Stereochemical Memory in the Regioselective and Diastereoselective Rearrangement of Tricyclo[3.3.0.02,4]octanes (Housanes) by Electron Transfer (1,3-Cyclopentanediyl Radical Cations) and Acid (Cyclopentyl Carbenium Ions) and Silver-Ion Catalysis

2003 ◽  
Vol 125 (4) ◽  
pp. 995-1001 ◽  
Author(s):  
Waldemar Adam ◽  
Christian P. Librera ◽  
Frank-Gerrit Klärner ◽  
Frank Wurche
Keyword(s):  
Electron Transfer ◽  
Radical Cations ◽  
Silver Ion ◽  
Carbenium Ions

scholarly journals Spectral Probe for Electron Transfer and Addition Reactions of Azide Radicals with Substituted Quinoxalin-2-Ones in Aqueous Solutions

2021 ◽  
Vol 22 (2) ◽  
pp. 633
Author(s):  
Konrad Skotnicki ◽  
Slawomir Ostrowski ◽  
Jan Cz. Dobrowolski ◽  
Julio R. De la Fuente ◽  
Alvaro Cañete ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Density Functional ◽  
Reduction Potential ◽  
Biological Significance ◽  
Radical Cations ◽  
Basis Sets ◽  
Double Bonds ◽  
Reduction Potentials

The azide radical (N3●) is one of the most important one-electron oxidants used extensively in radiation chemistry studies involving molecules of biological significance. Generally, it was assumed that N3● reacts in aqueous solutions only by electron transfer. However, there were several reports indicating the possibility of N3● addition in aqueous solutions to organic compounds containing double bonds. The main purpose of this study was to find an experimental approach that allows a clear assignment of the nature of obtained products either to its one-electron oxidation or its addition products. Radiolysis of water provides a convenient source of one-electron oxidizing radicals characterized by a very broad range of reduction potentials. Two inorganic radicals (SO4●−, CO3●−) and Tl2+ ions with the reduction potentials higher, and one radical (SCN)2●− with the reduction potential slightly lower than the reduction potential of N3● were selected as dominant electron-acceptors. Transient absorption spectra formed in their reactions with a series of quinoxalin-2-one derivatives were confronted with absorption spectra formed from reactions of N3● with the same series of compounds. Cases, in which the absorption spectra formed in reactions involving N3● differ from the absorption spectra formed in the reactions involving other one-electron oxidants, strongly indicate that N3● is involved in the other reaction channel such as addition to double bonds. Moreover, it was shown that high-rate constants of reactions of N3● with quinoxalin-2-ones do not ultimately prove that they are electron transfer reactions. The optimized structures of the radical cations (7-R-3-MeQ)●+, radicals (7-R-3-MeQ)● and N3● adducts at the C2 carbon atom in pyrazine moiety and their absorption spectra are reasonably well reproduced by density functional theory quantum mechanics calculations employing the ωB97XD functional combined with the Dunning’s aug-cc-pVTZ correlation-consistent polarized basis sets augmented with diffuse functions.

Surface photochemistry: Semiconductor mediated reactions of some 1,2-diarylcyclopropanes

1987 ◽  
Vol 65 (5) ◽  
pp. 976-979 ◽  
Author(s):  
Philip A. Carson ◽  
Paul de Mayo
Keyword(s):  
Electron Transfer ◽  
Radical Cations ◽  
Transfer Mechanism ◽  
Electron Transfer Mechanism ◽  
Trans Isomerization

1,2-Diphenylcyclopropane (1) was found to be oxidized on illuminated ZnO in the presence of air while 1-(p-methoxyphenyl)-2-phenylcyclopropane (2) and 1,2-bis(p-methoxyphenyl)cyclopropane (3) were found to be similarly oxidized on illuminated CdS. Compounds 2 and 3 were found, also, to undergo a rapid photochemical cis-trans isomerization on CdS whereas 1 did not undergo such isomerization. An electron transfer mechanism involving formation of the radical cations of the substrates is proposed.

scholarly journals Electron self-exchange activation parameters of diethyl sulfide and tetrahydrothiophene

2013 ◽  
Vol 9 ◽  
pp. 1448-1454
Author(s):  
Martin Goez ◽  
Martin Vogtherr
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Nuclear Polarization ◽  
Activation Barrier ◽  
Activation Parameters ◽  
Radical Cations ◽  
Free Energies ◽  
Time Resolved ◽  
Diethyl Sulfide ◽  
Chemically Induced

Electron transfer between the title compounds and their radical cations, which were generated by photoinduced electron transfer from the sulfides to excited 2,4,6-triphenylpyrylium cations, was investigated by time-resolved measurements of chemically induced dynamic nuclear polarization (CIDNP) in acetonitrile. The strongly negative activation entropies provide evidence for an associative–dissociative electron exchange involving dimeric radical cations. Despite this mechanistic complication, the free energies of activation were found to be well reproduced by the Marcus theory of electron transfer, with the activation barrier still dominated by solvent reorganization.

ChemInform Abstract: ELECTRON TRANSFER BETWEEN TETRAALKYLHYDRAZINE RADICAL CATIONS AND TETRAALKYLHYDRAZINES

1975 ◽  
Vol 6 (44) ◽  
pp. no-no
Author(s):  
S. F. NELSEN ◽  
P. J. HINTZ ◽  
J. M. BUSCHEK ◽  
G. R. WEISMAN
Keyword(s):  
Electron Transfer ◽  
Radical Cations

Free electron transfer from several phenols to radical cations of non-polar solvents

2000 ◽  
Vol 2 (21) ◽  
pp. 4947-4955 ◽  
Author(s):  
Mahalaxmi R. Ganapathi ◽  
Ralf Hermann ◽  
Sergei Naumov ◽  
Ortwin Brede
Keyword(s):  
Electron Transfer ◽  
Free Electron ◽  
Radical Cations ◽  
Polar Solvents
Sign in / Sign up

Export Citation Format

Share Document