Tellurium Chloride Iodide

Diaryl tellurium chloride iodides precipitate silver chloride when treated with one equivalent of a silver pseudohalide and form diaryl tellurium iodide pseudohalides1,2. With two equivalents of silver pseudohalides, diaryl tellurium dipseudohalides are produced1-2. 

Bis[4-methoxyphenyl] tellurium chloride iodide reacted with tetraethylammonium bromide to produce bis[ietraethylammonium] bis[4-methoxyphenyl] dibromodichloro-tellurate(IV). ... 

Diphenyl tellurium iodide cyanate slowly decomposes even at low temperature1. Surprisingly, when diaryl tellurium chloride iodides were stirred with equimolar amounts of silver pseudohalides in chloroform, silver chloride was surprisingly precipitated instead of the more insoluble silver iodide. The diaryl tellurium iodide pseudohalides were isolated in almost quantitative yields12. 

Diphenyl Tellurium Cyanate Iodide1 0.89 g (2 mmol) of diphenyl tellurium chloride iodide and 0.30 g (2 mmol) of silver cyanate in 30 ml of chloroform are stirred at 20°. The precipitated silver chloride is filtered and the filtrate is concentrated to give yellow needles of the product yield 95% m.p. 80°. 

From Diaryl Tellurium Chloride Iodides and Silver Cyanide... 

Surprisingly, when diphenyl tellurium chloride iodide is stirred with an equimolar amount of silver cyanide in chloroform, silver chloride is precipitated instead of the more insoluble silver iodide and diphenyl tellurium iodide cyanide (m.p. 142°) was isolated in almost quantitative yield1."... 

Diphenyl Tellurium Chloride Iodide 1.12 g (4 mmol) of diphenyl tellurium is dissolved in 50 ml of diethyl ether, the solution is cooled to — 5°, and 0.65 g (4 mmol) of iodine monochloride dissolved in 5 m/ of diethyl ether are added dropwise to the stirred solution. Stirring is continued for 1 h, and the orange-red precipitate is filtered off and dried under vacuum yield 1.6 g (90%) m.p. 204 . 

Di-o-tolyl methyl tellurium chloride,2 (C7H7)2(CH3)TeCl, is obtained by boiling the corresponding iodide with silver chloride and water. It separates from water as four-sided plates containing two molecules of water of crystallisation, melting at 93° C. and again at 148° C. from chloroform it crystallises with half a molecule of chloroform, and melts at 155° to 156° C. The basic zinc chloride double salt melts with decomposition at 186° to 187° C. 

Tri-p-tolyl tellurium iodide1 melts with decomposition at 232° to 233° C., dissolves readily in methyl alcohol or chloroform, less readily in benzene or ether, and is insoluble in water. Tri-p-tolyl tellurium bromide occurs when the iodide or chloride is boiled with silver bromide. It melts at 265° to 266° C. with decomposition, and dissolves in alcohols or chloroform, but is insoluble in benzene or ether. Tri-p-tolyl tellurium chloride is prepared from the bromide in the usual way. It melts at 260° to 261° C. and gives precipitates with the chlorides of mercury, tin and gold, picric acid and platinic chloride. The hydroxide is a resin, melting at about 110° C., and yielding a pier ate, consisting of long prisms, M.pt. 194° to 195° C.a... 

Solutions of sodium tellurite in water1,2 or prepared from tellurium dioxide and aqueous sodium hydroxide3 were acidified with sulfuric acid and treated with freshly prepared solutions of bis[2-hydroxyethyl]dithiocarbamic acid in aqueous methanol. Addition of aqueous solutions of potassium chloride, iodide, or thiocyanate led to the deposition of crystalline tris[bis(2-hydroxyethyl)dithiocarbamate] halides. 

Only a few unsubstituted, non-stabilized alkyl tellurium halides were characterized or isolated. /-Butyl tellurium chloride may have been detected by l2STe-NMR spectroscopy as a minor product of the controlled chlorination of di-/-butyl ditellurium6. 2-Chlorocarbon-ylbenzyl tellurium halides were obtained as rather unstable solids by halogenolysis of tellurophthalide7 (p. 246). Tris[trimethylsilyl methyl tellurium chloride, bromide and iodide were isolated as black-blue crystals that were stable in solution and as solids8. The stability of these compounds is attributable to the steric protection of the Te —X group by the trimethylsilyl substituents. 

The possibility of preparing aryl tellurium halides from equimolar amounts of diaryl ditellurium compounds and aryl tellurium trihalides has hardly been explored. Only phenyl tellurium iodide and 2-biphenylyl tellurium bromide could be obtained by this route. The other aryl tellurium halides (including 3,4-dimethoxyphenyl tellurium chloride) decomposed under the reaction conditions to give diaryl tellurium dihalides and tellurium5. 

With thionyl chloride the corresponding tellurium chloride (m.p. 178°, from chloroform, 52% yield) and with iodine the tellurium iodide (m.p. 168°, from chloroform-hexane 1 1, 90% yield) were obtained4. 

Because diaryl tellurium diiodides are not hydrolyzed by boiling water, the diaryl tellurium hydroxide iodides were prepared by treating the hydroxide chlorides or bromides with potassium iodide1. 

Diphenyl Tellurium Hydroxide Iodide1 Diphenyl tellurium chloride (or bromide) hydroxide is dissolved in water and a slight excess of potassium iodide dissolved in water is added. The yellow precipitate is filtered off and recrystallizcd from methanol. For dissolution of the product in methanol, the mixture is heated cautiously on a water bath to prevent the hydroxide iodide from disproportionating to the diiodide and the dihydroxide (or oxide). The pure product has m.p. 215°... 

Fig. 2. Comparison of the molecular structures of the tellurium(IV) fluoride, chloride, and iodide types in the solid state. The selenium(IV) chlorides and bromides as well as tellurium(IV) bromide and one of the five forms of tellurium(lV) iodide are isostructural to the cubane-like Te4Cli6 molecules (244).

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