The crystal and molecular structures of the complex [99TcCl(CO)3(C5H8O2)]2 (C5H8O2 = Hacac =
acetylacetone) formed in the course of prolonged standing of a [99Tc(acac)(CO)4] solution in ССl4/CDCl3 and of
its analog containing no organic ligand, [99TcCl(CO)4]2, were determined. Both complexes contain a [Tc2(μ-Cl)2]
four-membered ring. The remaining sites in the coordination sphere of the Tc atom are occupied by carbonyl
ligands, and in the case of [99TcCl(CO)3(Hacac)]2, also by the neutral acetylacetone molecule in the enol form.
The Hacac molecules in the binuclear complex are in the cis position to the Cl atoms in the octahedral surrounding
of the Тс atoms and in the trans position to each other relative to the [Tc2(μ-Cl)2] ring. A comparative analysis of
the geometries of the complexes and their known analogs was performed.