Synthesis, crystal structure and electrochemistry of a new bimetallic nickel dithiolene complex (NBu4+)2{C2S4[NiS2C2S2(CO)]2}2−. A precursor for molecular conductors

The bimetallic complex (NBu4 +)2{C2S4[NiS2C2S2(CO)]2}2− has been prepared and its X-ray crystal structure has been determined. The anions are packed in layers parallel to the crystallographic (0 1 0) plane and are intermingled with parallel layers of closely packed cations. The geometry of the C2S4 (tetrathiooxalate, tto) moiety in the title compound is intermediate between that in tto4− and tto2− systems. The solution electrochemistry reveals the reversible formation of the monoanionic species and the irreversible formation of the neutral species (or a species possessing a nonintegral oxidation state). Conducting salts have been obtained by complexation of the title anion with tetrathiafulvalene (TTF) and bis(ethylenedithio)–TTF (BEDT–TTF).