Banca de QUALIFICAÇÃO: JOSE ANTONIO DE SOUSA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: JOSE ANTONIO DE SOUSA
DATA: 25/07/2025
HORA: 14:30
LOCAL: Auditório do PPGQ - UFPI
TÍTULO: Electronic and Steric Influence of Olefinic Monomers on the [RuCl₂(PPh₃)₂(piperidine)] Complex in Polymerization Reactions.
PALAVRAS-CHAVES: Metathesis, polymer synthesis, metal-carbene complex
PÁGINAS: 13
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
RESUMO:

ROMP is an important means of obtaining functionalized polymeric macromolecules with the possibility of retaining unsaturation. In this perspective, four different monomers (norbornene-NBE (M1), NBE(COOH) 2 (M2), NBE(COOCH 3 ) 2 (M3) and NBE(COOCH 2 CH 3 ) 2 (M4)) were applied to the complex [RuCl 2 (PPh 3 ) 2 (piperidine)] with the aim of verifying the electronic and steric effects caused by reactions via metathesis to obtain a catalyst suitable for polymerization. The interaction energy between the C=C double bond of the monomers with ruthenium showed an apparent reduction following the order of increasing chain in the monomers. This reduction is almost accompanied by an increase in steric hindrance. Of the reaction pathways proposed for the formation of complex 8 ([RuCl 2 (pip)(EDA)m], m=M1, M2, M3 or M4), fundamental to ROMP and polymer formation, it was identified that the pathway that proposes an initial coordination of EDA with subsequent coordination of the monomers is the most viable. The lowest energy barrier for the first proposed transition state, TS 1 , was identified when the M3 monomer is applied. For the second state, TS 2 , the lowest energy barrier was found when M1 is used. The results also indicate that the interaction between ruthenium and oxygen from EDA or monomers is decisive in the spontaneity of the occurrence of reactions, in which, when the metal is in greater geometric proximity to the oxygen of the
double bond (–C=O), the formation of complexes becomes more favourable.

MEMBROS DA BANCA:
Presidente - 1714193 - JOSE MILTON ELIAS DE MATOS
Interno - 778.***.***-91 - FRANCISCO DAS CHAGAS ALVES LIMA - UESPI
Interno - 1508806 - WELTER CANTANHEDE DA SILVA
Externo ao Programa - 004.***.***-93 - JOSÉ LUIZ SILVA SÁ - USP
Externo à Instituição - 941.***.***-20 - ATAUALPA ALBERT CARMO BRAGA - USP