Banca de QUALIFICAÇÃO: THUANNY MOURA DE SOUSA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : THUANNY MOURA DE SOUSA
DATA : 14/12/2018
HORA: 14:00
LOCAL: Sala 3H9
TÍTULO:

DEVELOPMENT AND REACTIVITY OF A NEW RUTHENIUM NITROSYL COMPLEX WITH POSSIBLE ANTIBACTERIAL ACTION

PALAVRAS-CHAVES:

Nitrosyl complexes. Ruthenium. Pseudomonas aeruginosa.

PÁGINAS: 92
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Campos de Coordenação
RESUMO:

The present work aims at the development of nitrosyl ruthenium complexes capable of acting as a donor of nitric oxide in biological systems, since this molecule acts in a variety of physiological processes such as such as neurotransmission, blood pressure regulation and participation in the capacity of the immune system to destroy tumor cells and intracellular parasites. For this reason, we present the synthesis, characterization, reactivity and antibacterial assays of the cis-[Ru(bpy)(phen)(TU) (NO)](PF₆)₃ complex where TU = thiourea, bpy = 2.2 '-bipyridine and phen = 1,10'-phenanthroline. Complex nitrosyl was obtained in acetone by continuous bubbling of NO⁺_(g) from the thiourea and cis-[Ru(bpy)(phen)Cl₂] precursor complex. By means of the UV-Vis technique it was possible to identify the charge transfer bands of the metal for the polypyridine ligands in the values of 330 and 409 nm in water and methanol, respectively, as for the nitrosyl ligand at 450-500 nm range. As regards the infrared spectrum, the asymmetric and symmetric ѵ(NH₂) values at 3411 and 3126 cm^-1 indicated coordination of the thiourea ligand as well as the existence of a band at 1113 cm^-1 referring to ѵ(C-N) indicated the thiourea via the sulfur atom. In addition, bands in the range of 1600 to 1450 cm-1 were observed for ѵ(C=C) and ѵ(C=N) of polypyridine ligands as well as a band in 1926 cm -1 referring to ѵ(NO⁺) indicating coordination of nitric oxide in its linear form. Analyzing the cyclic voltammogram in NaTFA 0,1 mol/ L and pH 3,5, a nearly reversible process was observed at 37.5 mV for the NO^+/0 redox pair. Regarding the reactivity study, the complex showed the capability to release nitric oxide by photochemical reduction and that the nitrosyl nitrite interconversion reaction occurs at pH 6,70. When verifying the labilization of nitric oxide by square-wave voltammetry it was suggested that its release occurs through a chemical reaction, in which, by reducing the NO⁺ bond to NO⁰, it is released due to weak Ru-NO⁰ interaction coordinating in its place a molecule of water. In addition, the antibacterial activity of the nitrosyl complex was investigated against the bacteria Pseudomonas aeruginosa ATCC-9027. The test revealed a MIC in the value of 121.5 μM indicating that the compound under study has the capacity to inhibit the growth of these bacteria.

MEMBROS DA BANCA:
Presidente - 1945343 - FRANCISCO ORDELEI NASCIMENTO DA SILVA
Externo ao Programa - 1530500 - ANA CRISTINA FACUNDO DE BRITO PONTES
Externo ao Programa - 1715109 - DANIEL DE LIMA PONTES