Syntheses of new electron donors with hydroxymethyl groups and studies on their cation-radical salts

New electron donors 4,5-ethylenedithio-4′,5′-(1-hydroxypropane-2,3-diyldithio)tetrathiafulvalene (1a), 4,5-bis(methylthio)-4′,5′-(1-hydroxypropane-2,3-diyldithio)tetrathiafulvalene (1b), 4,5-ethylenedithio-4′,5′-(1,4-dihydroxybutane-2,3-diyldithio)tetrathiafulvalene (1c) and 4,5-bis(methylthio)-4′,5′-(1,4-dihydroxybutane-2,3-diyldithio)tetrathiafulvalene (1d) with hydroxymethyl groups were synthesized and characterized spectroscopically. Their redox potentials were determined using cyclic voltammetry. Crystals of cation-radical salts based on these new electron donors, (1a)2·ClO4, (1c)2·Cl, (1c)2·I, were obtained by standard electrochemical methods. The crystal structure of (1c)2·Cl was determined and studied. Electrical measurements of the cation-radical salts indicated that they displayed semiconducting behaviors, however, with good conductivities at room temperature: 0.68 S cm−1 for (1a)2·ClO4 and 0.10 S cm−1 for (1c)2·Cl.