Electron spin resonance of fluorine-substituted 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