pH-Dependent Reduction Potentials and Proton-Coupled Electron Transfer Mechanisms in Hydrogen-Producing Nickel Molecular Electrocatalysts

2013 ◽  
Vol 52 (7) ◽  
pp. 3643-3652 ◽  
Author(s):  
Samantha Horvath ◽  
Laura E. Fernandez ◽  
Aaron M. Appel ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Electron Transfer ◽  
Reduction Potentials ◽  
Proton Coupled Electron Transfer ◽  
Ph Dependent ◽  
Transfer Mechanisms

THEORETICAL STUDIES ON THE COUPLING INTERACTIONS AND SELF-EXCHANGE REACTION MECHANISMS IN THE COMPLEXES OF NO WITH ONH AND NOH

2008 ◽  
Vol 07 (03) ◽  
pp. 435-446 ◽  
Author(s):  
PING LI ◽  
XIAOYAN XIE ◽  
YUXIANG BU ◽  
WEIHUA WANG ◽  
NANA WANG ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Exchange Reaction ◽  
Reaction Mechanisms ◽  
Natural Bond Orbital ◽  
Theoretical Studies ◽  
Exchange Reactions ◽  
Electron Transfer Mechanism ◽  
Proton Coupled Electron Transfer ◽  
Planar Geometries ◽  
Transfer Mechanisms

The coupling interactions and self-exchange reaction mechanisms between NO and ONH (NOH) have been systematically investigated at the B3LYP/6-311++G** level of theory. All the equilibrium complexes are characterized by the intermolecular H-bonds and co-planar geometries. The cisoid NOH/ON species is the most stable one among all the complexes considered due to the formation of an N – N bond. Moreover, all the cisoid complexes are found to be more stable than the corresponding transoid ones. The origin of the blueshifts occurring in the selected complexes has been explored, employing the natural bond orbital (NBO) calculations. Additionally, the proton transfer mechanisms for the self-exchange reactions have been proposed, i.e. they can proceed via the three-center proton-coupled electron transfer or five-center cyclic proton-coupled electron transfer mechanism.

Atmospheric formation of the NO3 radical from gas-phase reaction of HNO3 acid with the NH2 radical: proton-coupled electron-transfer versus hydrogen atom transfer mechanisms

2014 ◽  
Vol 16 (36) ◽  
pp. 19437-19445 ◽  
Author(s):  
Josep M. Anglada ◽  
Santiago Olivella ◽  
Albert Solé
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Phase Reaction ◽  
Electron Transfer Mechanism ◽  
Proton Coupled Electron Transfer ◽  
No3 Radical ◽  
Transfer Mechanisms ◽  
Atmospheric Formation

The amidogen radical abstracts the hydrogen from nitric acid through a proton coupled electron transfer mechanism rather than by an hydrogen atom transfer process.

Probing electron transfer between hemin and riboflavin using a combination of analytical approaches and theoretical calculations

2017 ◽  
Vol 19 (48) ◽  
pp. 32580-32588 ◽  
Author(s):  
Wen-Lan Wang ◽  
Yuan Min ◽  
Sheng-Song Yu ◽  
Wei Chen ◽  
Jie-Jie Chen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Theoretical Calculations ◽  
Resonance Method ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic Resonance Method ◽  
Proton Coupled Electron Transfer ◽  
Analytical Approaches ◽  
Electron Paramagnetic ◽  
Transfer Mechanisms

Proton-coupled electron transfer mechanisms of riboflavin bound hemin in aqueous solution are elucidated by spectroelectrochemical analysis, the electron paramagnetic resonance method and theoretical calculations.

Blended hydrogen atom abstraction and proton-coupled electron transfer mechanisms of closed-shell molecules

2012 ◽  
Vol 3 (6) ◽  
pp. 1903 ◽  
Author(s):  
Chunsen Li ◽  
David Danovich ◽  
Sason Shaik
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom ◽  
Closed Shell ◽  
Hydrogen Atom Abstraction ◽  
Proton Coupled Electron Transfer ◽  
Transfer Mechanisms

pH-Dependent metal-based redox couples as models for proton-coupled electron transfer reactions

1998 ◽  
Vol 174 (1) ◽  
pp. 391-416 ◽  
Author(s):  
Spencer J. Slattery ◽  
Jean K. Blaho ◽  
Joseph Lehnes ◽  
Kenneth A. Goldsby
Keyword(s):  
Electron Transfer ◽  
Transfer Reactions ◽  
Electron Transfer Reactions ◽  
Proton Coupled Electron Transfer ◽  
Redox Couples ◽  
Ph Dependent

Phenolic betalain as antioxidants: meta means more

2020 ◽  
Vol 92 (2) ◽  
pp. 243-253 ◽  
Author(s):  
Letícia C. P. Gonçalves ◽  
Nathana B. Lopes ◽  
Felipe A. Augusto ◽  
Renan M. Pioli ◽  
Caroline O. Machado ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom Transfer ◽  
Antioxidant Potential ◽  
Human Consumption ◽  
Ph Effects ◽  
Radical Chain ◽  
Proton Coupled Electron Transfer ◽  
Chain Breaking ◽  
The Relationship ◽  
Transfer Mechanisms

AbstractBetalains are phytochemicals of nutraceutical importance that emerged as potent antioxidants, preventing radical chain propagation and the deleterious health effects of oxidative stress. However, despite the wide application of betalains as color additives in products for human consumption, little is known about the relationship between their structure and antioxidant potential. Here we investigate the mechanism of antioxidant action of three regioisomeric phenolic betalains and show that the meta isomer has higher antiradical capacity than most natural betalains, anthocyanins and flavonoids. Structural and pH effects on redox and antiradical properties were investigated and the results are rationalized in light of quantum chemical calculations. Our results demonstrate that hydrogen atom transfer/proton-coupled electron transfer or sequential proton loss electron transfer mechanisms are plausible to explain the radical chain breaking properties of phenolic betalains in water. Furthermore, mesomeric effects are responsible for the stabilization of the resulting radical phenolic betalains. These findings are useful for the design of biocompatible antioxidants and for the development of novel additives for functional foods and cosmetics with high antioxidant potential.

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