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, (1)H, (13)C{(1)H}, and (125)Te 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 Na(2)S(2)O(5) affords labile tellurides, which decompose quickly even at room temperature into the more stable symmetric ditellurides, Ar(2)Te(2). Mesityl fragments bearing organotellurium(iv) derivatives show separate (1)H and (13)C{(1)H} 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.