The Possible Role of Proton-Coupled Electron Transfer (PCET) in Water Oxidation by Photosystem II

ChemInform ◽  
2007 ◽  
Vol 38 (38) ◽  
Author(s):  
Thomas J. Meyer ◽  
My Hang V. Huynh ◽  
H. Holden Thorp
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Water Oxidation ◽  
Proton Coupled Electron Transfer

The role of proton coupled electron transfer in water oxidation

2012 ◽  
Vol 5 (7) ◽  
pp. 7704 ◽  
Author(s):  
Christopher J. Gagliardi ◽  
Aaron K. Vannucci ◽  
Javier J. Concepcion ◽  
Zuofeng Chen ◽  
Thomas J. Meyer
Keyword(s):  
Electron Transfer ◽  
Water Oxidation ◽  
Proton Coupled Electron Transfer

scholarly journals Design and synthesis of benzimidazole phenol-porphyrin dyads for the study of bioinspired photoinduced proton-coupled electron transfer

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1336-1345
Author(s):  
S. Jimena Mora ◽  
Daniel A. Heredia ◽  
Emmanuel Odella ◽  
Uma Vrudhula ◽  
Devens Gust ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Photosystem Ii ◽  
Proton Transfer ◽  
Water Oxidation ◽  
Oxidation Catalyst ◽  
Design And Synthesis ◽  
Proton Coupled Electron Transfer ◽  
Anchoring Groups ◽  
High Redox Potential

Benzimidazole phenol-porphyrin dyads have been synthesized to study proton-coupled electron transfer (PCET) reactions induced by photoexcitation. High-potential porphyrins have been chosen to model P680, the photoactive chlorophyll cluster of photosynthetic photosystem II (PSII). They have either two or three pentafluorophenyl groups at the meso positions to impart the high redox potential. The benzimidazole phenol (BIP) moiety models the Tyr[Formula: see text]-His190 pair of PSII, which is a redox mediator that shuttles electrons from the water oxidation catalyst to P680[Formula: see text]. The dyads consisting of a porphyrin and an unsubstituted BIP are designed to study one-electron one-proton transfer (E1PT) processes upon excitation of the porphyrin. When the BIP moiety is substituted with proton-accepting groups such as imines, one-electron two-proton transfer (E2PT) processes are expected to take place upon oxidation of the phenol by the excited state of the porphyrin. The bis-pentafluorophenyl porphyrins linked to BIPs provide platforms for introducing a variety of electron-accepting moieties and/or anchoring groups to attach semiconductor nanoparticles to the macrocycle. The triads thus formed will serve to study the PCET process involving the BIPs when the oxidation of the phenol is achieved by the photochemically produced radical cation of the porphyrin.

scholarly journals The mechanism for proton–coupled electron transfer from tyrosine in a model complex and comparisons with Y Z oxidation in photosystem II

2002 ◽  
Vol 357 (1426) ◽  
pp. 1471-1479 ◽  
Author(s):  
Martin Sjödin ◽  
Stenbjörn Styring ◽  
Björn Åkermark ◽  
Licheng Sun ◽  
Leif Hammarström
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Water Oxidation ◽  
Oxidation Mechanism ◽  
Model System ◽  
Proton Coupled Electron Transfer ◽  
Tyrosine Oxidation ◽  
Model Complex ◽  
Primary Donor ◽  
Mn Cluster

In the water–oxidizing reactions of photosystem II (PSII), a tyrosine residue plays a key part as an intermediate electron–transfer reactant between the primary donor chlorophylls (the pigment P 680 ) and the water–oxidizing Mn cluster. The tyrosine is deprotonated upon oxidation, and the coupling between the proton reaction and electron transfer is of great mechanistic importance for the understanding of the water–oxidation mechanism. Within a programme on artificial photosynthesis, we have made and studied the proton–coupled tyrosine oxidation in a model system and been able to draw mechanistic conclusions that we use to interpret the analogous reactions in PSII.

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