Chlorination and bromination of dialkyl tellurides

The reactions of dialkyl tellurides R2Te (R = C2H5, n-C3H7, i-C3H7, c-C6H11) with sulfuryl chloride and bromine were examined. The dialkyltellurium(IV) dichlorides (C2H5)(2)TeCl2 (1), (n-C3H7)(2)TeCl2 (2), (i-C3H7)(2)TeCl2 (3) and (C-C6H11)(2)TeCl2 (4) were obtained upon reaction with stoichiometric amounts of SO2Cl2. Excess of SO2Cl2 resulted in formation of mixtures of R2TeCl2 and RTeCl3. Treatment of (C2H5)(2)Te and (n-C3H7)(2)Te with excess bromine gave the dialkyltellurium(IV) dibromides (C2H5)(2)TeBr2 (5) and (n-C3H7)(2)TeBr2 (6), whereas (i-C3H7)(2)Te and (c-C6H11)(2)Te yielded the alkyltellurium(IV) tribromides i-C3H7TeBr3 (7) and c-C6H11TeBr3 (8). Equimolar amounts of bromine resulted in mixtures of R2Te and RTeBr3. All products were identified and characterized by analytical and spectroscopic methods. n-Propyl tellurium tribromide (9) was detected from a solution of the dibromide 6 after prolonged periods. The crystal structures of 7, 8 and 9 were determined.