Conducting salts of the new donor bis(ethylenedithio)tetrathionaphthalene (EDNA)

All radical cation-based superconductors are derived from tetrachalcogenafulvalene precursors. Bis(ethylenedithio) tetrathionaphthalene (EDNA) was designed and synthesized as a possible alternative to this limited set of starting materials. An electrochemical study of EDNA is discussed. The first radical cation salts of EDNA are reported. A variety of EDNA:anion stoichiometries are observed. Four-probe resistivity and room temperature ESR data are presented for three (EDNA)m(X)n salts (X= ClO4, SCN, I3). (EDNA)ClO4 and (EDNA)3(SCN)2 are semiconductors, but the room temperature resistivity of the perchlorate salt is 106 greater than that of the thiocyanate salt. (EDNA)2I3 is metallic to 220 K, where it undergoes a transition to a low activation energy (Ea = 88 meV) semiconductor.