Banca de QUALIFICAÇÃO: KATHERINE LIMA BRUNO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : KATHERINE LIMA BRUNO
DATE: 04/04/2022
TIME: 14:00
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 new structures that are more efficient in medicinal treatments, coordination compounds have been playing very important roles in bioinorganic chemistry. Among these, the most abundant transition metal compounds in the body, such as copper(II) and iron(II), play fundamental roles in biological systems, naturally - as in enzymes and proteins - or artificial – as pharmacological agents. Using these trace elements associated with bioactive molecules that already have activities in the treatment of numerous pathologies, 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 - [Cu(phen)(pip)NO2]Cl and Na2[Fe(CN)4(NH3)2] - and binuclear compounds – Na[(NO2)(phen)Cu–pip–Fe(CN)4(NH3)] – of copper(II) and iron(II), in which phen = 1,10-phenanthroline, pip = piperazine, NO2- = nitrite, CN = cyanide and NH3 = ammonia. The mononuclear copper complex was obtained through its reaction, in methanol, between its precursor – [Cu(phen)Cl2] – and the ligands piperazine and nitrite; iron complex, in water, through the reaction between its precursor – Na2[Fe(CN)4(DMSO)2] – and ammonia gas, with subsequent precipitation; and binuclear, from the addition of the two monomers in methanol and water, all of which are characterized by spectroscopic (infrared and UV-vis) and electrochemical (cyclic voltammetry) techniques. By means of IR and UV-vis spectroscopy, it was possible to verify the main vibrational modes of phenanthroline and piperazine in the synthesized copper systems, through the C=C stretching of the rings and N-H of the amine, as well as intense bands with π→π* and n→ π* transitions in the ultraviolet region, respectively, in addition to the Cu2+ d-d bands 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-) and d-d 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 Fe3+/2+ and the superposition of these two in the binuclear, in addition to the observation of greater stability and evaluation of the nature of the ligands.

BANKING MEMBERS:
Presidente - 349770 - DULCE MARIA DE ARAUJO MELO
Externo ao Programa - 1715109 - DANIEL DE LIMA PONTES
Externo ao Programa - 1945343 - FRANCISCO ORDELEI NASCIMENTO DA SILVA