Substituent Effects in the Photophysical and Electrochemical Properties of Meso-Tetraphenylporphyrin Derivatives.
Molecules
; 29(15)2024 Aug 04.
Article
en En
| MEDLINE
| ID: mdl-39125093
ABSTRACT
Porphyrins were identified some years ago as a promising, easily accessible, and tunable class of organic photoredox catalysts, but a systematic study on the effect of the electronic nature and of the position of the substituents on both the ground-state and the excited-state redox potentials of these compounds is still lacking. We prepared a set of known functionalized porphyrin derivatives containing different substituents either in one of the meso positions or at a ß-pyrrole carbon, and we determined their ground- and (singlet) excited-state redox potentials. We found that while the estimated singlet excited-state energies are essentially unaffected by the introduction of substituents, the redox potentials (both in the ground- and in the singlet excited-state) depend on the electron-withdrawing or electron-donating nature of the substituents. Thus, the presence of groups with electron-withdrawing resonance effects results in an enhancement of the reduction facility of the photocatalyst, both in the ground and in the excited state. We next prepared a second set of four previously unknown meso-substituted porphyrins, having a benzoyl group at different positions. The reduction facility of the porphyrin increases with the proximity of the substituent to the porphine core, reaching a maximum when the benzoyl substituent is introduced at a meso position.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Molecules
Asunto de la revista:
BIOLOGIA
Año:
2024
Tipo del documento:
Article
País de afiliación:
España
Pais de publicación:
Suiza