Structure and isomerization phenomena of olefin radical ions. 1,2-Bis(N-methyl-4-pyridiumyl)ethylene tetrafluoroborate radical cation

1972 ◽  
Vol 37 (10) ◽  
pp. 1485-1491 ◽  
Author(s):  
John W. Happ ◽  
John A. Ferguson ◽  
David G. Whitten
Keyword(s):  
Radical Cation ◽  
Radical Ions

Radikalionen, 61 [1, 2]Dialkylamino-substituierte Acetylene und Allene:Ionisation, Oxidation und AlCl3-katalysierte Wasserstoffübertragung / Radical Ions, 61 [1, 2]Dialkylamino-substituted Acetylenes and Allenes:Ionisation, Oxidation and AlCl3-Catalyzed Hydrogen Transfer

1984 ◽  
Vol 39 (6) ◽  
pp. 763-770 ◽  
Author(s):  
Hans Bock ◽  
Wolfgang Kaim ◽  
Mitsuo Kira ◽  
Louis Réné ◽  
Heinz-Günther Viehe
Keyword(s):  
Radical Cation ◽  
Hydrogen Transfer ◽  
Radical Cations ◽  
Esr Spectra ◽  
Ionization Potentials ◽  
Radical Ions ◽  
Substituted Acetylenes

AbstractThe photoelectron (PE) spectra of bis(dialkylamino) acetylenes R2N-C≡C-NR2 and of tetrakis(dialkylamino) allenes (R2N)2C=C=C(NR2)2 with R = CH3, C2H5 exhibit characteristic ionization patterns which are assigned to π radical cation states of the two molecular halves twisted against each other. The low first ionization potentials between 7.0 eV and 7.7 eV stimu­lated attempts to oxidize using AlCl3 in H2CCl2 or D2CCl2. The hyperfine structured ESR spectra observed can be unequivocally assigned to the ethylene radical cations R2N-HC=CH -NR2˙⊕ which are formed from the obviously non-persistent species R2N-C≡C-NR2˙⊕ via a hydrogen transfer. During the oxidation of the dialkylamino-substituted allenes no paramagnetic intermedi­ates could be detected, presumably due to a rapid dimerisation of the allene radical cation (R2N)2C=C=C(NR2)2˙⊕.

Radical ions in photochemistry. 18. The photosensitized (electron transfer) tautomerization of alkenes; the 1,1-diphenyl alkene system

1987 ◽  
Vol 65 (9) ◽  
pp. 2312-2314 ◽  
Author(s):  
Donald R. Arnold ◽  
Shelley A. Mines
Keyword(s):  
Hydrogen Bond ◽  
Electron Transfer ◽  
Radical Cation ◽  
Radical Anion ◽  
Relative Rate ◽  
Radical Cations ◽  
Radical Ions ◽  
Back Electron Transfer ◽  
Ambident Anion ◽  
Determining Factor

The photosensitized (electron transfer) irradiation of several conjugated 1,1-diphenyl alkenes, in acetonitrile with 1,4-dicyanobenzene or 1-cyanonapthalene as electron accepting sensitizer and 2,6-lutidine as base, leads essentially quantitatively to tautomerization to the less stable unconjugated isomer(s). The proposed mechanism for this reaction involves formation of the alkene radical cation and sensitizer radical anion followed by deprotonation of the radical cation, reduction of the resulting radical to the ambident anion by back electron transfer from the radical anion, and reprotonation. There are several steps in this mechanism that could control the ratio of isomers. Evidence is provided that, at least in some cases, it is the relative rate of deprotonation from the isomeric radical cations that is the determining factor. This rate is influenced by the conformation of the radical cation; the carbon–hydrogen bond involved in the deprotonation step must overlap with the singly occupied molecular orbital.

scholarly journals Frequencies and Normal Modes of Vibration of Benz[a]anthracene Radical Ions

2005 ◽  
Vol 60 (3) ◽  
pp. 158-164
Author(s):  
Rehab M. Kubba ◽  
Raghida I. Al-ani ◽  
Muthana Shanshal
Keyword(s):  
Radical Cation ◽  
Normal Modes ◽  
Equilibrium Geometry ◽  
Vibration Frequencies ◽  
Radical Ions ◽  
Normal Coordinates ◽  
Bond Alternation ◽  
Out Of Plane ◽  
Modes Of Vibration ◽  
Stretching Vibrations

