Banca de QUALIFICAÇÃO: ALEXSANDRO LIMA DOS ANJOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : ALEXSANDRO LIMA DOS ANJOS
DATA : 24/11/2017
HORA: 14:00
LOCAL: Sala 3G1
TÍTULO:

SYNTHESIS AND CHARACTERIZATION OF MOLYBDENUM (VI) COMPLEXES WITH NITROGENATED LIGANDS

PALAVRAS-CHAVES:

Molybdenum; Phenanthroline; Azide; Nitrogenated Ligands

PÁGINAS: 80
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Campos de Coordenação
RESUMO:

Molybdenum is a metal that is present in the human body and performs various functions, such as assisting catalytic processes of oxy-reduction and transfer of oxygen atoms between various substrates. In addition, complexes with this metal are widely used as precursors to obtain new compounds with enhanced activities and as catalysts in epoxidation reactions. Thus, the present work aims at the synthesis and characterization of complexes of molybdenum (VI) in its cis-dioxo isomer with ligands 1,10-Phenantroline (phen), Azide (N₃­^-) and Metformin (met). Thus, the cis-[Mo(phen)(O)₂Cl₂], cis- [Mo(phen)(O)₂(N₃)₂] and cis- [Mo(met)(O)₂Cl₂] compounds were obtained from the precursor cis-[Mo(DMSO)₂(O)₂ Cl₂]. The compounds were obtained based on methodologies described in the literature and by adaptation of procedures of synthesis of structurally similar complexes. The characterization was performed using spectroscopic techniques (Infrared and Uv-vis) and electrochemical techniques. Based on the analysis of the vibrational spectra it was possible to verify the presence of the characteristic absorptions for compounds containing the oxide ligands, the Mo=O stretch. Bands at 919 and 891 cm^-1 for the precursor, 933 and 896 cm^-1 for complex with the ligand phen, 915 and 885 cm^-1 for azido-complex and 947 and 891 cm^-1 for complex with metformin, in addition to variation in the main absorptions of the other ligands, showing coordination with the metal. The electronic spectra, obtained in water, did not present d-d transitions, since molybdenum is in its maximum oxidation state (6+). Only the intraligand bands for DMSO at 213 nm were verified, in addition to the ligand-metal charge transfer bands (LMCT) at 234 nm for the chloride ligand and 272 nm for the DMSO. The complexes containing the phenanthroline ligand presented characteristic intraligand bands for the system, whereas the metformin complex showed two intraligand transitions at 209 and 229 nm. The analysis by Cyclic Voltammetry presented to the compounds an irreversible process corresponding to the Mo⁵⁺ / Mo⁶⁺ redox couple.

MEMBROS DA BANCA:
Externo ao Programa - 1715109 - DANIEL DE LIMA PONTES
Externo ao Programa - 1804952 - FERNANDO JOSE VOLPI EUSEBIO DE OLIVEIRA
Interno - 1945343 - FRANCISCO ORDELEI NASCIMENTO DA SILVA