Synthesis and structure of [Co6(μ3-Se)5.18(μ3-Te)2.82(PEt3)6]·DMF

The reaction of [PPh4]3[Co3(Se4)6] with TePEt3 in dimethyformamide at 20 °C in the presence of PEt3 gives the molecular cluster [Co6(μ3-Se)5.18(μ3-Te)2.82(PEt3)6]·DMF. The cluster has been characterized by single-crystal X-ray diffraction (XRD) methods. It crystallizes with three formula units in space group of the trigonal system in a cell of dimensions at T=153 K of a=17.274(2) Å, c=19.384(4) Å, γ=120°. The cluster [Co6(μ3-Se)5.18(μ3-Te)2.82(PEt3)6]·DMF consists of an octahedron of Co atoms with all the faces symmetrically capped by μ3-Se or μ3-Te atoms and each Co atom bonded to a PEt3 group to provide a distorted square-pyramidal environment. These μ3-Se and μ3-Te atoms are disordered as are the solvate DMF molecules.