REACTIVITY OF TUNGSTEN(V) MONONUCLEAR COMPLEXES TOWARDS LI(TCNQ) AND TCNQ - COMPARISON OF THE CRYSTAL-STRUCTURES OF [W(S2CNME2)(4)][TCNQ] AND [MO(S2CNME2)(4)][TCNQ]CENTER-DOT-MECN (TCNQ = 7,7,8,8-TETRACYANOQUINODIMETHANE)

The reaction of tungsten(v) complexes [W(S2CNR2)(4)]I (R = Me or Et) w ith Li(TCNQ) in a dimethylformamide-water mixture at room temperature afforded the new derivatives [W(S2CNR2)(4)][TCNQ] 1a and 1b (TCNQ = 7, 7,8,8-tetracyanoquinodimethane). These compounds reacted further with TCNQ in acetonitrile to produce [W(S2CNR2)(4)][TCNQ](2) in which the T CNQ moieties are in a mixed-valence state. The physical properties of these new derivatives in solution and in the solid state are presented , The structures of 1a and of its molybdenum analogue [Mo(S2CNR2)(4)][ TCNQ]. MeCN 2a have been studied by X-ray diffraction analyses: in 1a the TCNQ moieties form alternating stacks along the c axis according t o a quite unusual bond-bond overlap; in 2a the TCNQ(.-) moieties are d imerized and exhibit the usual slipped conformation.