SYNTHESES, STRUCTURES AND ELECTRICAL-PROPERTIES OF CATION-RADICAL SALTS BASED ON TTF DERIVATIVES CONTAINING O, S AND SE

Some chemical modifications of TTF-based donor molecules are described . (TMET-STF)(2)Au(CN)(2) is isostructural with the Bechgaard salt and has a quasi one-dimensional electronic structure. We have investigated the pressure effect on the electric resistivity. The metal-insulator transition at 18 K is easily suppressed under pressure (> ca. 2.9 kbar ). At ambient pressure, the low-temperature X-ray crystal analyses dow n to 10 K indicate an enhancement of one-dimensional character. GaCl2 and FeCl4 salts of TOST are metallic down to 42 K and have the kappa-t ype structure. The AuBr2 salt of SO is metallic down to 1.5 K and isos tructural with beta ''-(BEDT-TTF)(2)AuBr2.