TECHNETIUM COMPLEXES WITH THIOETHER LIGANDS

In this paper we report on the synthesis, characterization and structure of new types of technetium complexes with open-chain and cyclic thioether ligands. Oxotechnetium(V) complexes of the formula [TcO(''S2'')-Cl-2]O-2 and [TcO(''S-2-O-'')Cl-2] containing single bonded oxygen in trans position to the Tc=O core, are formed with bidentate thioethers (''S-2'') and TcOCl4- as a precursor. Cationic nitridotechnetium(V) complexes of the general formulation [TcNCl(thiacrown)](+) have been obtained by ligand exchange reaction of thiacrown ethers with TcNCl4-. Cationic Tc(III) complexes [Tc(''S-4'')(SR')(2)](+) were prepared by reduction of Tc-99-pertechnetate in the presence of both a tetradentate thioether (''S-4'') and a monodentate thiol (R'-SH). Tc(III) is centred in a heavily distorted octahedron with the thiolate ligands being coordinated in cis-confrguration. The combination of tetrathiaalkanes with monodentate thiolate ligands gives full scope for structural alterations in tracer design.