Fluorine Hyperfine Interaction in Aromatic Anion Radicals

1969 ◽  
Vol 24 (12) ◽  
pp. 1980-1988 ◽  
Author(s):  
J.P. Colpa ◽  
P. H. H. Fischer
Keyword(s):  
Hyperfine Interaction ◽  
Theoretical Estimate ◽  
Aromatic Radicals ◽  
Hyperfine Splittings ◽  
Two Parameters ◽  
Q Factors ◽  
Spin Densities ◽  
Anion Radicals

The relation between the fluorine hyperfine splittings in about 20 fluorine substituted aromatic radicals and the π spin densities calculated according to McLachlans method is analysed with an expression of the type aF = QFFF ρπFF + QFCC ρπCC + (QFFC + QFFC) ρπFC . For the Q factors the following values are obtained: QFFF =931 gauss; QFCC =86.6 gauss and (QFFC + QFFC) =345 gauss. Two simpler expressions with one and two parameters respectively are also tested. A theoretical estimate is made for the values of the Q factors and the results are compared with the values obtained semi-empirically.

THE ELECTRON SPIN RESONANCE SPECTRA OF THE POSITIVE AND NEGATIVE IONS OF DIPHENYLENE

1960 ◽  
Vol 38 (4) ◽  
pp. 503-507 ◽  
Author(s):  
C. A. McDowell ◽  
J. R. Rowlands
Keyword(s):  
Electron Spin Resonance ◽  
Hyperfine Interaction ◽  
Electron Spin ◽  
Negative Ions ◽  
Negative Ion ◽  
Spin Resonance ◽  
Hyperfine Splittings ◽  
Positive Ion

The electron spin resonance spectra of the positive and negative ions of diphenylene have been measured. It has been found that these spectra consist of five lines showing that the observed hyperfine interaction is caused by four equivalent protons. The over-all extent of the positive ion spectrum is 18 gauss compared with that of 12.9 gauss for the negative ion. The hyperfine splittings observed are 4.0 gauss and 2.75 gauss respectively.

Negative Spin Densities in Aromatic Radicals

1957 ◽  
Vol 27 (4) ◽  
pp. 984-985 ◽  
Author(s):  
Harden M. McConnell ◽  
Donald B. Chesnut
Keyword(s):  
Aromatic Radicals ◽  
Spin Densities

Isotropic hyperfine interaction with the fluorine nuclei in fluorinated aromatic radicals

1970 ◽  
Vol 10 (6) ◽  
pp. 885-891 ◽  
Author(s):  
P. V. Schastnev ◽  
G. M. Zhidomirov ◽  
N. D. Chuvylkin
Keyword(s):  
Hyperfine Interaction ◽  
Aromatic Radicals ◽  
Isotropic Hyperfine Interaction

On the Relations between ESR-Hyperfine Splittings and Spin Densities in Simple Substituted Alkyl Radicals

1965 ◽  
Vol 20 (3) ◽  
pp. 428-432
Author(s):  
Hanns Fischer
Keyword(s):  
Coupling Constants ◽  
Product Rule ◽  
Alkyl Radicals ◽  
Simple Treatment ◽  
Hyperfine Splittings ◽  
Spin Densities

A simple treatment of spin densities and ESR-coupling constants of substituted alkylradicals is developed. It is shown that the spin densities ρa in the α-carbon 2 pz-functions may be calculated by use of a product rule from substituent parameters 1 (Xi). Furtheron it is found, that the parameters Q in the well known relations a = Q-ρa are unique constants for rotating methylgroups, whereas for α-protons they depend on the electron withdrawing forces of the substituents.Values of Δ (Xi) and QHHCH are tabulated and discussed. The ESR-coupling constants of four new transient alkyl radicals are also given.

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