Technetium(I) Carbonyl Dithiocarbamates and Xanthates

Technetium(I) tetracarbonyl complexes with diethyldithiocarbamate and methylxanthate ligands [TcL(CO)₄] (L = S₂CNEt₂ and S₂COMe) were prepared. Conditions required for the formation of these complexes were found. The crystal and molecular structure of the xanthate complex was determined by single-crystal X-ray diffraction. [Tc(S₂CNEt₂)(CO)₄] undergoes decarbonylation both in solution and in the course of vacuum sublimation with the formation of a dimer [Tc(S₂CNEt₂)(CO)₃]₂ whose structure was determined by single-crystal X-ray diffraction. In donor solvents, [Tc(S₂CNEt₂)(CO)₄] and [Tc(S₂COMe)(CO)₄] undergo decarbonylation with the formation of tricarbonyl solvates [TcL(CO)₃(Sol)]. The crystal structure of the pyridine solvate [Tc(S₂CNEt₂)(CO)₃(py)], chosen as an example, was determined by single-crystal X-ray diffraction. The possibility of using bidentate S-donor acidic ligands for tethering the tetracarbonyltechnetium fragment to biomolecules was examined.