Physical properties and crystal structures of MeDA-TTP salts

A dithiane analogue of MeDH-TTP [2-isopropylidene-5-(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene], MeDA-TTP [2-isopropylidene-5-(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene], has been prepared, and crystal structures and electrical properties of MeDA-TTP radical salts have been investigated. Although all the salts are isostructural, conducting behavior differs between the salt with an octahedral anion and the one with a tetrahedral anion; the salts with octahedral anions are metallic, but the ClO4 salt is semiconductive. A dithiane analogue of DODHT [(1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene], DADOT [2-(1,3-dithiane-2-ylidene)-4,5-(1,4-dioxane-2,3-diyldithio)-1,3-dithiole] has also been synthesized. Crystal structure of the DADOT salt is completely different from that of DODHT superconductors.