Carbon–tellurium bond cleavage in tellurolatochromium complexes. Synthesis and single-crystal structures of [Cr4(cp)4TenO4–n](cp =η5-C5H5, n= 1–3)

Abstract

The exhaustive thermolysis of [Cr(cp)(CO)₃(TePh)](cp =η⁵-C₅H₅) in toluene for 48 h at 80 °C led to the isolation of [Cr₄(cp)₄ Te₇](ca. 24%), [Cr₄(cp)₄Te₃O](14.4%), [Cr₄(cp)₄Te₂O₂](37.2%) and [Cr₄(cp)₄TeO₃] in minute amounts. Thin-layer chromatography and proton NMR spectral monitoring showed the formation of [Cr₄(cp)₄Te₃O] and [Cr₄(cp)₄Te₂O₂] from the intermediate [{Cr(cp)(TePh)}₂Te]. Under thermolytic conditions, [Cr₄(cp)₄Te₃O] and [Cr₄(cp)₄Te₂O₂] undergo reversible transformation with simultaneous formation of [Cr₄(cp)₄TeO₃]. The structures of three of the complexes were established by X-ray diffraction analysis.