On the mechanism of visible-light sensitized photosulfoxidation of toluidine blue O.
Photochem Photobiol
; 100(3): 772-781, 2024.
Article
em En
| MEDLINE
| ID: mdl-38100182
ABSTRACT
We report on the formation of toluidine blue O (TBO) sulfoxide by a self-sensitized photooxidation of TBO. Here, the photosulfoxidation process was studied by mass spectrometry (MS) and discussed in the context of photodemethylation processes which both contribute to TBO consumption over time. Analysis of solvent effects with D2O, H2O, and CH3CN along with product yields and MS fragmentation patterns provided mechanistic insight into TBO sulfoxide's formation. The formation of TBO sulfoxide is minor and detectable up to 12% after irradiation of 3 h. The photosulfoxidation process is dependent on oxygen wherein instead of a type II (singlet oxygen, 1O2) reaction, a type I reaction involving TBO to reach the TBO sulfoxide is consistent with the results. Density functional theory results point to the formation of the TBO sulfoxide by the oxidation of TBO via transiently formed peroxyl radical or thiadioxirane intermediates. We discover that the TBO photosulfoxidation arises competitively with TBO photodemethylation with the latter leading to formaldehyde formation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Photochem Photobiol
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Panamá
País de publicação:
Estados Unidos