scholarly journals KOtBu as a Single Electron Donor? Revisiting the Halogenation of Alkanes with CBr4 and CCl4

Molecules ◽  
2018 ◽  
Vol 23 (5) ◽  
pp. 1055 ◽  
Author(s):  
Katie Emery ◽  
Allan Young ◽  
J. Arokianathar ◽  
Tell Tuttle ◽  
John Murphy
Keyword(s):  
Electron Donor ◽  
Single Electron

Comparing lactate and glycerol as a single-electron donor for sulfate reduction in fluidized bed reactors

2014 ◽  
Vol 25 (5) ◽  
pp. 719-733 ◽  
Author(s):  
Sueli M. Bertolino ◽  
Lucas A. Melgaço ◽  
Renata G. Sá ◽  
Versiane A. Leão
Keyword(s):  
Sulfate Reduction ◽  
Fluidized Bed ◽  
Electron Donor ◽  
Single Electron ◽  
Fluidized Bed Reactors

The single-electron hydrogen, lithium, and halogen bonds with HBe, H2B, and H3C radicals as the electron donor: an ab initio study

2011 ◽  
Vol 23 (2) ◽  
pp. 411-416 ◽  
Author(s):  
Qingzhong Li ◽  
Ran Li ◽  
Shichan Yi ◽  
Wenzuo Li ◽  
Jianbo Cheng
Keyword(s):  
Ab Initio ◽  
Electron Donor ◽  
Single Electron ◽  
Ab Initio Study ◽  
Halogen Bonds

A new ground state single electron donor for excess electron transfer studies in DNA

2009 ◽  
pp. 3583 ◽  
Author(s):  
Christian Trindler ◽  
Antonio Manetto ◽  
Jürgen Eirich ◽  
Thomas Carell
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Ground State ◽  
Excess Electron ◽  
Single Electron

Synthesis of α-deuterioalcohols by single-electron umpolung reductive deuteration of carbonyl using D2O as deuterium source

Synlett ◽  
2021 ◽  
Author(s):  
Hengzhao Li ◽  
Yuxia Hou ◽  
Zemin Lai ◽  
Lei ning ◽  
Ailing Li ◽  
...  
Keyword(s):  
Natural Products ◽  
Electron Donor ◽  
Potential Application ◽  
Functional Group ◽  
Chiral Center ◽  
Single Electron ◽  
Deuterium Incorporation ◽  
Broad Scope ◽  
High Yields

Deuterium incorporation can effectively stabilize the chiral centers of drug and agrochemical candidates that hampered by rapid in vivo racemization. In this work, the synthetically challenging chiral center deuteration of alcohols has been achieved via a single-electron umpolung reductive deuteration protocol using benign D2O as deuterium source and mild SmI2 as electron donor. The broad scope and excellent functional group tolerance of this method has been showcased by the synthesis of 43 respective α-deuterioalcohols in high yields and ≥98% deuterium incorporations. The potential application of this versatile method has been exemplified in the synthesis of 6 deuterated drug derivatives, 1 deuterated human hormone and 3 deuterated natural products. This method using D2O is greener and more efficient compared to traditional pyrophoric metal deuteride mediated reductive deuterations.

scholarly journals With or without light: comparing the reaction mechanism of dark-operative protochlorophyllide oxidoreductase with the energetic requirements of the light-dependent protochlorophyllide oxidoreductase

2014 ◽  
Author(s):  
Pedro J Silva
Keyword(s):  
Reaction Mechanism ◽  
Electron Donor ◽  
Ph Dependence ◽  
Single Point ◽  
Enzyme Reaction ◽  
Single Electron ◽  
Simple Explanation ◽  
Dependent Manner ◽  
Protochlorophyllide Oxidoreductase ◽  
Sequence Of Events

The addition of two electrons and two protons to the C17=C18 bond in protochlorophyllide is catalyzed by a light-dependent enzyme relying on NADPH as electron donor, and by a light-independent enzyme bearing a (Cys)3Asp-ligated [4Fe-4S] cluster which is reduced by cytoplasmic electron donors in an ATP-dependent manner and then functions as electron donor to protochlorophyllide. The precise sequence of events occurring at the C17=C18 bond has not, however, been determined experimentally in the dark-operating enzyme. In this paper, we present the computational investigation of the reaction mechanism of this enzyme at the B3LYP/6-311+G(d,p)// B3LYP/6-31G(d) level of theory. The reaction mechanism begins with single-electron reduction of the substrate by the (Cys)3Asp-ligated [4Fe-4S], yielding a negatively-charged intermediate. Depending on the rate of Fe-S cluster re-reduction, the reaction either proceeds through double protonation of the single-electron-reduced substrate, or by alternating proton/electron transfer. The computed reaction barriers suggest that Fe-S cluster re-reduction should be the rate-limiting stage of the process. Poisson-Boltzmann computations on the full enzyme-substrate complex, followed by Monte Carlo simulations of redox and protonation titrations revealed a hitherto unsuspected pH-dependence of the reaction potential of the Fe-S cluster. Furthermore, the computed distributions of protonation states of the His, Asp and Glu residues were used in conjunction with single-point ONIOM computations to obtain, for the first time, the influence of all protonation states of an enzyme on the reaction it catalyzes. Despite exaggerating the ease of reduction of the substrate, these computations confirmed the broad features of the reaction mechanism obtained with the medium-sized models, and afforded valuable insights on the influence of the titratable amino acids on each reaction step. Additional comparisons of the energetic features of the reaction intermediates with those of common biochemical redox intermediates suggest a surprisingly simple explanation for the mechanistic differences between the dark-catalyzed and light-dependent enzyme reaction mechanisms.

