Design And Synthesis Of Organic Superconductors

The principal objectives of this work were the design, synthesis, and preliminary characterization of new organic conductors and superconductors. Electrocrystallization facilities were constructed that accommodate 96 crystal growth cells. Crystal formation takes place in a temperature-controlled (plus or minus 0.1 C). vibrationally-isolated, (vertical isolation efficiency at 10 Hz in 60-90%), inert-atmosphere environment. A variety of radical-cation salts of bis(ethylenedithio)tetraselenafulvalene were grown and characterized by crystallography, tight-binding band calculations, electronic transport, magnetic properties, and a number of other solid-state methods. Significant findings include the discovery of a tetrachlorogallate salt that is a superconductor with a transition temperature 5.5 deg higher than any previously known organic material containing selenium and magnetoresistance studies on mercury thiocyanate salts that suggest that strong electron-electron interactions are important in promoting and enhancing superconductivity in organic superconductors. A new organic conductor precursor, bis(ethylenedithio)tetrathionaphthalene, was synthesized and several of its conducting salts were investigated in a preliminary manner. Numerous collaborative studies were undertaken.