MINDO/3-FORCES calculations were carried out for the radical ions of benz[a]anthracene. Both ions exhibit Cs symmetry with C-C bond alternation in all four rings. The obtained equilibrium geometry was applied for the calculation of all 3N − 6 vibration frequencies of each ion, and for the analysis of their normal coordinates. The so calculated frequencies of the radical cation were close to the experimental frequencies and those of the ab initio calculations. They fall in the ranges νCHstr. (3034 - 3087 cm−1), νCCstr. (1237 - 1609 cm−1), δCH (1142 - 1216 cm−1). Interesting correlations could be obtained for the frequencies of similar vibrations, e. g. νsymCHstr. >νasymCHstr. Exception is the frequency of vibration of CHα in ring A for the radical cation and the same bond in ring D for the radical anion. The vibration frequencies for the CH bonds depend on the σ -electron densities of the corresponding carbon atoms, i. e. νCH.+str. >νCHstr. >νCH.−str., where σ −ρĊ+ >σ −ρC >σ −ρĊ− . For the C-C stretching vibrations the relation ν(C-C)str. >ν(C-C).−str. >ν(C-C).+str. holds, with the exception of the Cβ -Cβ bond, for which the relation ν(C-C)str. >ν(C-C).+str. >ν(C-C).−str. is found. As for the in-plane and out of-plane deformations, the following general correlations δ (CH) >δ (CH).− >δ (CH).+ and γ (CC) >γ (CC).− >γ (CC).+.

Radikalionen, 62 [ 1—3]Bis(dimethyIamino)dibenzoheptafulven-Radikalkation /Radical Ions, 62 [1—3]Bis(dimethylamino)dibenzoheptafulvene Radical Cation

1984 ◽  
Vol 39 (6) ◽  
pp. 771-777 ◽  
Author(s):  
Hans Bock ◽  
Bernhard Roth ◽  
Jörg Daub
Keyword(s):  
Ionization Potential ◽  
Radical Cation ◽  
Ground State ◽  
Title Compound ◽  
Valence Electron ◽  
Esr Spectra ◽  
Vertical Ionization Potential ◽  
Radical Ions ◽  
Mndo Calculations ◽  
Multiplet Signal

AbstractThe neutral title compound, 8,8-bis(dimethylamino)dibenzo-[a,d]-heptafulvene, exhibits a first vertical ionization potential of only 6.98 eV and, therefore, can also be oxidized by AlCl3 in H2CCl2 solution. The radical cation generated shows a complex multiplet signal pattern, which is assigned based on additional ENDOR measurements. The photoelectron (PE) and ESR spectra of the 112 valence electron molecule are interpreted by “pararneter-optimized” HMO and by geometry-optimized MNDO calculations, which both suggest a non-planar π-type ground state with most of the charge and the spin distributed over the dibenzoheptatriene part of the radical cation.

Radikalionen, 79 [1, 2] ESR-Nachweis von Tetra(methylthio)thiophen- und Tetra(methylthio)ethen-Radikalkationen bei der oxidativen Schwefelung von H3CS-C=C-SCH3 mit S2Cl2/AlCl3 und H3CSCl/AlCl3 / Radical Ions, 79 [1, 2] ESR Evidence for Tetra(methylthio)thiophene and Tetra(methylthio)ethene Radical Cations During the Oxidative Sulfuration of H3CS-C=C-SCH3 by S2Cl2/AlCl3 and H3CSCl/AlCl3

1988 ◽  
Vol 43 (4) ◽  
pp. 419-426 ◽  
Author(s):  
H. Bock ◽  
P. Rittmeyer
Keyword(s):  
Radical Cation ◽  
Radical Cations ◽  
Esr Spectra ◽  
Radical Ions ◽  
Acetylene Derivatives

AbstractDi(methylthio)acetylene H3CS-C≡C-SCH3 reacts with S2C12 in AlCl3/H2CCl2 solution to the tetra(thiomethyl)thiophene radical cation (H3CS)4C4S·⊕ and with H3CSCl to the tetra(thiomethyl)ethene radical cation (H3CS)2C·=⊕C(SCH3)3. Their ESR spectra are assigned by compari­son with literature data or those of analogous products obtained from other acetylene derivatives R-C≡C-R with R = SCH2CH3, CH3, C6H5 as well as based on HMO arguments. The possible course of the oxidative sulfuration is discussed.

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