SYNTHESIS, STRUCTURE AND CHARACTERIZATION OF MIXED CYCLOPENTADIENYL-DITHIOLENE METAL-COMPLEXES, [CO(ETA-C5H5)(2)][NI(C3S5)(2)](3)CENTER-DOT-2MECN AND [NI(ETA-C5H5)(C3S5)]

Two new compounds [Co(eta-C5H2)(2)][Ni(C3S5)(2)](3) . 2MeCN and [Ni(et a-C5H5)(C3S5)], both obtained by combination of the nickel complex ani on [Ni(C3S5)(2)](-) (C3S5 = 4,5-disutfanyl-1,3-dithiole-2-thionate) an d the metallocenium cation [M(eta-C5H2)(2)](+) (M = Co or Ni), respect ively, have been prepared and characterized crystallographically. The non-integral oxidation-state cobalt complex with the unusual 1:3 stoic hiometry was obtained by electrochemical oxidation of [NBu(4)][Ni(C3S5 )(2)] in the presence of [Co(eta-C5H5)(2)]PF6. It is semiconductive (s igma = 0.06 S cm(-1) at room temperature, E(a) = 0.18 eV between 300 a nd 250 K). The crystal structure shows that the asymmetric unit contai ns one Ni(C3S5)(2) unit, one Ni(C3S5) entity, one Co(eta-C5H5) unit an d one molecule of acetonitrile. The Ni(C3S5)(2) units are associated i n triads stacked along the [101] direction. No significant differences are observed in the distances and angles within the two symmetry-unre lated Ni(C3S5)(2) units, indicating that the charges of both units are very similar. The cyclopentadienyl rings are staggered due to the loc ation of the Co atoms on inversion centres. The average Co-C distance is comparable to those found in several cobaltocenium salts. The compo und [Ni(eta-C5H5)(C3S5)] was obtained unexpectedly from the reaction o f [Ni(eta-C5H5)(2)]BF4 with Na[Ni(C3S5)(2)] and characterized by mass spectrometry, conductimetry and X-ray analysis. The crystal structure shows that the asymmetric unit consists of one [Ni(eta-C5H5)(C3S5)] en tity. The C5H5 ring is disordered over two positions. The Ni(C3S5) uni t is planar and almost perpendicular to the C5H5 rings.