Crystal structures, and electrical conduction and magnetic properties in CuCl4 salts of dimethylthio- and ethylenedithio-tetrathiafulvalenothioquinone-1,3-dithiolemethides

The reaction of dimethylthio- (1) and ethylenedithio-tetrathiafulvalenothio quinone-1,3-dithiolemethides (2) with CuCl2 afforded the corresponding CuCl 4 salts, (1)(2). CuCl4 and (2)(3). CuCl4. For (1)(2). CuCl4 the 1 molecules are stacked to form a one-dimensional column, and in each column the neigh boring 1 molecules are dimerized. On the other hand, the 2 molecules in (2) (3). CuCl4 are stacked one-dimensionally in a triad unit. The CuCl4 ions in tervene between the 1- or 2-stacked columns in each case. The electrical re sistivities (rho) for single crystals of ( 1)(2). CuCl4 and (2)(3). CuCl4 w ere 3 x 10(4) and 0.6 Omega cm at room temperature, respectively. The rho v alue of (2)(3). CuCl4 increased continuously on cooling, and its activation energy was 0.15 eV, which became gradually smaller with increasing applied pressure. For (1)(2). CuCl4 the Cu(ii) spins on the CuCl4 ions were only p resent whilst (2)(3). CuCl4 involved both conducting pi electrons on the 2- stacked column and localized Cu(ii) spins on the CuCl4 ions which did not i nteract with each other between 300 and ca. 170 K, but below ca. 170 K the conducting pi electrons disappeared, presumably as a result of interaction with the localized d spins.