Crystal structures and physical properties of BEDT-TTF charge transfer salts with (Mo 6 Cl 8 )X 2- 6 anions (BEDT-TTF = bis(ethylenedithio)-tetrathiafulvalene; X=Cl, Br)

Abstract

The crystal structures of three charge transfer salts of BEDT-TTF (bis(ethyl-enedithio)tetrathiafulvalene) with metal cluster anions [Mo6Cl8]X2-6 (X = Cl, Br) are reported, together with their electrical conductivity and magnetic properties. g4[Mo6Cl8]Br6-2THF is triclinic P1, a 9.690(2), b 12.540(5), c A, n 92.89(2)°, Z = 1 and isostructural with the corresponding X = Cl salt. Both salts show metal-insulator transitions, at 190 and 265 K, respectively. (BEDT-TTF)4[Mo6Cl8]Cl6.2CH2Cl2 is triclinic P1, a 10.290(1), b 12.877(1), c 18.024(3) A, n 91.50(1)°, Z = 1 and likewise undergoes a metal-insulator transition, at 60 K. Though the BEDT-TTF packing mode is also g , the symmetry of the stacks is different. f -(BEDT TTF)4[Mo6Cl8]Cl6.2DMF is monoclinic P21/n, a 9.676(9), b 10.20(1), c 43.37(5)°, Z =2. It is semiconducting due to charge localization within the BEDT-TTF layer.