Synthesis and Properties of Tellurinic Anhydride–Tellurone Adducts

The synthesis and characterization of stable tellurinic anhydride–tellurone adducts are reported. Treatment of aryltellurinic anhydride with diaryl tellurone gave pentacyclotelluroxane consisting of two molecules each of the starting tellurium oxides. The bulky aromatic substituents attached to the tellurium atoms efficiently prevent further aggregation and enable full characterization using multinuclear (1H, 13C, and 125Te) NMR and IR spectroscopy as well as elemental analysis. For (TipTe)4(Tip2Te)2O10 (3TT, Tip = 2,4,6-triisopropylphenyl), the molecular structure was unambiguously determined by an X-ray crystallographic analysis. To estimate the dissociation energies of the tellurinic anhydride–tellurone adducts, density functional theory calculations were performed, and it was found that the adducts are highly stabilized by forming a four di-μ-oxo bridge structure.