Physical and Structural Properties of a New Series of Radical-Cation Salts Based on the Tetraselenafulvalene Backbone: DMtTSeF2 – X

Abstract
We have synthetized and purified the dimethyltrime-thylene tetraselenafulvalene (DMtTSeF). From this unsymmetrical molecule a series of radical cation salts has been prepared by electro-oxidation. This new series, isostoicheiometric and isomorphous with the TMTSeF salts, exhibits a metallic behavior down to 0,1 K without any sign of either a metal-insulator or a superconducting phase transition.