Synthesis and characterization of carbonyl functionalized organotellurium(iv) derivatives

The current study focuses on synthesis and characterization of carbonyl functionalized unsymmetrical diorganotellurium(iv) dichlorides (1-5), dibromide (6), and their characterization by elemental analysis, ¹H, ¹³C{¹H}, and ¹²⁵Te NMR spectroscopy. In addition to this, compounds 1, 4 and 5 were further confirmed via single-crystal X-ray studies. Reduction of all the dichlorides with Na₂S₂O₅ affords labile tellurides, which decompose quickly even at room temperature into the more stable symmetric ditellurides, Ar₂Te₂. Mesityl fragments bearing organotellurium(iv) derivatives show separate ¹H and ¹³C{¹H} NMR signals for the ortho methyls and meta protons of the mesityl ring. Among the Te(iv) dichlorides, the observed O-H⋯O, C-H⋯O, C-H⋯Cl, Te⋯O and Te⋯Cl hydrogen and secondary bonding interactions are longer than Σr _cov (sum of the covalent bond radii) and significantly shorter than Σr _vdw (sum of the van der Waal radii) respectively. The linearity of the C-Te⋯O, C-H⋯O and C-H⋯Cl makes n → σ* orbital interaction possible.