Preparation and Structure of Bis-μ-(Benzene-1,2-Dithiolato)-bis[(benzene-1,2-dithiolato)-technetium( IV)]-Chloroform (1:1)

Abstract

After reaction of benzene-1,2-dithiol (bdtH₂) with ammonium [⁹⁹Tc] pertechnetate in aqueous alcohol, extraction of the reaction mixture with chloroform yielded wine-red crystals of the title compound, C₂₄H₁₆S₈Tc₂.CHCl₃. The crystal structure of the binuclear complex has been determined by X-ray diffraction. Crystals are triclinic and belong to the space group Pī with a 8.534(1), b 8.842(2), c 11.192(3)Ǻ, α 107.02(2), β 98.13(1), γ 100.60(2)° with Z 1. Refinement on 1524 data measured with Cu Kα radiation converged at R 0.082. The complex has exact C_i point symmetry and pseudo-C₂ symmetry. Each technetium atom is coordinated to a trigonal -prismatic array of six sulfur ligand atoms. These arrays are fused through a quadrilateral face defined by the four bridging sulfur atoms of two benzene-1,2- dithiolato ligands to give a Tc₂S₈ core of D_2h pseudo-symmetry. As a Tc - Tc bond [bond length 2.591(3)Ǻ] passes through the mid point of the quadrilateral face, this novel geometry can be described in terms of capped trigonal prisms. The chloroform is disordered.