Technetium(I) Carbonyl Dithiocarbamates and Xanthates

Technetium(I) tetracarbonyl complexes with diethyldithiocarbamate and methylxanthate ligands [TcL(CO)<sub>4</sub>] (L = S<sub>2</sub>CNEt<sub>2</sub> and S<sub>2</sub>COMe) 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(S<sub>2</sub>CNEt<sub>2</sub>)(CO)<sub>4</sub>] undergoes decarbonylation both in solution and in the course of vacuum sublimation with the formation of a dimer [Tc(S<sub>2</sub>CNEt<sub>2</sub>)(CO)<sub>3</sub>]<sub>2</sub> whose structure was determined by single-crystal X-ray diffraction. In donor solvents, [Tc(S<sub>2</sub>CNEt<sub>2</sub>)(CO)<sub>4</sub>] and [Tc(S<sub>2</sub>COMe)(CO)<sub>4</sub>] undergo decarbonylation with the formation of tricarbonyl solvates [TcL(CO)<sub>3</sub>(Sol)]. The crystal structure of the pyridine solvate [Tc(S<sub>2</sub>CNEt<sub>2</sub>)(CO)<sub>3</sub>(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.