Spin‐regulated Electron Transfer and Exchange‐enhanced Reactivity in Fe4S4‐mediated Redox Reaction of the Dph2 Enzyme During the Biosynthesis of Diphthamide

2021 ◽  
Author(s):  
Jianqiang Feng ◽  
Sason Shaik ◽  
Binju Wang
Keyword(s):  
Electron Transfer ◽  
Redox Reaction

scholarly journals Photoredox Reaction of trans-4-Stilbenecarboxylatopentaamminecobalt(III)

1979 ◽  
Vol 34 (2) ◽  
pp. 271-274 ◽  
Author(s):  
Arnd Vogler ◽  
Alfred Kern
Keyword(s):  
Electron Transfer ◽  
Chemical Reaction ◽  
Oxidation Product ◽  
Redox Reaction ◽  
Excited Singlet ◽  
Low Complex

AbstractThe irradiation (λ = 313 nm) of aqueous [Co(III)(NH3)5TSC]2+(TSC-= trans-4-stilbenecarboxylate) leads to a redox reaction with formation of Co2+ as has been shown previously. The TSC-ligand is oxidized to the radical in the primary photoreaction. At higher complex concentrations (～10-2 M) this TSC radical is oxidized to stable products (Φ = 0.09 ± 0.02) by [Co(NH3)5TSC]2+,which is reduced to Co2+ leading to release of the TSC- ligand (Φ = 0.07 ± 0.02). Co2+ is thus formed by both the secondary and the primary photo chemical reaction (Φ overall = 0.16). At low complex concentrations (< 10-4 M) in the presence of air, the primary TSC radical is scavenged by O2. Benz-aldehyde is an oxidation product. This reduces the formation of Co2+ to Φ = 0.09 ± 0.02, which is taken to be the efficiency of the primary photo chemical step. It is suggested that the photoredox reaction is initiated by an electron transfer from the first excited singlet of the TSC- ligand. As shown by sensitization experiments, the population of the lowest TSC-triplet leads to the usual trans/cis isomerization of the TSC-ligand, but not to the redox reaction.

scholarly journals Electrodeposition behaviour of copper from ore leachate and copper ammonium sulphate

2020 ◽  
Vol 55 (3) ◽  
pp. 229-236
Author(s):  
AI Ambo ◽  
HJ Glassa ◽  
C Peng
Keyword(s):  
Electron Transfer ◽  
Ammonium Sulphate ◽  
Redox Reaction ◽  
Chemical Reduction ◽  
Metallic Copper ◽  
Electron Transfer Reaction ◽  
Single Electron ◽  
Electrochemical Kinetics ◽  
Electron Transfer Processes ◽  
Copper Ammonium

The deposition behaviour of copper ammonia complexes from ore leachate and synthetic copper ammonium sulphate solutions was investigated using cyclic voltammetrywith platinumas counter electrode. The work is carried out to understand the deposition behaviour of the ore for hydrometallurgical and electro winning application. The chemical reduction and deposition of copper from both solutions consisted of two reversible electrochemical processes, each involving the transfer of a single electron. The Cu(NH3)4 2+ complex in the copper leachate is first reduced to Cu(NH3)4 + before being reduced to metallic copper. With synthetic copper ammonium sulphate (Cu(NH3)4SO4), the reduction to metallic copper is a ligand-coupled electron transfer reaction which proceeds as two sequential, single-electron transfer processes. The Cu/Cu(NH3)4 2+ redox reaction during deposition of copper from the leachate is fast compared to that of the Cu/Cu2+ redox reaction in the Cu(NH3)4SO4 synthetic solution. Investigation of the electrochemical kinetics shows that the linear relationship between the peak current and the square root of the scan rate is an indication that the Cu(NH3)4 + and Cu(NH3)4SO4 reduction to Cu proceeds through a diffusion-controlled process. Bangladesh J. Sci. Ind. Res.55(3), 229-236, 2020

Studies of Reactions between Flavins and Quinones, Mercaptans, and Enolates

1972 ◽  
Vol 27 (9) ◽  
pp. 1016-1020 ◽  
Author(s):  
Morton J. Gibian ◽  
D. Lauriston Elliott ◽  
Charles Kelly ◽  
Brad Borge ◽  
Kirklen Kupecz
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Redox Reaction ◽  
Radical Anion ◽  
Second Order ◽  
Ph Values ◽  
Order Rate

A. Equilibrium and second-order rate constants have been measured for the redox reaction between phthaloquinone and dihydroriboflavin (and its reverse) at a number of pH values. The equilibria and kinetic determinations are in agreement. No intermediates could be found in the reaction, and it is proposed that with this and other quinones electron transfer occurs within a complex of the flavin and hydroquinone (or dihydroflavin and quinone). B. A survey of the reaction between mercaptans and flavins is reported, as well as data showing that with mercaptoethanol the reaction is reversible, the disulfide and reduced flavin giving mercaptan and flavin. C. The reaction of alkylphenone enolates with isoalloxazine is described. This reaction leads t 50% isoalloxazine radical anion and an adduct of the enolate with the ketone. A possible route for this process is discussed.

Photoinduced electron transfer across a water–oil boundary as a model for redox reaction separation

Nature ◽  
1979 ◽  
Vol 280 (5725) ◽  
pp. 823-824 ◽  
Author(s):  
ITAMAR WILLNER ◽  
WILLIAM E. FORD ◽  
JOHN W. OTVOS ◽  
MELVIN CALVIN
Keyword(s):  
Electron Transfer ◽  
Redox Reaction ◽  
Photoinduced Electron Transfer
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