Analysis of the excess charge effect in alternant conjugated hydrocarbon radical-ions

1967 ◽  
Vol 71 (11) ◽  
pp. 3702-3704 ◽  
Author(s):  
James R. Bolton
Keyword(s):  
Excess Charge ◽  
Charge Effect ◽  
Hydrocarbon Radical ◽  
Radical Ions

scholarly journals Formation of intramolecular dimer radical ions of diphenyl sulfones

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kazumasa Okamoto ◽  
Shunpei Kawai ◽  
Takahiro Kozawa
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Radical Cations ◽  
Excess Charge ◽  
Radical Ions ◽  
Functional Theory ◽  
Aromatic Molecules ◽  
Diphenyl Sulfone ◽  
The Density Functional Theory ◽  
Phenyl Rings

AbstractDimer radical ions of aromatic molecules in which excess charge is localized in a pair of rings have been extensively investigated. While dimer radical cations of aromatics have been previously produced in the condensed phase, the number of molecules that form dimer anions is very limited. In this study, we report the formation of intramolecular dimer radical ions (cations and anions) of diphenyl sulfone derivatives (DPs) by electron beam pulse radiolysis in the liquid phase at room temperature. The density functional theory (DFT) calculations also showed the formation of the dimer radical ions. The torsion barrier of the phenyl ring of DPs was also calculated. It was found that the dimer radical ions show the larger barrier than the neutral state. Finally, stability of the dimer radical anion is dependent on not only the inductive effect of the sulfonyl group but the conjugation involving the d-orbital of the S atom and the phenyl rings.

Untersuchung von einfachen π-Elektronensystemen mit Hilfe von Elektronenspin-Resonanz und Polarographi

1965 ◽  
Vol 20 (9) ◽  
pp. 1102-1116 ◽  
Author(s):  
K. MöBius
Keyword(s):  
Negative Ion ◽  
Excess Charge ◽  
Radical Ions ◽  
Charge Effects ◽  
Half Wave ◽  
High Dielectric ◽  
Better Than ◽  
Alternant Radical ◽  
Spin Densities ◽  
G Factors

In order to test the results of the MO-theories of HÜCKEL and MCLACHLAN, spin densities and energies of unpaired electrons of 10 aromatic hydrocarbon radicals have been measured by EPR and polarography. Eight negative ion radicals have been prepared electrolytically in solvents of high dielectric constant. This technique is found to yield “free” solvated radical ions with spin densities and π-orbital energies not noticeably affected by the medium. By eliminating solvent effects HÜCKEL values of the COULOMB and resonance integrals α0 and β0 of the free ions could be measured. They turn out to depend strongly on the sign of the excess charge. The measurements of the splitting constants indicate that the COLPA-BOLTON equation possibly overestimates charge effects on the σ-system at the expense of influences from non-neighbouring 2pz-AO’s. In the case of alternant radical ions the HÜCKEL MO’s are better than those derived by MCLACHLAN’S theory, though qualitatively McLACHLAN’S theory predicts negative spin densities correctly. The g-factor measurements, which are accurate within 2 ppm, confirm the linear relation between Δg and the HÜCKEL coefficient m0 of the lowest halfoccupied π-orbital recently deduced by STONE. On the other hand neutral odd-AH-radicals have g-factors about 4 · 10-5 smaller than the theoretical values for m0=0. A linear dependence has been found between Δg and the half-wave potential U½ which provides the possibility to measure g-factors with an accuracy of about 10 ppm by measuring U½-values. This method enables one to measure g-factors even for those AH-radical ions which could not yet be detected by EPR.

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