Synthesis and Structure of [PPh4]3[Cr(Te4)3]·DMF:  The First Tris(tetratelluride) Complex

The compound [PPh4]3[Cr(Te4)3]·DMF has been synthesized from the reaction of Cr(CO)6 with a polytelluride solution in dimethylformamide at 100 °C. The compound has been characterized by 125Te NMR and single-crystal X-ray diffraction techniques. The compound crystallizes in the triclinic space group P1̄, with a = 12.991(3) Å, b = 14.782(3) Å, c = 24.628(5) Å, α = 90.63(3)°, β = 104.45(3)°, γ = 106.49(3)°, and Z = 2 (T = 153 K). The [Cr(Te4)3]3- anion consists of a Cr(III) center chelated by three Te4 2- ligands in a distorted octahedral environment. The anion has the Δλλλ (or Λδδδ) conformation.