Crystal Structures, and Electrical Conducting and Magnetic Properties in the Plate Crystals of (Ethylenedithiotetrathiafulvalenoquinone-1,3-dithiolemethide) 2· MX 4 ( M=Fe, Ga, X=Br; M=Fe, X=C1) Salts

Abstract

By the reaction of a new donor molecule, ethylenedithiotetrathiafulvalenoquinone-1,3-dithiolemethide (1) with FeBr 3, GaBr 3 or FeCl 3 in CH 3CN/CS 2 charge transfer (CT) salts of 1 with counteranions of FeBr 4 −, GaBr 4 − or FeCl 4 − (1 2·FeBr 4, 1 2·GaBr 4 and 1 2·FeCl 4) 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 1 2·FeBr 4 and 1 2·GaBr 4 are fairly high (10–15 S cm −1), but a small value (0.8 S cm −1) is obtained for 1 2·FeCl 4. 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 FeBr 4 − or FeCl 4 − ions exert almost no influence on the π conducting electrons in the 1-stacked column.