Photoanodes for water oxidation with visible light based on a pentacyclic quinoid organic dye enabling proton-coupled electron transfer

2020 ◽  
Vol 56 (15) ◽  
pp. 2248-2251
Author(s):  
Giulia Alice Volpato ◽  
Martina Marasi ◽  
Thomas Gobbato ◽  
Francesca Valentini ◽  
Federica Sabuzi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Water Oxidation ◽  
Visible Region ◽  
Organic Dye ◽  
Proton Coupled Electron Transfer

A novel pentacyclic quinoid photosensitizer with extended absorption in the visible region and enabling proton-coupled electron transfer is employed in photoelectrodes for water oxidation in combination with a ruthenium polyoxometalate catalyst.

scholarly journals Light-Driven Depolymerization of Native Lignin Enabled by Proton- Coupled Electron Transfer

2019 ◽  
Author(s):  
Suong Nguyen ◽  
Phillip Murray ◽  
Robert Knowles
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Bond Cleavage ◽  
Direct Conversion ◽  
Alkoxy Radical ◽  
Radical Intermediate ◽  
Polymer Backbone ◽  
Good Efficiency ◽  
Chemical Reagents ◽  
Proton Coupled Electron Transfer

<div><p>Here we report a catalytic, light-driven method for the redox-neutral depolymerization of native lignin biomass at ambient temperature. This transformation proceeds via a proton-coupled electron-transfer (PCET) activation of an alcohol O–H bond to generate a key alkoxy radical intermediate, which then drives the <i>β</i>-scission of a vicinal C–C bond. Notably, this depolymerization is driven solely by visible light irradiation, requiring no stoichiometric chemical reagents and producing no stoichiometric waste. This method exhibits good efficiency and excellent selectivity for the activation and fragmentation of <i>β</i>-O-4 linkages in the polymer backbone, even in the presence of numerous other PCET-active functional groups. DFT analysis suggests that the key C–C bond cleavage reactions produce non-equilibrium product distributions, driven by excited-state redox events. These results provide further evidence that visible-light photocatalysis can serve as a viable method for the direct conversion of lignin biomass into valuable arene feedstocks.</p></div>

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 Atomically manipulated proton transfer energizes water oxidation on silicon carbide photoanodes

2018 ◽  
Vol 6 (47) ◽  
pp. 24358-24366 ◽  
Author(s):  
Hao Li ◽  
Huan Shang ◽  
Yuchen Shi ◽  
Rositsa Yakimova ◽  
Mikael Syväjärvi ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Electron Transfer ◽  
Proton Transfer ◽  
Water Oxidation ◽  
Proton Coupled Electron Transfer ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Preferential exposure of Si-face of SiC will mechanistically shift the rate limiting step of water oxidation from sluggish proton-coupled electron transfer on C-face to a more energy-favorable electron transfer.

Asymmetric alkylation of remote C(sp3)–H bonds by combining proton-coupled electron transfer with chiral Lewis acid catalysis

2017 ◽  
Vol 53 (64) ◽  
pp. 8964-8967 ◽  
Author(s):  
Wei Yuan ◽  
Zijun Zhou ◽  
Lei Gong ◽  
Eric Meggers
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom ◽  
Visible Light ◽  
Lewis Acid ◽  
Acid Catalysis ◽  
Hydrogen Atom Transfer ◽  
Lewis Acid Catalysis ◽  
Asymmetric Alkylation ◽  
Proton Coupled Electron Transfer ◽  
Chiral Lewis Acid

The catalytic asymmetric alkylation of the remote, unactivated δ-position of N-alkyl amides was enabled by the combination of visible-light-induced proton-coupled electron transfer, 1,5-hydrogen atom transfer, and chiral Lewis acid catalysis.

Aligning Electronic and Protonic Energy Levels of Proton-Coupled Electron Transfer in Water Oxidation on Aqueous TiO2

2014 ◽  
Vol 126 (45) ◽  
pp. 12242-12246 ◽  
Author(s):  
Jun Cheng ◽  
Xiandong Liu ◽  
John A. Kattirtzi ◽  
Joost VandeVondele ◽  
Michiel Sprik
Keyword(s):  
Electron Transfer ◽  
Water Oxidation ◽  
Energy Levels ◽  
Proton Coupled Electron Transfer

scholarly journals Frontispiece: Aligning Electronic and Protonic Energy Levels of Proton-Coupled Electron Transfer in Water Oxidation on Aqueous TiO2

2014 ◽  
Vol 53 (45) ◽  
pp. n/a-n/a
Author(s):  
Jun Cheng ◽  
Xiandong Liu ◽  
John A. Kattirtzi ◽  
Joost VandeVondele ◽  
Michiel Sprik
Keyword(s):  
Electron Transfer ◽  
Water Oxidation ◽  
Energy Levels ◽  
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.

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