Artículo
Mimicking the electron transfer chain in photosystem II with a molecular triad thermodynamically capable of water oxidation
Megiatto, Jackson D.; Antoniuk Pablant, Antaeres; Sherman, Benjamin D.; Kodis, Gerdenis; Gervaldo, Miguel Andres
; Moore, Thomas A.; Moore, Ana L.; Gust, Devens
![Icon](/themes/CONICETDigital/images/conicet.png)
Fecha de publicación:
03/2012
Editorial:
National Academy of Sciences
Revista:
Proceedings of the National Academy of Sciences of The United States of America
ISSN:
0027-8424
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
In the photosynthetic photosystem II, electrons are transferred from the manganese-containing oxygen evolving complex (OEC) to the oxidized primary electron-donor chlorophyll P680•+ by a proton-coupled electron transfer process involving a tyrosine-histidine pair. Proton transfer from the tyrosine phenolic group to a histidine nitrogen positions the redox potential of the tyrosine between those of P680•+ and the OEC. We report the synthesis and time-resolved spectroscopic study of a molecular triad that models this electron transfer. The triad consists of a high-potential porphyrin bearing two pentafluorophenyl groups (PF10), a tetracyanoporphyrin electron acceptor (TCNP), and a benzimidazole-phenol secondary electron-donor (Bi-PhOH). Excitation of PF10 in benzonitrile is followed by singlet energy transfer to TCNP (τ = 41 ps), whose excited state decays by photoinduced electron transfer (τ = 830 ps) to yield Bi-PhOH-PF 10•+-TCNP•-. A second electron transfer reaction follows (τ < 12 ps), giving a final state postulated as BiH+-PhO•-PF10-TCNP•-, in which the phenolic proton now resides on benzimidazole. This final state decays with a time constant of 3.8 μs. The triad thus functionally mimics the electron transfers involving the tyrosine-histidine pair in PSII. The final charge-separated state is thermodynamically capable of water oxidation, and its long lifetime suggests the possibility of coupling systems such as this system to water oxidation catalysts for use in artificial photosynthetic fuel production.
Palabras clave:
BIOMIMICRY
,
PHOTOCHEMISTRY
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CCT - CORDOBA)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CORDOBA
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CORDOBA
Citación
Megiatto, Jackson D.; Antoniuk Pablant, Antaeres; Sherman, Benjamin D.; Kodis, Gerdenis; Gervaldo, Miguel Andres; et al.; Mimicking the electron transfer chain in photosystem II with a molecular triad thermodynamically capable of water oxidation; National Academy of Sciences; Proceedings of the National Academy of Sciences of The United States of America; 109; 39; 3-2012; 15578-15583
Compartir
Altmétricas