A Trigonal-Prismatic Hexanuclear Technetium(II) Bromide Cluster: Solid-State Synthesis and Crystallographic and Electronic Structure

The compound Na­{[Tc6Br12]2Br} has been obtained from the decomposition of TcBr4 under vacuum in a Pyrex ampule at 450 °C. The stoichiometry of the compound has been confirmed by energy-dispersive X-ray spectroscopy and its structure determined by single-crystal X-ray diffraction. The compound contains a trigonal-prismatic hexanuclear [Tc6Br12] cluster. The cluster is composed of two triangular Tc3Br6 units linked by multiple Tc–Tc bonds. In the Tc3Br6 unit, the average Tc–Tc distance [2.6845(5) Å] is characteristic of Tc–Tc single bonds, while the average Tc–Tc distance between the two triangular units [2.1735(5) Å] is characteristic of TcTc triple bonds. The electronic structure of the [Tc6Br12] cluster was studied by first-principles calculations, which confirm the presence of single and triple Tc–Tc bonds in the cluster.