SYNTHESIS AND PHYSICAL-PROPERTIES OF A NOVEL, HIGHLY TUNABLE FAMILY OF ORGANIC SUPERCONDUCTORS - (ET)(2)M(CF3)(4)(1,1,2-TRIHALOETHANE) (M=CU,AG,AU)

Electrocrystallization of the bis(ethylenedithio)tetrathiafulvalene (E T) electron donor molecule with the novel M(CF3)(4)(-) (M = Cu, Ag, an d Au) anions in a variety of 1,1,2-trihaloethane solvents has led to t he discovery of a remarkable series of 21 organic superconductors. The se (ET)(2)M(CF3)(4)(1,1,2-trihaloethane) salts occur in two structural modifications of the kappa-type packing motif. Crystals of the plate- like morphology have superconducting transition temperatures in the ra nge 2 - 5.8 K (low T-c phase, kappa(L)), while the transitions of the needle-like morphology are in the range 9.2 - 11.1 K (high T-c phase, kappa(H)).