Radical ions of dithieno[3,4b; 3′, 4′-e]paradithiin1,3,5,7-tetraone. Hyperfine structure from 13C, 17O, and 33S isotopes in natural abundance

Abstract

ESR studies of the radical anion and the radical cation produced from dithieno[3,4-b; 3′,4′-e]paradithin-1,3,5,7-tetraone (DPT) are reported. Satellite lines of extremely low intensity, such as those arising from radical ions which contain 17O or both 33S and 13C isotopes in natural abundance, have been detected. Extensive use has been made of the linewidth effect to determine the signs of the 13C, 33S, and 17O coupling constants. As expected on structural grounds, and predicted by a simple MO model of DPT, the π-spin populations in the radical ions DPT· ⊖ and DPT· ⊕ are to a large extent localized on the electron acceptor and donor moieties of the molecule, respectively.