EPR studies on carboxylic esters. Part 20. EPR spectra and spin densities in radical anions of isocoumarin, benzocoumarin and their sulfur analogues

The radical anions of isocoumarin, benzocoumarin and the six corresponding sulfur analogues have been generated by internal electroreduction and studied by EPR spectrosopy. The spin density distributions have been evaluated from the proton hyperfine structure coupling constants and by MO calculations. They are discussed with respect to the spin density distributions in related radical anions.