Banca de QUALIFICAÇÃO: DIÊGO ULYSSES DE MELO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : DIÊGO ULYSSES DE MELO
DATA : 29/03/2023
HORA: 09:30
LOCAL: https://conferenciaweb.rnp.br/webconf/fernando-28
TÍTULO:

Chemiluminescence of a Firefly Luciferin Analog Reveals that Formation of the Key Intermediate Responsible for Excited-state Generation Occurs on a Fully concerted Step

PÁGINAS: 83
RESUMO:

The chemiluminescent (CL) reaction of eight different 2-(4-hydroxyphenyl)-4,5-dihydrothiazole-4-carboxylate esters with an organic superbase and oxygen, was investigated through a kinetic and computational study. These esters are all analogs to the luciferin substrate involved in efficient firefly bioluminescence. The kinetic data obtained from CL emission and light absorption assays were used in the context of linear-free energy relationships (LFER); we obtained the Hammett reaction constant ρ = +1.62 ± 0.09 and the Brønsted constant βlg = −0.36 ± 0.05. These observations from LFER, together with activation parameters obtained from Arrhenius plots, suggest that the formation of the high-energy intermediate (HEI) 1,2-dioxetanone occurs in a concerted mechanism during the rate-determining step of the reaction. Calculations performed using density functional theory support a late transition state for HEI formation.

 

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1939561 - FERNANDO HEERING BARTOLONI
Membro Titular - Examinador(a) Interno ao Programa - 1600860 - ALVARO TAKEO OMORI
Membro Titular - Examinador(a) Interno ao Programa - 1764199 - RODRIGO MAGHDISSIAN CORDEIRO
Membro Suplente - Examinador(a) Externo ao Programa - 1802150 - MARCO ANTONIO BUENO FILHO