Intramolecular Spin-Spin Exchange in Cation Radicals of Tetrathiafulvalene Derivatives Substituted with Imino Pyrolidine- and Piperidine-1-oxyls

The ESR spectra of tetrathiafulvalene (TTF) derivatives substituted with imino pyrolidine- and piperidine-1-oxyls and their cation radicals were investigated. For the neutral TTF’s the unpaired electron is localized at the nitroxide group. While, an intramolecular spin-spin exchange albeit weak occurs between the TTF cation radical and the nitroxide radical in the one-electron oxidized TTF’s, and the ground spin state of the biradical is a singlet.