Temperature Dependence of ESR Linewidths of Some Nitrobenzene Anion Radicals

Abstract
Electron spin resonance spectra of anion radicals of nitrobenzene and p-nitrobenzoic acid in dimethylformamide and of p-nitrophenol in dimethylformamide and acetonitrile have been obtained over a range of temperatures. Linewidths have been measured and the variations among them are discussed in terms of the Freed—Fraenkel theory. It is concluded that the anisotropy of molecular tumbling must be considered for these systems, but a complete analysis has not been made.