Using Cyclic Voltammetry and Molecular Modeling To Determine Substituent Effects in the One-Electron Reduction of Benzoquinones

1998 ◽  
Vol 75 (3) ◽  
pp. 365 ◽  
Author(s):  
Janell E. Heffner ◽  
Jeffrey C. Raber ◽  
Owen A. Moe ◽  
Carl T. Wigal
Keyword(s):  
Cyclic Voltammetry ◽  
Molecular Modeling ◽  
Substituent Effects ◽  
Electron Reduction ◽  
The One

Das Reduktionsverhalten von Pentacarbonylpyridin-Komplexen des Chroms, Molybdäns und Wolframs / The Reduction Behaviour of Pentacarbonylpyridinechromium, -molybdenum and -tungsten Complexes

1984 ◽  
Vol 39 (6) ◽  
pp. 801-807 ◽  
Author(s):  
Wolfgang Kaim
Keyword(s):  
Cyclic Voltammetry ◽  
Substituent Effects ◽  
Heterocyclic Ligand ◽  
Tungsten Complexes ◽  
Spin Resonance ◽  
Reduction Behaviour ◽  
Lowest Unoccupied Molecular Orbital ◽  
Primary Reduction ◽  
Electron Reduction ◽  
The One

AbstractThe reduction of group VIB metal pentacarbonyl complexes and of iodomethylates of 4- trimethylsilyl-, 4-acetyl- and 4-cyanopyridine has been investigated. Informations on the dissociation of the complexes and on the potential and reversibility of the one-electron reduction were obtained by cyclic voltammetry in DMF, whereas electron spin resonance (ESR) studies of the primary reduction products in the 4-acetylpyridine series revealed the distribution of the unpaired electron. The results suggest that the lowest unoccupied molecular orbital (LUMO) is a ligand centered π*-orbital in the 4-acetyl- and 4-cyanopyridine complexes, thus confirming assignments from photochemistry. The results allow an assessment of both N-coordination and substituent effects at the heterocyclic ligand.

scholarly journals One-Electron Reduction Potentials: Calibration of Theoretical Protocols for Morita–Baylis–Hillman Nitroaromatic Compounds in Aprotic Media

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2129 ◽  
Author(s):  
Amauri Francisco da Silva ◽  
Antonio João da Silva Filho ◽  
Mário Vasconcellos ◽  
Otávio Luís de Santana
Keyword(s):  
Cyclic Voltammetry ◽  
Biological Activity ◽  
Chemical Structure ◽  
Reduction Potential ◽  
Chemical Reactivity ◽  
Nitroaromatic Compounds ◽  
Reduction Potentials ◽  
Electron Reduction ◽  
The One ◽  
Antileishmanial Activities

Nitroaromatic compounds—adducts of Morita–Baylis–Hillman (MBHA) reaction—have been applied in the treatment of malaria, leishmaniasis, and Chagas disease. The biological activity of these compounds is directly related to chemical reactivity in the environment, chemical structure of the compound, and reduction of the nitro group. Because of the last aspect, electrochemical methods are used to simulate the pharmacological activity of nitroaromatic compounds. In particular, previous studies have shown a correlation between the one-electron reduction potentials in aprotic medium (estimated by cyclic voltammetry) and antileishmanial activities (measured by the IC50) for a series of twelve MBHA. In the present work, two different computational protocols were calibrated to simulate the reduction potentials for this series of molecules with the aim of supporting the molecular modeling of new pharmacological compounds from the prediction of their reduction potentials. The results showed that it was possible to predict the experimental reduction potential for the calibration set with mean absolute errors of less than 25 mV (about 0.6 kcal·mol−1).

Electrochemical Studies of Organotitanium Nitrogen Fixation Systems

1973 ◽  
Vol 51 (6) ◽  
pp. 815-820 ◽  
Author(s):  
T. Chivers ◽  
E. D. Ibrahim
Keyword(s):  
Cyclic Voltammetry ◽  
Nitrogen Fixation ◽  
Electrochemical Reduction ◽  
Argon Atmosphere ◽  
Electrochemical Studies ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential ◽  
Electron Reduction ◽  
The One ◽  
Ether Solvents

The electrochemical reduction of compounds of the type (π-Cp)2Ti(R)Cl (R = Cl, CH3, C6H5, C5F5, OTiCl(π-Cp)2) in ether solvents has been studied using the techniques of polarography, controlled potential electrolysis, and cyclic voltammetry. The one-electron reduction products, presumably (π-Cp)2TiR (R = CH3, C6F5), are initially green in tetrahydrofuran but, in a dinitrogen or argon atmosphere, they form intensely blue solutions which result from the reaction of (π-Cp)2TiR with tetrahydrofuran solvent.

