TECHNETIUM AND RHENIUM COMPLEXES WITH THIOETHER LIGANDS .4. SYNTHESISAND STRUCTURAL CHARACTERIZATION OF BINUCLEAR OXORHENIUM(V) COMPLEXES WITH BIDENTATE THIOETHER COORDINATION

Binuclear oxorhenium(V) complexes, [ReO(''S-2'')Cl-2]O-2, have been pr epared by reduction of ReO4- with SnCl2 in strongly acidic solution an d in the presence of aliphatic thioethers of the general formula R-CH2 CH2-S-CH2CH2-S-CH2CH2-R' (''S-2''; R, R' = H, Et; R = S-Bu, R' = Et; R = O-Et, R' = H; R, R' = O-Et). Alternatively the compounds can be obt ained by ligand exchange reactions starting from [ReOCl4](-) in methan olic solution. A representative derived from 5,8-dithiadodecane (R,R' = Et) has been studied by X-ray diffraction. The complex consists of t wo independent [ReO(''S-2'')Cl-2] units bridged by an oxygen atom. Eac h rhenium atom is centred in a distorted octahedron with the equatoria l plane formed by the S2Cl2 donor set. The sulphur and chlorine atoms of the units are in the anti position with respect to the bridging oxy gen.