6-CO-ORDINATE AND 7-CO-ORDINATE COMPLEXES OF MOLYBDENUM(II) AND TUNGSTEN(II) WITH THIOETHER LIGANDS - CRYSTAL-STRUCTURES OF [WI2(CO)3(4-MEC6H4S(CH2)2SC6H4ME-4)] AND [WI2(CO)2(MES(CH2)2S(CH2)2SME-S,S',S'')]

Reaction of [MI2(CO)3(NCMe)2] (M = Mo or W) with a slight excess of RS(CH2)2SR (R = Ph, 4-MeC6H4 or 4-FC6H4) in CHCl2 at room temperature gave [MI2(CO)3{RS(CH2)2SR}]. The molecular structure of [WI2(CO)3{4- MeC6H4S(CH2)2SC6H4Me-4}] has been determined by X-ray crystallography. It shows that the tungsten has essentially capped-octahedral geometry with a carbonyl ligand in the unique capping position. Low-temperature C-13 NMR studies on the tungsten complexes suggest that their structures in solution are similar to the solid-state structure found. Reaction of [WI2(CO)3(NCMe)2] with 2 equivalents of PhS(CH2)2SPh in CH2CL2 afforded [WI(CO)3{PhS(CH2)2SPh-S}{PhS(CH2)2SPh-S,S'}]I which was reduced by LiBu(N) to cis-[W(CO)2{PhS(CH2)2SPh-S,S'}2]. Equimolar quantities of [ML2(CO)3(NCMe)2] (M = Mo or W) and MeS(CH2)2S(CH2)2SMe reacted in CH2CL2 to give [Mol2(CO)2{MeS-(CH2)2S(CH2)2SMe-S,S',S''}] and [WI2(CO)3{MeS(CH2)2S(CH2)2SMe-S,S'}]. The latter was converted in CHCL into [WI2(CO)2{MeS(CH2)S(CH2)2SMe-S,S',S''}], the molecular structure of which is essentially a capped octahedron with a carbonyl ligand in the unique capping position.