear complexes of Cu(II) and Fe(II) with nitrogenous ligands.

KEY WORDS:

Copper complexes; iron complexes; nitrogen ligands.

PAGES: 116
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Química Bio-Inorgânica
SUMMARY:

In an attempt to develop more efficient compounds for pharmacological treatments, bioinorganic chemistry has been playing important roles with the participation of coordination compounds. Among these, copper(II) and iron(II) complexes stand out, which play important roles in biological systems, naturally – as in enzymes and proteins – or artificially – as pharmacological agents. Using these metals associated with molecules that already have biological activity described in the literature, such as phenanthroline, piperazine and nitrite, it becomes possible to develop drugs with greater potential, due not only to the diverse structural possibility, but to the wide spectrum of biochemical applications. . In this sense, this work aims to contribute to bioinorganic chemistry with the synthesis and characterization of new mono compounds - [Cu(phen)(pip)NO2]Cl and Na2[Fe(CN)4(NH3)2] - and binuclear – Na[(NO2)(phen)Cu–pip–Fe(CN)4(NH3)] – of copper(II) and iron(II), where phen = 1,10- phenanthroline and pip = piperazine. The mononuclear copper complex was obtained through the reaction, in methanol, between its precursor – [Cu(phen)Cl2] – and the ligands piperazine and nitrite; the iron compound, in water, through the reaction between its precursor – Na2[Fe(CN)4(DMSO)2] – and ammonia gas, with subsequent precipitation (NaI); and the binuclear, from the addition of the two monomers in methanol and water, all of which are characterized by spectroscopic (IV and UV-Vis) and electrochemical (cyclic voltammetry) techniques. By means of IV and Uv-vis, it was possible to verify the main vibrational modes of phenanthroline and piperazine in the synthesized copper systems, through the C=C (1580, 1517, 1492 and 1427 cm-1) stretching of the rings and N-H (1615 cm-1) of the amine, as well as intense bands with transitions π→π* (204, 221, 272 and 293 nm) and n→π* (204 nm) in the ultraviolet region, respectively, in addition to the d-d bands (625 and 692 nm) of Cu2+  in the visible region. The nitrite stretches were also evidenced in the IR with the signs at 1349(a) and 1269(s) cm-1. For iron systems, it was possible to identify their main stretches (νN-H, νC≡N, δFe-CN), through the IV, and their bands in the UV-vis, such as the MLCT charge transfer (dπ Fe2+ → pπ * CN- at 221 nm) and d-d (405 and 518 nm) of Fe2+. The cyclic voltammograms allowed the visualization of a quasi-reversible system for the 3 complexes, with only one redox process each, referring to the pair Cu2+/1+ and Fe2+/1+ and the overlap of these two in the binuclear, in addition to the observation of greater stability and evaluation of the nature of the ligands.

COMMITTEE MEMBERS:
Externo ao Programa - 1715109 - DANIEL DE LIMA PONTES - nullPresidente - 349770 - DULCE MARIA DE ARAUJO MELO
Externo ao Programa - 1945343 - FRANCISCO ORDELEI NASCIMENTO DA SILVA - nullExterna à Instituição - WENDY MARINA TOSCANO QUEIROZ DE MEDEIROS - IFRN