Crystal Structures, and Electrical Conducting and Magnetic Properties in the Plate Crystals of (Ethylenedithiotetrathiafulvalenoquinone-1,3-dithiolemethide)2·MX4 (M=Fe, Ga, X=Br; M=Fe, X=C1) Salts

By the reaction of a new donor molecule, ethylenedithiotetrathiafulvalenoquinone-1,3-dithiolemethide (1) with FeBr3, GaBr3 or FeCl3 in CH3CN/CS2 charge transfer (CT) salts of 1 with counteranions of FeBr4−, GaBr4− or FeCl4− (12·FeBr4, 12·GaBr4 and 12·FeCl4) as plate crystals were obtained. Their crystal structures are apparently similar to each other, in which 1 molecules are dimerized in the parallel direction of their molecular long axes, and the dimers are stacked with changing the direction of the molecular long axes alternately to form a one- dimensional column. The counteranions intervene between the 1-stacked columns and are aligned in a zigzag manner. The room-temperature electrical conductivities of 12·FeBr4 and 12·GaBr4 are fairly high (10–15 S cm−1), but a small value (0.8 S cm−1) is obtained for 12·FeCl4. For all CT salts, temperature dependences of electrical conductivity are semiconducting in spite of very small activation energies (30–90 meV). Based on the comparison between their electrical conducting and magnetic properties, it is suggested that the d spins of FeBr4− or FeCl4− ions exert almost no influence on the π conducting electrons in the 1-stacked column.