SYNTHESIS AND PROPERTIES OF OLIGOTHIOPHENE CATION-RADICAL SALTS

Oligothiophene cation radical salts were first prepared by the electro chemical oxidation method employing large-sized anions PF6-, AsF6-, Ta F6-, BF4- and GaCl4-. Several large-sized anions (AsF6-,TaF6- and GaCl 4-) gave black-needle crystalline salts. All the salts showed semicond uctive behavior with the electrical conductivities of 10(-4)-10(-6) S/ cm. Electrical conductivity and spectroscopic measurements on the cati on radical salts have suggested that oligothiophene moiety in the pres ent salts is highly oxidized, as in oligothiophene doped with nitrosyl salt.