Banca de DEFESA: IURI CARDOSO SOARES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : IURI CARDOSO SOARES
DATA : 24/07/2019
HORA: 13:30
LOCAL: Pavilhão de Química - Sala 50
TÍTULO:

Synthesis and characterization of novel coordination compounds based on a pyrazole-substituted ligand

PALAVRAS-CHAVES:

coordination compounds, pyrazole, molecular magnetism, single-ion magnet, coordination polymer.

PÁGINAS: 120
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Campos de Coordenação
RESUMO:

In this work five new coordination compounds of the first row transition metals, a functionalized pyrazole ligand, KL, (5-amino-1-phenyl-1H-pyrazole-4-carboxylate) and one of the amines as auxiliary ligands: 2,2'-bipyridine (2,2'-bipy), 4,4'-bipyridine (4,4'-bipy) or 1,10'-phenanthroline (phen) were obtained.  Three reactional steps for the synthesis of the KL ligand were performed, which precursors were characterized by nfrared spectroscopy, melting point, 1 H-NMR and 13 C-NMR. The crystal structure of the precursor EL was obtained by x-ray diffraction. After the formation of the pre-ligand KL, an electrophilic susceptibility map was generated from DFT calculations, which evidenced the tendency of this ligand to coordinate in different ways, depending on stoichiometric, energetic and / or entropic factors. Based on this knowledge about the possible modes of coordination of KL, the synthesis of the coordination compounds was carried out using synthetic methods to reach them. A new family of coordination polymers with molecular formula 1∞ [M (L) 2 (4,4'-bipy) 2 (H 2 O) 2] n (M = CoII, NiII and CuII, ) (1-3), a polymer of 1 [CuII 2 (L) 2 (phen) 2] n (ClO 4) 2 (4) and a [CuII 2 (L) (2,2'-bipy) 4] dimer ClO4) 3 (5) were obtained. These compounds were characterized by elemental analysis, infrared spectroscopy and single-crystal x-ray diffraction. In addition compounds 3, 4 and 5 were studied by electronic paramagnetic resonance (EPR). The magnetic properties of compound 1 in the AC mode revealed slow relaxation of magnetization at low temperatures. The results showed that 1 behaves as a single-ion magnet, with a reversal barrier for 50 K.

MEMBROS DA BANCA:
Presidente - 102.827.717-27 - GUILHERME PEREIRA GUEDES - UFF
Externo ao Programa - 1560245 - ANTONIO GERSON BERNARDO DA CRUZ
Externo ao Programa - 1879496 - GUSTAVO BEZERRA DA SILVA
Externo à Instituição - ANTONIO DA SILVA FLORENCIO - IFRJ
Externo à Instituição - FABIO DA SILVA MIRANDA - UFF