scholarly journals Redox and Antioxidant Modulation of Circadian Rhythms: Effects of Nitroxyl, N-Acetylcysteine and Glutathione

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2514
Author(s):  
Santiago Andrés Plano ◽  
Fernando Martín Baidanoff ◽  
Laura Lucía Trebucq ◽  
Sebastián Ángel Suarez ◽  
Fabio Doctorovich ◽  
...  
Keyword(s):  
Soluble Guanylate Cyclase ◽  
Phase Locking ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Circadian Phase ◽  
Subjective Night ◽  
Circadian Time ◽  
Electron Reduction ◽  
Locomotor Rhythms ◽  
The One

The circadian clock at the hypothalamic suprachiasmatic nucleus (SCN) entrains output rhythms to 24-h light cycles. To entrain by phase-advances, light signaling at the end of subjective night (circadian time 18, CT18) requires free radical nitric oxide (NO•) binding to soluble guanylate cyclase (sGC) heme group, activating the cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG). Phase-delays at CT14 seem to be independent of NO•, whose redox-related species were yet to be investigated. Here, the one-electron reduction of NO• nitroxyl was pharmacologically delivered by Angeli’s salt (AS) donor to assess its modulation on phase-resetting of locomotor rhythms in hamsters. Intracerebroventricular AS generated nitroxyl at the SCN, promoting phase-delays at CT14, but potentiated light-induced phase-advances at CT18. Glutathione/glutathione disulfide (GSH/GSSG) couple measured in SCN homogenates showed higher values at CT14 (i.e., more reduced) than at CT18 (oxidized). In addition, administration of antioxidants N-acetylcysteine (NAC) and GSH induced delays per se at CT14 but did not affect light-induced advances at CT18. Thus, the relative of NO• nitroxyl generates phase-delays in a reductive SCN environment, while an oxidative favors photic-advances. These data suggest that circadian phase-locking mechanisms should include redox SCN environment, generating relatives of NO•, as well as coupling with the molecular oscillator.

Kinetics and mechanism of oxidation of N,N′-dimethyl-9,9′-biacridanyl by some π acceptors and a one-electron oxidant

1985 ◽  
Vol 63 (2) ◽  
pp. 445-451 ◽  
Author(s):  
Allan K. Colter ◽  
Charles C. Lai ◽  
A. Gregg Parsons ◽  
N. Bruce Ramsey ◽  
Gunzi Saito
Keyword(s):  
Electron Transfer ◽  
Reduction Potential ◽  
Isotope Effects ◽  
Substituent Effects ◽  
Kinetic Isotope Effects ◽  
Spin Trapping ◽  
Single Electron Transfer ◽  
Kinetic Isotope ◽  
The One ◽  
Rule Out

Oxidation of N,N′-dimethyl-9,9′-biacridanyl (DD) has been investigated as a model for single electron transfer (SET)-initiated oxidation of NADH coenzyme models such as N-methylacridan (DH). Oxidants investigated cover a 1010-fold range of reactivity in acetonitrile and include the π acceptors 1,4-benzoquinone (BQ), 2,6-dichloro-1,4-benzoquinone (DCIBQ), p-chloranil (CA), 2,3-dicyanobenzoquinone (DCBQ), 2,3-dicyano-1,4-naphthoquinone (DCNQ), 2,3-dicyano-5-nitro-1,4-naphthoquinone (DCNNQ), 9-dicyanomethylene-2,4,7-trinitrofluorene (DCMTNF), 9-dicyanomethylene-2,4,5,7-tetranitrofluorene (DCMTENF), 7,7,8,8-tetracyanoquinodimethane (TCNQ), and tetracyanoethylene (TCNE), and the one-electron oxidant tris(2,2′-bipyridyl)cobalt(III), [Formula: see text] The oxidation product is, in every case, N-methylacridinium ion (D+). A mechanism involving a rate-determining electron transfer with simultaneous fragmentation to D+ and N-methyl-9-acridanyl radical (D•) is proposed. This mechanism is supported by the observed dependence of the rate on oxidant reduction potential, by spin-trapping experiments, by kinetic isotope effects in oxidation of 9,9′-dideuterio-DD, and by substituent effects in oxidation of 2,2′- and 3,3′-dimethoxy-DD. The rate of oxidation of DD relative to that of DH is 3.4 × 102 with [Formula: see text] and with the π acceptors varies from ea. 0.3 (BQ) to 8.1 × 104 (DCMTENF). The results rule out a SET-initiated mechanism for oxidation of DH by all of the oxidants studied except TCNQ and DCMTENF.

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