Electron Transfer between Two Silyl-Substituted Phenylene Rings:  EPR/ENDOR Spectra, DFT Calculations, and Crystal Structure of the One-Electron Reduction Compound of a Di(m-silylphenylenedisiloxane)

2003 ◽  
Vol 125 (15) ◽  
pp. 4487-4494 ◽  
Author(s):  
Cosmina Dutan ◽  
Sylvie Choua ◽  
Théo Berclaz ◽  
Michel Geoffroy ◽  
Nicolas Mézailles ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Transfer ◽  
Dft Calculations ◽  
Electron Reduction ◽  
The One

scholarly journals Reduction of ferric haemoproteins by tetrahydropterins: a kinetic study

2005 ◽  
Vol 392 (3) ◽  
pp. 583-587 ◽  
Author(s):  
Chantal Capeillere-Blandin ◽  
Delphine Mathieu ◽  
Daniel Mansuy
Keyword(s):  
Electron Transfer ◽  
Cytochrome C ◽  
Cytochrome B5 ◽  
Reduction Rate ◽  
Cation Radical ◽  
Order Reduction ◽  
Reduction Potentials ◽  
Electron Reduction ◽  
The One

We previously showed that one-electron transfer from tetrahydropterins to iron porphyrins is a very general reaction, with formation of an intermediate cation radical similar to the one detected in NO synthase. As a model reaction, the rates of reduction of eight haemoproteins by diMePH4 (6,7-dimethyltetrahydropterin) have been studied and correlated with their one-electron reduction potentials, Em (FeIII/FeII). On the basis of kinetic data analyses, a bimolecular collisional mechanism is proposed for the electron transfer from diMePH4 to ferrihaemoproteins. Haemoproteins with reduction potentials below −160 mV were shown not to be reduced by diMePH4 to the corresponding ferrohaemoproteins. For haemoproteins with reduction potentials more positive than −160 mV, such as chloroperoxidase, cytochrome b5, methaemoglobin and cytochrome c, there was a good correlation between the second-order reduction rate constant and the redox potential, Em (FeIII/FeII):The rate of reduction of cytochrome c by BH4 [(6R)-5,6,7,8-tetrahydrobiopterin] was determined to be similar to that of the reduction of cytochrome c by diMePH4. These results confirm the role of tetrahydropterins as one-electron donors to FeIII porphyrins.

The photochemistry of Ru(bpy)32+ in basic medium

1982 ◽  
Vol 60 (22) ◽  
pp. 2856-2858 ◽  
Author(s):  
Jin-Gou Xu ◽  
Gerald B. Porter
Keyword(s):  
Electron Transfer ◽  
Methyl Viologen ◽  
Reduction Product ◽  
Basic Medium ◽  
Electron Reduction ◽  
The One

Ru(bpy)32+ is photodecomposed in 0.3 M NaOH with [Formula: see text]. With methyl viologen also present, electron transfer quenching of the luminescence is accompanied by formation of the one electron reduction product of methyl viologen, MV+. The Ru(bpy)33+ formed in the corresponding oxidation is rapidly reduced by either OH− or MV+ to Ru(II).

Interfacial interactions and the heterogeneous one-electron reduction of methyl viologen

1987 ◽  
Vol 52 (5) ◽  
pp. 1097-1114 ◽  
Author(s):  
Michael Heyrovský ◽  
Ladislav Novotný
Keyword(s):  
Electron Transfer ◽  
Radical Cation ◽  
Electrode Surface ◽  
Methyl Viologen ◽  
Potential Range ◽  
Standard Redox Potential ◽  
Mercury Electrodes ◽  
Electron Reduction ◽  
The One ◽  
Surface Redox

The one-electron reversible electroreduction of methyl viologen to its radical cation in aqueous solutions on mercury electrodes proceeds, according to potential, concentration and time of electrolysis, in various ways. Methyl viologen is adsorbed in flat orientation at the electrode surface; it undergoes a surface redox process in π-interaction with the metal in a potential range positive by about 0.2 V of the beginning of the electroreduction. The actual reduction starts by electron transfer followed by adsorption of the radical cation and, at higher concentrations and in a narrow potential range, by crystallization at the electrode surface of a salt of the radical cation. In solution near the electrode the radical cation dimerizes and the dimer also adsorbs at the electrode. In the region of the standard redox potential and more negative the reduction proceeds by electron transfer from the electrode covered by a layer of the radical cation or of its dimer.

