Theoretical Analysis of the Sequential Proton-Coupled Electron Transfer Mechanisms for H2 Oxidation and Production Pathways Catalyzed by Nickel Molecular Electrocatalysts

2012 ◽  
Vol 116 (4) ◽  
pp. 3171-3180 ◽  
Author(s):  
Laura E. Fernandez ◽  
Samantha Horvath ◽  
Sharon Hammes-Schiffer

2012 ◽  
Vol 109 (39) ◽  
pp. 15663-15668 ◽  
Author(s):  
S. Horvath ◽  
L. E. Fernandez ◽  
A. V. Soudackov ◽  
S. Hammes-Schiffer


2008 ◽  
Vol 07 (03) ◽  
pp. 435-446 ◽  
Author(s):  
PING LI ◽  
XIAOYAN XIE ◽  
YUXIANG BU ◽  
WEIHUA WANG ◽  
NANA WANG ◽  
...  

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.



2014 ◽  
Vol 16 (36) ◽  
pp. 19437-19445 ◽  
Author(s):  
Josep M. Anglada ◽  
Santiago Olivella ◽  
Albert Solé

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





2017 ◽  
Vol 19 (48) ◽  
pp. 32580-32588 ◽  
Author(s):  
Wen-Lan Wang ◽  
Yuan Min ◽  
Sheng-Song Yu ◽  
Wei Chen ◽  
Jie-Jie Chen ◽  
...  

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.





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 ◽  
...  

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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