Diorgano Tellurium Mixed Dihalides

When l,3-dihydro-2-benzotellurophene 2,2-dichloride and the corresponding dibromide are dissolved in DMF, halogen exchange occurs. The rate of exchange is slow on the NMR time scale. The broadened Te-NMR signals of the dichloride and the chloride bromide were observed The equilibrium constant for this reaction was not determined. It is likely that in solution diorgano tellurium dihalides with two different halogen atoms are in equilibrium with the two symmetrical dihalides. Isolation attempts will disturb the 

The reaction of bis[trifluoromethyl] tellurium with chlorine fluoride at — 78° with fluorotrichloromethane as solvent first produced hLs[trifiuoromethyl] tellurium chloride fluoride. When the reaction mixture was concentrated, the F-NMR signal of the chloride fluoride disappeared and was replaced by signals for bis[trifluoromethyl] tellurium difluoride and bis[trifluoromethyl] tellurium dichloride. The diorgano tellurium dihalides reported in the literature as mixed dihalides might be mixtures of symmetrical dihalides. All mixed halide species were identified by Te- and F-NMR spectroscopy in dimethylformamide solutions prepared from equimolar amounts of two different tellurium dihalides.  

From Diorgano Tellurium Compounds and Interhalogen Compounds 

Diorgano tellurium compounds and iodine chloride or iodine bromide combine in chloroform or diethyl ether solution to produce diaryl tellurium iodide halides  

Irgolic Organo Tellurium Compounds with 2 Te—C Bonds or 1 Te = C Bond 

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Reaction of Diorgano Tellurium Dihalides with Sodium Sulfide General Procedure A 15-fold molar excess of sodium sulfide nonahydrate is mixed with the diorgano tellurium di halide and the mixture is heated at 90-95° on a boiling water bath. When the mixture has become liquid, it is stirred for an additional 10 min. and then cooled. Water is added to dissolve the sulfide and the mixture is filtered to collect the solid diorgano tellurium product. Liquid diorgano tellurium products are extracted into petroleum ether. Products are purified by recrystallization or distillation. 

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