Electron spin resonance of fluorine-substituted nitro-aromatic anion radicals

1968 ◽  
Vol 46 (24) ◽  
pp. 3847-3856 ◽  
Author(s):  
P. H. H. Fischer ◽  
H. Zimmermann
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Half Life ◽  
Coupling Constants ◽  
Acetonitrile Solution ◽  
Spin Resonance ◽  
Related Compounds ◽  
Nitro Benzene ◽  
Nitro Aromatic ◽  
Anion Radicals

Electron spin resonance spectra have been observed for anion radicals derived from 2-fluoro-nitro-benzene, 3-fluoro-nitrobenzene, 2,4-difluoro-nitrobenzene, 2,5-difluoro-nitrobenzene, 4-fluoro-2-nitro-phenol, 2-fluoro-6-nitrophenol, and 3-fluoro-6-nitrophenol. All radicals were generated electrolytically in dimethoxyethane/acetonitrile solution, acetonitrile, or dimethylformamide. The radicals are generally quite stable with the exception of those from 2-fluoro-6-nitrophenol and 3-fluoro-6-nitrophenol, the latter decaying with a half-life of approximately 6 min. All spectra can be interpreted completely, and coupling constants are assigned by comparison to related compounds and consistency arguments.

A PARAMAGNETIC RESONANCE STUDY OF HINDERED DIARYLMETHYL RADICALS AND RELATED COMPOUNDS: I. ANALYSIS OF THE SPECTRA

1966 ◽  
Vol 44 (12) ◽  
pp. 1387-1395 ◽  
Author(s):  
H. R. Falle ◽  
F. C. Adam
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Ion Pair ◽  
Coupling Constants ◽  
Methyl Groups ◽  
Steric Repulsion ◽  
Paramagnetic Resonance ◽  
Spin Resonance ◽  
Phenyl Rings ◽  
Related Compounds

Several ortho-substituted radicals of the benzhydryl type and a variety of diaryl ketyls have been studied through the nuclear hyperfine structure of their electron spin resonance spectra. A strong similarity is found between the spectra of a given ketyl and its hydrocarbon analogue. This suggests that when ketones are reduced, a very tight ion pair is formed between the ketyl anion and its cation. Although the coupling constants of the protons vary with different reducing agents, larger variations are observed when bulky groups are substituted into ortho positions. These larger changes are attributed to a forced internal rotation of the phenyl rings. The distortion results from the steric repulsion between the ortho groups. The effect of 'buttressing' of ortho methyl groups is also studied. Deuterium and 13C substitutions have been effected in some of the compounds.

THE ELECTRON SPIN RESONANCE SPECTRA OF DINITRONAPHTHALENE ANION RADICALS

1965 ◽  
Vol 43 (12) ◽  
pp. 3400-3406 ◽  
Author(s):  
P. H. H. Fischer ◽  
C. A. McDowell
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Coupling Constants ◽  
Radical Anions ◽  
Proton Coupling ◽  
Spin Resonance ◽  
Full Symmetry ◽  
Nitrogen Coupling ◽  
Anion Radicals

The radical anions of 1,4-dinitronaphthalene, 1,5-dinitronaphthalene, and 1,8-dinitronaphthalene have been generated by electrolytic means, and their e.s.r. spectra recorded. The spectra consist of 61, 111, and 85 lines respectively, and can be analyzed in terms of one nitrogen and three proton coupling constants, consistent with the full symmetry of the species giving rise to them. These constants are, for 1,4-dinitronaphthalene: aN = 0.97 G, aH2 = 1.69 G, aH5 = 0.53 G, and aH6 = 0.41 G; for 1,5-dinitronaphthalene: aN = 2.30 G, aH2 = 2.42 G, aH3 = 0.44 G, and aH4 = 2.82 G; for 1,8-dinitronaphthalene: aN = 3.03 G, aH2 = 3.63 G, aH3 = 0.95 G, and aH4 = 3.73 G. Whereas the nitrogen coupling constants can be unambiguously assigned, this, in the absence of deuteration studies say, is not the case for the three sets of equivalent protons. As an aid in the assignment of proton coupling constants, Hückel LCAO calculations and simplified SCFMO calculations by the method of McLachlan have been performed. The first mentioned of the above proton constants could thus be assigned with reasonable certainty, the remaining two aHi remain ambiguous.

Electron spin resonance studies of several anion radicals of nitro-substituted thioacylpiperidines and morpholines

1982 ◽  
Vol 20 (4) ◽  
pp. 217-221 ◽  
Author(s):  
C. Cercasov ◽  
F. Cornea ◽  
M. Ciureanu ◽  
M. Hillebrand ◽  
V. E. Sahini ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Spin Resonance ◽  
Anion Radicals
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