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)

摘要

The reaction of tungsten(v) complexes [W(S2CNR2)(4)]I (R = Me or Et) with 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 TCNQ 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 to a quite unusual bond-bond overlap; in 2a the TCNQ(.-) moieties are dimerized and exhibit the usual slipped conformation. [References: 53]