6-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) o r 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 acetoni trile 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 ca rried 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-or dinate with geometries intermediate between octahedral and trigonal pr ismatic but closer to the latter.