Rate constants for the reactions of cyclohexadienyl type radicals with quinones

Observation of substituted cyclohexadienyl type radicals by muon spin rotation in substituted benzene at different concentrations of added p-benzoquinone or duroquinone allows a selective determination of rate constants for the reaction of the radicals with oxidants. Methyl substitution has no effect, methoxy substitution enhances the rate constants for the ortho and para substituted isomers.Support by the Swiss National Foundation for Scientific Research, by the Swiss Institute for Nuclear Research (SIN), the Netherlands Organisation for the Advencement of Pure Research (Z.W.O.) and the Foundation for Fundamental Research on Matter (F.O.M.) are gratefully acknowledged.