Analysis of Hydrogen-Bonding Effects on Excited-State Proton-Coupled Electron Transfer from a Series of Phenols to a Re(I) Polypyridyl Complex

2017 ◽  
Vol 121 (23) ◽  
pp. 12569-12576 ◽  
Author(s):  
Prateek Dongare ◽  
Annabell G. Bonn ◽  
Somnath Maji ◽  
Leif Hammarström
Keyword(s):  
Electron Transfer ◽  
Hydrogen Bonding ◽  
Excited State ◽  
Polypyridyl Complex ◽  
Proton Coupled Electron Transfer

Proton-coupled electron transfer from a luminescent excited state

2008 ◽  
pp. 4267 ◽  
Author(s):  
Jonathan C. Freys ◽  
Gérald Bernardinelli ◽  
Oliver S. Wenger
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
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 Visualizing the protons in a metalloenzyme electron proton transfer pathway

2020 ◽  
Vol 117 (12) ◽  
pp. 6484-6490 ◽  
Author(s):  
Hanna Kwon ◽  
Jaswir Basran ◽  
Juliette M. Devos ◽  
Reynier Suardíaz ◽  
Marc W. van der Kamp ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Transfer ◽  
Hydrogen Bonding ◽  
Proton Transfer ◽  
Proton Donor ◽  
Biological Processes ◽  
Proton Coupled Electron Transfer ◽  
Neutron Structure ◽  
Bona Fide ◽  
Electron Proton Transfer

In redox metalloenzymes, the process of electron transfer often involves the concerted movement of a proton. These processes are referred to as proton-coupled electron transfer, and they underpin a wide variety of biological processes, including respiration, energy conversion, photosynthesis, and metalloenzyme catalysis. The mechanisms of proton delivery are incompletely understood, in part due to an absence of information on exact proton locations and hydrogen bonding structures in a bona fide metalloenzyme proton pathway. Here, we present a 2.1-Å neutron crystal structure of the complex formed between a redox metalloenzyme (ascorbate peroxidase) and its reducing substrate (ascorbate). In the neutron structure of the complex, the protonation states of the electron/proton donor (ascorbate) and all of the residues involved in the electron/proton transfer pathway are directly observed. This information sheds light on possible proton movements during heme-catalyzed oxygen activation, as well as on ascorbate oxidation.

scholarly journals Excited-state proton-coupled electron transfer within ion pairs

2020 ◽  
Vol 11 (13) ◽  
pp. 3460-3473 ◽  
Author(s):  
Wesley B. Swords ◽  
Gerald J. Meyer ◽  
Leif Hammarström
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Ion Pairs ◽  
Proton Coupled Electron Transfer ◽  
General Method ◽  
Salicylate Ion

Electrostatic ion pairs provide a general method to study excited-state proton-coupled electron transfer. A PTaETb mechanism is identified for the ES-PCET oxidation of salicylate within photoexcited cationic ruthenium–salicylate ion pairs.

scholarly journals Excited state structural dynamics of 4-cyano-4′-hydroxystilbene: deciphering the signatures of proton-coupled electron transfer using ultrafast Raman loss spectroscopy

2019 ◽  
Vol 21 (40) ◽  
pp. 22409-22419 ◽  
Author(s):  
Reshma Mathew ◽  
Surajit Kayal ◽  
Adithya Lakshmanna Yapamanu
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Structural Dynamics ◽  
Transfer Process ◽  
Electron Transfer Process ◽  
Proton Coupled Electron Transfer

The photo-initiated proton-coupled electron transfer process in the 4-cyano-4′-hydroxystilbene–tert-butylamine adduct strongly affects the excited-state structural dynamics of CHSB.

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