Banca de DEFESA: LEONARDO MARTINS CARNEIRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LEONARDO MARTINS CARNEIRO
DATE: 20/12/2022
TIME: 13:00
LOCAL: https://conferenciaweb.rnp.br/webconf/fernando-28
TITLE:

Experimental and Theoretical Study Regarding the Deactivation Mechanisms of the Excited-states, Solvatochromism, and Interaction with Ions of Fluorescent Aryl-aryl-nitrones

PAGES: 116
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Fotoquímica Orgânica
SUMMARY:

In the search for fluorophores that possess multi-channels of deactivation, it is common to design molecules that can act through different photophysical mechanisms, such as the excited-state intramolecular proton transfer (ESIPT), twisted intramolecular charge transfer (TICT) or aggregation-induced emission (AIE). For each one of these mechanisms there are established structural conditions that should be observed for its occurrence. The molecule α-(2-hydroxyphenyl)-N-phenyl nitrone (Nit-OH) has these required structural attributes, however, due to the known instability of nitrone derivatives under exposure to UV-Vis light, the properties of this compound and its derivatives has remained unexplored so far. This work, through experimental and computational data, sought to characterize the photophysical mechanisms present in the first (S₁) and second (S₂) singlet electronic excited states of Nit-OH, in acetonitrile, hexane, and ethanol as solvents. It was identified the occurrence of the ESIPT process in both S₁ and S₂ states, and of the TICT process in the S₁, followed by a conical intersection, which can be avoided by dimer formation through AIE. A study of the effect of the substituent in the para position according to the hydroxyl group was also carried out, using the nitro, chlorine, and methyl groups. In this study, the steric effect of the chloro and methyl substituents was evident, preventing the formation of aggregates, while the nitro group remains planar in the excited state and favors aggregation. Finally, the compound Nit-OH was applied as a metal ion sensor in acetonitrile solution, which showed great selectivity for copper (II) ions with a limit of detection of 3.03 µM.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1939561 - FERNANDO HEERING BARTOLONI
Membro Titular - Examinador(a) Interno ao Programa - 312.257.708-90 - YURI ALEXANDRE AOTO - NENHUMA
Membro Titular - Examinador(a) Externo ao Programa - 1768959 - FERNANDO CARLOS GIACOMELLI
Membro Suplente - Examinador(a) Externo ao Programa - 1309493 - PEDRO ALVES DA SILVA AUTRETO
Membro Suplente - Examinador(a) Externo à Instituição - TIAGO ARAUJO MATIAS - UFU