NOVEL MOLECULAR-METALS COMPOSED OF A [3]RADIALENE TYPE ACCEPTOR - [2-(DICYANOMETHYLENE)-2,5-SELENOQUINO]CYCLOPROPANE DERIVATIVE

A new acceptor, [2-(dicyanomethylene)-2,5-selenoquino]cyclopropane der ivative (DCNS-CP) has been efficiently synthesized by the reaction of a cyclopropenone derivative with selenienylmalononitrile and subsequen t oxidation. DCNS-CP proved to be a powerful acceptor and its anion ra dical and dianion are very thermodynamically stable. Single crystals o f [TTF][DCNS-CP] and [TTT][DCNS-CP] complexes showed metallic temperat ure dependencies of the conductivities down to 182 and 80 K, recording sigma(max) values of 500 and 760 Scm(-1), respectively. These are a n ew class of metals based on a functionally different type of organic a cceptor consisting of three electron-accepting groups in full conjugat ion.