scholarly journals IMPURITY OF IRON A Y OF IRON ATOMS IN THE VI OMS IN THE VITREOUS ARSENIC TREOUS ARSENIC SELENIDE (As2Se3). ELEC SELENIDE (As2Se3). ELECTRONIC EX TRONIC EXCHANGE BE ANGE BETWEEN CENTERS OF IRON

2020 ◽  
Vol 4 (4) ◽  
pp. 39-47
Author(s):  
Kudrat Umarovich Bobokhuzhaev ◽  
◽  
Alla Valentinovna Marchenko ◽  
Pavel Pavlovich Seregin ◽  
Nelia Rinadovna Begisheva ◽  
...  
Keyword(s):  
Fermi Level ◽  
Band Gap ◽  
Conduction Band ◽  
Electron Donor ◽  
Iron Concentration ◽  
Spectroscopy Method ◽  
Single Electron ◽  
Electron States ◽  
Level Shifts ◽  
Arsenic Selenide

Iron atoms in vitreous arsenic selenide films form single electron donor centers, while the Fermi level shifts from the middle of the band gap to the bottom of the conduction band with an increase in the iron concentration due to the filling of single electron states of the acceptor type located below the Fermi level The Mössbauer spectroscopy method was used to study the electronic exchange between ionized and neutral centers of iron in the glassy selenide of arsenic

scholarly journals With or without light: comparing the reaction mechanism of dark-operative protochlorophyllide oxidoreductase with the energetic requirements of the light-dependent protochlorophyllide oxidoreductase

2014 ◽  
Author(s):  
Pedro J Silva
Keyword(s):  
Reaction Mechanism ◽  
Electron Donor ◽  
Ph Dependence ◽  
Single Point ◽  
Enzyme Reaction ◽  
Single Electron ◽  
Simple Explanation ◽  
Dependent Manner ◽  
Protochlorophyllide Oxidoreductase ◽  
Sequence Of Events

The addition of two electrons and two protons to the C17=C18 bond in protochlorophyllide is catalyzed by a light-dependent enzyme relying on NADPH as electron donor, and by a light-independent enzyme bearing a (Cys)3Asp-ligated [4Fe-4S] cluster which is reduced by cytoplasmic electron donors in an ATP-dependent manner and then functions as electron donor to protochlorophyllide. The precise sequence of events occurring at the C17=C18 bond has not, however, been determined experimentally in the dark-operating enzyme. In this paper, we present the computational investigation of the reaction mechanism of this enzyme at the B3LYP/6-311+G(d,p)// B3LYP/6-31G(d) level of theory. The reaction mechanism begins with single-electron reduction of the substrate by the (Cys)3Asp-ligated [4Fe-4S], yielding a negatively-charged intermediate. Depending on the rate of Fe-S cluster re-reduction, the reaction either proceeds through double protonation of the single-electron-reduced substrate, or by alternating proton/electron transfer. The computed reaction barriers suggest that Fe-S cluster re-reduction should be the rate-limiting stage of the process. Poisson-Boltzmann computations on the full enzyme-substrate complex, followed by Monte Carlo simulations of redox and protonation titrations revealed a hitherto unsuspected pH-dependence of the reaction potential of the Fe-S cluster. Furthermore, the computed distributions of protonation states of the His, Asp and Glu residues were used in conjunction with single-point ONIOM computations to obtain, for the first time, the influence of all protonation states of an enzyme on the reaction it catalyzes. Despite exaggerating the ease of reduction of the substrate, these computations confirmed the broad features of the reaction mechanism obtained with the medium-sized models, and afforded valuable insights on the influence of the titratable amino acids on each reaction step. Additional comparisons of the energetic features of the reaction intermediates with those of common biochemical redox intermediates suggest a surprisingly simple explanation for the mechanistic differences between the dark-catalyzed and light-dependent enzyme reaction mechanisms.

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