Synthesis and redox properties of largely π-extended p-quinodimethane analogues of tetrathiafulvalene

The highest known π-extended tetrathiafulvalene (TTF) analogues with a quinoid structure are reported; the cyclic voltammetry data reveal their strong donor character involving a two-electron oxidation wave to the dication when two dithiole rings are present in the molecule. A strong donor molecule bearing only a dithiole unit has been prepared from benz[g]anthrone by a Wittig-Horner reaction and its electrochemical data reveal the presence of two one-electron oxidation waves to form the radical cation and dication; charge transfer complexes are formed in the presence of electron acceptors showing a mixed valence character.