Electron Spin Resonance Studies of Thiocarbonyl Anion Radicals

Abstract

The temperature dependence of the e.s.r. spectra of a series of sodium reduced thiones is reported. The thioketyls thiobenzophenone, p,p′-dimethoxythiobenzophenone, xanthene-9-thione, thioxanthene-9-thione, and their ketone analogues have been studied. Several show temperature-dependent sodium hyperfine structure near room temperature, but dissociate at lower temperatures to give spectra of thioketyl anions with no sodium coupling and markedly different g-values. Ring proton hyperfine splittings are found to be independent of the ion pairing process and independent of temperature. Models of ion pairing are discussed. Comparison is made to uhf–scf–mo calculations.