Synthesis, structure, and properties of sulfido-bridged dinuclear tungsten(V) complex of dithiolene, (Pr 4N) 2[W 2(μ-S) 2{S 2C 2(CO 2Et) 2} 4

Abstract

The reaction of tetrathiotungstate (WS 4 2−) with diethyl acetylenedicarboxylate, EtO 2CCCCO 2Et, in the presence of dinuclear Pt(III) complex [Pt 2Cl 2(5-mpyt) 4] (5-mpyt=5-methylpyridine-2-thiolato) as an oxidant gave a sulfido-bridged dinuclear tungsten(V) complex of dithiolene, (Pr 4N) 2[W 2(μ-S) 2{S 2C 2(CO 2Et) 2} 4] ( 1). The absence of an appropriate oxidant in the reaction system afforded tris(dithiolene) complex (Pr 4N) 2[W{S 2C 2(CO 2Et) 2} 3] ( 2). The complex 1 was characterized structurally and spectroscopically. The complex anion in 1 has an edge-shared bioctahedral structure with two bridging sulfide ions, WW distance being 2.9425(7) Å. The fluxionality of the dithiolene ligand was observed by 1H-NMR even at −50°C for 1.