TECHNETIUM COMPLEXES WITH THIOETHER LIGANDS .2. SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NEUTRAL OXOTECHNETIUM(V) COMPLEXES WITH DITHIOETHERS - X-RAY STRUCTURE-ANALYSIS OF MU-OXO-BIS(5,8-DITHIADODECANE)DICHLOROOXOTECHNETIUM(V) AND (8-HYDROXY-3,6-DITHIAOCTAN-1-OLATO)DICHLOROOXOTECHNETIUM(V)

Neutral, bidentate thioethers such as 5,8-dithiadodecane, 3,6-dithiaoctane (''S2'') as well as the dithia-diole 1,8-dihydroxy-3,6-dithiaoctane [''S2(OH)2''] react with tetrachlorooxotechnetate (TcOCl4-) in acetone to give binuclear oxo species of the type [TcO(''S2'')Cl2]2O with dithiaalkanes and [TcO(''S2O(OH)'')Cl2] with the dithia-diole, respectively. The complexes have been characterized by elemental analysis and spectroscopic methods. The crystal structures of [TcO(5,8-dithiadodecane)Cl2]2O (1) and [TcO(8-hydroxy-3,6-dithiaoctan-1-olato)Cl2] (3) were determined from X-ray data: 1 consists of two independent [TCO(''S2'')Cl2] units bridged by an oxygen atom. Each technetium atom is centred in a distorted octahedron with the equatorial 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 oxygen. The structural analysis of 3 shows that the metal has distorted octahedral coordination, with the equatorial plane formed by the sulphur and chlorine atoms. Furthermore, one terminal oxygen is coordinated in the trans position to the Tc=O3+ core, while the second hydroxy group is non-coordinated.