Telluride dihalides diaryls

Diaryltellurium dihalides (general procedure) The diaryl telluride dissolved in a small amount of benzene or CHCI3 is treated dropwise, while cooling (ice bath) and stirring, with a solution of an equimolar amount of SO2CI2, Br2 or I2 in the same solvent (in the case of SO2CI2, evolution of SO2 is observed). By addition of a large excess of petroleum ether at 30-60°C (50 mL for 1 mmol) the dihalide precipitates as a crystalline solid (the dichlorides are colourless, the dibromides yellow and the diiodides red). The yields are quantitative. 

The diaryl tellurides combine with halogens to form dihalides, R2TeX2, and with mercuric halides mercurihalides are produced, R2Te.HgX2. 

The reaction of aryltellurium trichlorides 116 with activated aromatics 117 gives the corresponding diaryltellurium dihalides 118, which by reduction give the diaryl tellurides 119.5 11 12 55... 

Reduction of Organoselenium and -tellurium Halides and Oxides. TUD reduces aryltellurium trihalides to diaryl ditel-lurides (eq 2) and diorganyltellurium dihalides and telluroxides to diorganyl tellurides (eq 3) in high yield. The corresponding selenium compounds are reduced similarly. Some examples are given in Table 2. The reduction is performed by premixing the substrate and 2 N NaOH at room temperature for 15 min prior to the addition of TUD in petroleum ether. 

Similarities are noted between the mass spectra of aliphatic and aromatic selenides with analogous sulphides and phosphines. " Selenoxides show the expected fragments derived from the selenate rearrangement product " " Extensions of these studies cover selenium dihalides (no moleculm ion is seen " ), seleninic acids and esters, " and selenones. Mass spectra of diaryl tellurides are very much like those of S and Se analogues. ... 

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