Aryloxy-radicals. Part VI. Measurement of the electron spin resonance spectra of short-lived substituted phenoxy-radicals in benzene solution

Abstract

The e.s.r. spectra of short-lived alkyl- and alkoxy-substituted phenoxy-radicals can be obtained by flowing benzene solutions of the corresponding phenols through a bed of either silver oxide or lead dioxide placed within the cavity of an e.s.r. spectrometer. The hyperfine coupling constants of radicals obtained from 4-, 2,4-, and 2,4,6-substituted phenols have distinctly different values when measured in benzene and not in water, but this is not the case with 2,6-substituted phenoxy-radicals. By stopping the flow, e.s.r. spectra of secondary radicals can often be obtained; their structures receive comment.