Six-co-ordinate 1,2-dithiolene complexes of tungsten(II) of the type [W(S-S)(CO)(2)L-2] [S-S=C3S5, benzene-1,2-dithiolate or maleonitriledithiolate; L-2=(PPh3)(2), (PEt3)(2) or Ph2P(CH2)(2)PPh2]

Reaction of the complexes [WI2(CO)(3)L-2][L-2 = (PEt3)(2), (PPh3)(2) or Ph2P(CH2)(2)PPh2 = dppe] with 1 equivalent of Na-2[S-S] (S-S = C3S5 or maleonitriledithiolate) or H(2)bdt (benzene-1,2-dithiol) in acetonitrile and ethanol at room temperature afforded good yields of the six-co-ordinate compounds [W(S-S)(CO)(2)L-2] by displacement of the iodide ligands and a carbonyl ligand. X-Ray crystallographic studies were carried out on [W(S-S)(CO)(2)L-2][S-S = C3S5, L-2 = (PEt3)(2); S-S = bdt, L-2 = (PEt3), or L-2 = dppe]. The three structures are all six-co-ordinate with geometries intermediate between octahedral and trigonal prismatic but closer to the latter.