RATIONAL DESIGN OF ORGANIC SUPERCONDUCTORS THROUGH THE USE OF THE LARGE, DISCRETE MOLECULAR ANIONS M(CF3)(4)(-) (M=CU, AG, AU) AND SO3CF2CH2SF5-

A new approach to the synthesis of organic superconductors has recentl y been pioneered which involves the use of large, discrete, molecular anions as the charge-compensating entities in these charge transfer sa lts. The organic electron-donor molecule bis(ethylenedithio)tetrathiaf ulvalene (BEDT-TTF or ET) has been electrocrystallized with the novel organometallic M(CF3)(4)(-) (M = Cu, Ag, and Au) anions in a variety o f 1,1,2-trihaloethane solvents. Over twenty organic superconductors ha ve been synthesized which can be described by the general formula (ET) (2)M(CF3)(4)(1,1,2-trihaloethane). These solvated salts are shown to h ave highly anisotropic physical properties which can be tuned via modi fications of each of their three molecular components: ET electron don or molecule, M(CF3)(4)(-) anion, and neutral 1,1,2-trihaloethane solve nt molecule. Superconductivity has also been observed in an ET salt co ntaining the discrete SF5CH2CF2SO3- anion with an onset temperature ne ar 5.2 K.