Photoelectrochemical C-H Activation Through a Quinacridone Dye Enabling Proton-Coupled Electron Transfer.
ChemSusChem
; 16(5): e202201980, 2023 Mar 08.
Article
en En
| MEDLINE
| ID: mdl-36507568
ABSTRACT
Dye-sensitized photoanodes for C-H activation in organic substrates are assembled by vacuum sublimation of a commercially available quinacridone (QNC) dye in the form of nanosized rods onto fluorine-doped tin oxide (FTO), TiO2 , and SnO2 slides. The photoanodes display extended absorption in the visible range (450-600â
nm) and ultrafast photoinduced electron injection (<1â
ps, as revealed by transient absorption spectroscopy) of the QNC dye into the semiconductor. The proton-coupled electron-transfer reactivity of QNC is exploited for generating a nitrogen-based radical as its oxidized form, which is competent in C-H bond activation. The key reactivity parameter is the bond-dissociation free energy (BDFE) associated with the Nâ
/N-H couple in QNC of 80.5±2.3â
kcal mol-1 , which enables hydrogen atom abstraction from allylic or benzylic C-H moieties. A photoelectrochemical response is indeed observed for organic substrates characterized by C-H bonds with BDFE below the 80.5â
kcal mol-1 threshold, such as γ-terpinene, xanthene, or dihydroanthracene. This work provides a rational, mechanistically oriented route to the design of dye-sensitized photoelectrodes for selective organic transformations.
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Base de datos:
MEDLINE
Idioma:
En
Revista:
ChemSusChem
Asunto de la revista:
QUIMICA
/
TOXICOLOGIA
Año:
2023
Tipo del documento:
Article
País de afiliación:
Italia