S. Steenken, P. O'Neill, D. Schulte‐Frohlinde
1977
Citations
0
Influential Citations
33
Citations
Journal
The Journal of Physical Chemistry
Abstract
In aqueous solution 2-, 3-, and 4-methoxybenzoic acid; 2,3-, 2,4-, 2,6-, 3,4-, and 3,5-dimethoxybenzoic acid; and 2,3,4-, 2,4,5-, 2,4,6-, and 3,4,5-trimethoxybenzoic acid react with Tl/sup 2 +/, Ag/sup 2 +/, and SO/sub 4//sup -/ by electron transfer to yield radical zwitterions. The radical zwitterions were identified using in situ radiolysis and photolysis electron spin resonance and spectrophotometric pulse radiolysis techniques. The coupling constants of the radical zwitterions are very similar to those of radical cations from structurally related methoxylated benzenes, indicating that the carboxyl group has very little influence on spin distribution. The radical zwitterions, with the exception of that from 3-methoxybenzoic acid, decay by second-order kinetics with rate constants ranging from 6 x 10/sup 4/ to 3 x 10/sup 9/ M/sup -1/ s/sup -1/, depending on the number and on the positions of the methoxyl groups relative to each other. Decarboxylation of the radical zwitterions does not occur.