Computationally Assisted Design of High Signal-to-Noise Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes

2020 ◽  
Author(s):  
Rishikesh Kulkarni ◽  
Anneliese Gest ◽  
Chun Kei Lam ◽  
Benjamin Raliski ◽  
Feroz James ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Photoinduced Electron Transfer ◽  
Density Functional ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Md Simulations ◽  
High Signal ◽  
Signal To Noise ◽  
Green Fluorescent

<p>High signal-to-noise optical voltage indicators will enable simultaneous interrogation of membrane potential in large ensembles of neurons. However, design principles for voltage sensors with high sensitivity and brightness remain elusive, limiting the applicability of voltage imaging. In this paper, we use molecular dynamics (MD) simulations and density functional theory (DFT) calculations to guide the design of a bright and sensitive green-fluorescent voltage-sensitive fluorophore, or VoltageFluor (VF dye), that uses photoinduced electron transfer (PeT) as a voltage-sensing mechanism. MD simulations predict an 11% increase in sensitivity due to membrane orientation, while DFT calculations predict an increase in fluorescence quantum yield, but a decrease in sensitivity due to a decrease in rate of PeT. We confirm these predictions by synthesizing a new VF dye and demonstrating that it displays the expected improvements by doubling the brightness and retaining similar sensitivity to prior VF dyes. Combining theoretical predictions and experimental validation has resulted in the synthesis of the highest signal-to-noise green VF dye to date. We use this new voltage indicator to monitor the electrophysiological maturation of human embryonic stem cell-derived medium spiny neurons. </p>

Crystal structure, spectroscopic, DFT calculations and antimicrobial study of the Cu(II) complex bearing second-generation quinolone ofloxacin and 2,2′-bipyridine

2021 ◽  
Vol 519 ◽  
pp. 120264
Author(s):  
Joshua Ayoola Obaleye ◽  
Misitura Lawal ◽  
Rajendrasinh N. Jadeja ◽  
Vivek Kumar Gupta ◽  
Ginikachukwu Grace Nnabuike ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dft Calculations ◽  
Second Generation ◽  
Antimicrobial Study

scholarly journals Autocatalytic photoredox Chan-Lam coupling of free diaryl sulfoximines with arylboronic acids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cong Wang ◽  
Hui Zhang ◽  
Lucille A. Wells ◽  
Tian Liu ◽  
Tingting Meng ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom Abstraction ◽  
Coupling Reactions ◽  
Ambient Light ◽  
Environmental Friendliness ◽  
Copper Species ◽  
Arylboronic Acids ◽  
Ligand Free ◽  
Byproduct Formation ◽  
Electron Reduction

AbstractN-Arylation of NH-sulfoximines represents an appealing approach to access N-aryl sulfoximines, but has not been successfully applied to NH-diaryl sulfoximines. Herein, a copper-catalyzed photoredox dehydrogenative Chan-Lam coupling of free diaryl sulfoximines and arylboronic acids is described. This neutral and ligand-free coupling is initiated by ambient light-induced copper-catalyzed single-electron reduction of NH-sulfoximines. This electron transfer route circumvents the sacrificial oxidant employed in traditional Chan-Lam coupling reactions, increasing the environmental friendliness of this process. Instead, dihydrogen gas forms as a byproduct of this reaction. Mechanistic investigations also reveal a unique autocatalysis process. The C–N coupling products, N-arylated sulfoximines, serve as ligands along with NH-sulfoximine to bind to the copper species, generating the photocatalyst. DFT calculations reveal that both the NH-sulfoximine substrate and the N-aryl product can ligate the copper accounting for the observed autocatalysis. Two energetically viable stepwise pathways were located wherein the copper facilitates hydrogen atom abstraction from the NH-sulfoximine and the ethanol solvent to produce dihydrogen. The protocol described herein represents an appealing alternative strategy to the classic oxidative Chan-Lam reaction, allowing greater substrate generality as well as the elimination of byproduct formation from oxidants.

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