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)₂TeCl₂ ( 1 ), (n‐C₃H₇)₂TeCl₂ ( 2 ), (i‐C₃H₇)₂TeCl₂ ( 3 ) and (c‐C₆H₁₁)₂TeCl₂ ( 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)₂Te and (n‐C₃H₇)₂Te with excess bromine gave the dialkyltellurium(IV) dibromides (C₂H₅)₂TeBr₂ ( 5 ) and (n‐C₃H₇)₂TeBr₂ ( 6 ), whereas (i‐C₃H₇)₂Te and (c‐C₆H₁₁)₂Te 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.