The Mode of Reaction of 0- Radical with Aromatic Systems1

The rate constants for reaction of O- with a number of substituted benzenes and toluenes have been measured. While the values for abstraction from the methyl group of the toluenes (k - 109 M-1 sec-1) are considerably greater than for addition to the ring (k < 108 M-1 sec-') they are not strongly influenced by additional substitution. The dependence of rate constants on the substituents indicates that O- is less electrophilic than is OH. The reaction of O- with phenols and anilines is also quite rapid (kI 109 M-1 sec-1), indicating that in these cases reaction takes place via electron transfer and not addition.