Electrochemical investigation of radical-anion reactions of 5-nitro-2-furfuryl derivatives

1984 ◽  
Vol 49 (7) ◽  
pp. 1627-1634
Author(s):  
Jiří Klíma ◽  
Josef Prousek ◽  
Jiří Ludvík ◽  
Jiří Volke
Keyword(s):  
Nucleophilic Substitution ◽  
Radical Anion ◽  
Esr Spectroscopy ◽  
Supporting Electrolyte ◽  
Electrochemical Investigation ◽  
Reduction Step ◽  
Nucleophilic Agent ◽  
Dc Polarography ◽  
Primary Reduction

In the studies on nucleophilic substitution of 5-nitro-2-furfuryl derivatives the function of nucleophilic agent was substituted by electrolysis. The electrochemical reduction of these substances and the follow-up reactions of the intermediates were studied by cyclic voltammetry, dc-polarography and ESR spectroscopy. The primary reduction step is the uptake of a single electron giving rise to the radical anion R-CH2-X- which spontaneously splits off the anion X- and forms the neutral 5-nitro-2-furfuryl radical R-CH2.. This radical may either dimerize to 1,2-bis(5-nitro-2-furyl)ethane or yield 5-nitro-2-methylfuran (VI) through abstraction of hydrogen from the solvent or from the supporting electrolyte or through the uptake of an electron and the following protonation. The mechanism found here confirms the validity of the formerly suggested radical-anion mechanism in the nucleophilic substitution of some 5-nitro-2-furfuryl derivatives.

Association of radical anion with alkali cations. IV. ESR study of the 4-nitrobenzophenone radical anion

1980 ◽  
Vol 45 (2) ◽  
pp. 369-375 ◽  
Author(s):  
Stanislav Miertuš ◽  
Ondrej Kyseľ
Keyword(s):  
Hyperfine Splitting ◽  
Radical Anion ◽  
Esr Spectroscopy ◽  
Supporting Electrolyte ◽  
Esr Spectra ◽  
Proton Donor ◽  
Alkali Cations

The 4-nitrobenzophenone radical anion prepared by electrolysis was studied by ESR spectroscopy. On the basis of the interpretation of ESR spectra, the conformation of this system was estimated. The effect of the concentration of supporting electrolyte and of the presence of a proton-donor agent (C2H5OH) was examined. It is assumed that changes in hyperfine splitting constants are caused by association.

Electrochemical behaviour and ESR spectra of nitro substituted mono- and dibenzoylmethylenebenzthiazolines and selenazolines

1979 ◽  
Vol 44 (5) ◽  
pp. 1540-1551 ◽  
Author(s):  
Jaro Komenda ◽  
Jiří Huzlík
Keyword(s):  
Electron Transfer ◽  
Esr Spectroscopy ◽  
Electrochemical Behaviour ◽  
Spectroscopic Studies ◽  
Esr Spectra ◽  
Slow Electron

Compounds of the type of 2-(4'-nitrobenzoyl)methylene-3-ethylbenzothiazoline (I) and 2-bis-(p-nitrobenzoyl)methylene-3-ethylbenzothiazoline (II) were studied polarographically and by ESR spectroscopy to obtain informations about their electrochemical and follow-up reactions and their conformation. Whereas with compounds of the type I the conjugation in their molecules is preserved, with type II the coplanarity of the molecules is disturbed, which is manifested in the values of the splitting constants of the ESR spectra and a slow electron transfer between both nitrophenyl substituents. These conclusions are supported by NMR spectroscopic studies.

Stability of radical anions derived from substituted 5-nitrofurans investigated by ESR spectroscopy

1985 ◽  
Vol 50 (7) ◽  
pp. 1594-1601 ◽  
Author(s):  
Jiří Klíma ◽  
Larisa Baumane ◽  
Janis Stradinš ◽  
Jiří Volke ◽  
Romualds Gavars
Keyword(s):  
Radical Anion ◽  
High Stability ◽  
Esr Spectroscopy ◽  
Reaction Path ◽  
Order Reaction ◽  
Second Order ◽  
Radical Anions ◽  
Second Order Reaction ◽  
Unpaired Electron Density ◽  
The Stability

It has been found that the decay in dimethylformamide and dimethylformamide-water mixtures of radical anions in five of the investigated 5-nitrofurans is governed by a second-order reaction. Only the decay of the radical anion generated from 5-nitro-2-furfural III may be described by an equation including parallel first- and second-order reactions; this behaviour is evidently caused by the relatively high stability of the corresponding dianion, this being an intermediate in the reaction path. The presence of a larger conjugated system in the substituent in position 2 results in a decrease of the unpaired electron density in the nitro group and, consequently, an increase in the stability of the corresponding radical anions.

Kinetics of electroreduction of Zn2+ at mercury in nonaqueous solutions

1994 ◽  
Vol 72 (7) ◽  
pp. 1691-1698 ◽  
Author(s):  
Mariléa Manzini ◽  
Andrzej Lasia
Keyword(s):  
Cyclic Voltammetry ◽  
Charge Transfer ◽  
Supporting Electrolyte ◽  
Donor Number ◽  
Nonaqueous Solutions ◽  
Dc Polarography ◽  
One Step ◽  
A Charge ◽  
Tetraethylammonium Perchlorate ◽  
Kinetics Of

The electroreduction of Zn2+ was studied in propylene carbonate (PC), acetonitrile (ACN), and hexamethylphosphoramide (HMPA) on mercury at various concentrations of tetraethylammonium perchlorate as a supporting electrolyte using dc polarography, cyclic voltammetry, chronoamperometry, and ac polarography. It was found that in PC and ACN the electroreduction process proceeds in one step. In HMPA, however, the electroreduction proceeds through a CEE mechanism in which a chemical reaction is followed by a charge transfer in two steps. The heterogeneous rate constants, corrected for the double layer effects, decrease with increase in the solvent donor number. The electroreduction process proceeds through the cation transfer mechanism.

ChemInform Abstract: A Study by ESR Spectroscopy of the Di-tert-butylsilanone Radical Anion

ChemInform ◽  
2010 ◽  
Vol 23 (50) ◽  
pp. no-no
Author(s):  
A. G. DAVIES ◽  
A. G. NEVILLE
Keyword(s):  
Radical Anion ◽  
Esr Spectroscopy

Structural features of 1,3,5-trifluorobenzene radical anion, as studied by optically detected ESR spectroscopy and quantum chemistry

2013 ◽  
Vol 62 (11) ◽  
pp. 2311-2316 ◽  
Author(s):  
S. V. Blinkova ◽  
M. M. Vyushkova ◽  
L. N. Shchegoleva ◽  
I. V. Beregovaya ◽  
V. A. Bagryansky ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Radical Anion ◽  
Esr Spectroscopy ◽  
Structural Features ◽  
Optically Detected

The cis–trans isomerization of the radical anion of biacetyl

1976 ◽  
Vol 54 (23) ◽  
pp. 3637-3640 ◽  
Author(s):  
A. John Elliot ◽  
Jeffrey K. S. Wan
Keyword(s):  
Radical Anion ◽  
Esr Spectroscopy ◽  
Solvent Composition ◽  
Trans Isomers ◽  
Trans Isomerization

The equilibrium between the cis and the trans isomers of the biacetyl radical anion has been studied by esr spectroscopy. The dependence of this equilibrium on the solvent composition and temperature was followed.

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