Banca de DEFESA: ANDRÉIA BOARO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ANDRÉIA BOARO
DATA : 15/12/2021
HORA: 13:00
LOCAL: meet.google.com/hkg-qnmt-pgz
TÍTULO:

Mechanistic study of the induced decomposition of lophine-derived hydroperoxides and silylperoxides and synthesis of fluorescent arginine derivatives for labeling antimicrobial peptides

PÁGINAS: 241
RESUMO:

A kinetic study of the chemiluminescent (CL) reaction mechanism of lophine-derived hydroperoxides and silylperoxides, induced by base and fluoride, respectively, provided evidence for the formation of a 1,2-dioxetane as high-energy intermediate (HEI) of this CL transformation. This was postulated using a linear Hammett relationship consistent with the formation of negative charge on the transition state of HEI generation (ρ > 1). The decomposition of this HEI leads to chemiexcitation with overall low singlet excited state formation quantum yield (Φ_S); nonetheless, Φ_S = 1.20 × 10^–3 E mol^–1 was observed with both peroxides substituted with bromine. The use of electron-donating substituents increases chemiexcitation efficiency, while it also reduces the rate for both formation and decomposition of the HEI. Different possible pathways for HEI decomposition and chemiexcitation are discussed in light of literature data, from the perspective of the substituent effect. This system could be explored in the future for analytical and labelling purposes, or for biological oxidation through chemiexcitation. Furthermore, five fluorescent arginine derivatives were prepared, purified, and characterized successfully. However, the synthesized fluorescent arginine derivatives could not be coupled to an antimicrobial peptide due to the lack of a protecting group. Nonetheless, a valuable understanding of reactivity and issues associated with the protection of arginine derivatives has been obtained. This will be valuable for future projects on this topic.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1939561 - FERNANDO HEERING BARTOLONI
Membro Titular - Examinador(a) Interno ao Programa - 1909951 - ARTUR FRANZ KEPPLER
Membro Titular - Examinador(a) Interno ao Programa - 1544344 - VANI XAVIER DE OLIVEIRA JUNIOR
Membro Titular - Examinador(a) Externo à Instituição - THIAGO CARITA CORRERA - USP
Membro Titular - Examinador(a) Externo à Instituição - JOSEF WILHELM BAADER - USP
Membro Suplente - Examinador(a) Interno ao Programa - 3050857 - CELIO FERNANDO FIGUEIREDO ANGOLINI
Membro Suplente - Examinador(a) Externo ao Programa - 2249395 - THIAGO BRANQUINHO DE QUEIROZ
Membro Suplente - Examinador(a) Externo à Instituição - ALESSANDRO RODRIGUES - UNIFESP