Crystal Structure and Electronic Properties of an Organic Ion-Radical Salt: 3,3'-Diethyl-4,4'-Dimethyl-2,2'-Thiazolocyanine-[TCNQ]2

An organic ion-radical salt, 3,3'-diethyl-4,4'-dimethyl-2,2'-thiazolocyanine-[TCNQ] 2 , is synthesized and its crystal structure and electronic properties are investigated. The salt forms triclinic crystal in the space group P \bar1 with a =13.153(4), b =18.314(5), c =7.792(2) A, α=107.21(3), β=103.60(4), γ=77.75(3)° and Z =2. The electric conduction of single crystals is anisotropic and shows semiconductive temperature dependence. The intrinsic spin-susceptibility of the salt shows a broad maximum around 265 K and decreases to zero below 15 K. A single ESR absorption is observed for a single crystal and its linewidth strongly depends on the temperature and the direction of external magnetic field. These electronic properties are discussed on the basis of the peculiar crystal structure of the salt.