Dibenz[b,f]oxepin and thiepin radical anions. Conjugative properties of sulfur in its different oxidation states

The radical anion of dibenzb,f]oxepin has been investigated by esr spectroscopy and the relative coupling constants compared with dibenzob,f]thiepin. In both cases assignments were obtained using a theoretical method (INDO). In addition radicals from dibenzob,f]thiepin sulfoxide and sulfone could be detected and, unusually, the free electron density on carbon atoms of the radical anion containing a sulfonyl group is larger than that on carbons of radical anions containing a sulfide or a sulfoxide group.