Tellurium Tribromide

Like chlorinolysis, the brominolysis and iodinolysis of diorganyl ditellurides offer a facile route to tellurium tribromides and triiodides. ... 

Similarly trimethvl tellurium bromide and methyl tellurium tribromide combine together in molecular proportions to give Vernon s /3-di-bromide. To counter the objection that j8-dihalides might be formed by a rearrangement according to the equation... 

Compound (CH3)3TeBr.CH3TeBr3 (Vernon s j8-dibromide).— Trimethyl tellurium bromide and methyl tellurium tribromide when dissolved in equimolecular proportions in a little acetone combine to yield this molecular compound. The yellow solution on dilution with chloroform deposits lustrous yellow spangles, decomposing at 142° C. 

Methyl tellurium tribromide, CH3TeBr3, forms yellow needles, becoming discoloured above about 140° C., rapidly near 150° C., the dark mass melting to a black effervescing tar at 156° C. The yellow solution in acetone is not precipitated by chloroform. 

The purified bis[9-e>-carboranyl] ditellurium was reacted in dichloromethane with the stoichiometrically required amount of thionyl chloride to produce the 9-o-carboranyl tellurium trichloride and with bromine to give the corresponding tellurium tribromide. The tellurium trichloride was reduced with an excess of hydrazine hydrate in ethanol to bis[9-o-... 

Phenylseleno phenyl tellurium reacted with bromine to form phenyl tellurium tribromide and phenyl selenium tribromide1. 

Nitrophenyl Tellurium Bromide1 0.42 g (6 mmol) of solid sodium hydrogen sulfite are added over a period of 20 min to a stirred suspension of 1.0 g (3 mmol) of 2-nitrophcnyl tellurium tribromide in water at 0°. The resultant deep-red slurry is stirred for 20 min at 0°, filtered, the red paste is dissolved in dichloromethane, filtered again, and the dichloromethane solution is diluted with hexane. The product crystallizes as a deep-red solid yield 0.59 g (80%) m.p. 76°. 

Aryl tellurium tribromides were reduced with hydrazine hydrate in ethanol1 2 or with sodium borohydride in ethanol1. 

Bis[2-(quinolin-2 -yl)phenyl] Tritellurium4 To a suspension of 2.28 g (4.0 mmol) 2-(quinolin-2 -yl)phenyl tellurium tribromide in 25 ml ethanol are added 0.26 g (4 mmol) tellurium powder. The mixture is stirred under argon. A solution of 1.1 g (30 mmol) sodium borohydride in 20 ml ethanol is slowly added until all the... 

The halogenolysis of dialkyl ditellurium compounds is a convenient method for the preparation of alkyl tellurium trihalides because dialkyl ditellurium compounds are easily accessible through alkylation of disodium ditelluride (p. 258). Diaryl ditellurium compounds generally obtained via reduction of organo tellurium trichlorides (p. 274), serve as starting materials for the syntheses of aryl tellurium tribromides and triiodides (Vol. IX, p. 1156) that are not obtainable from the hydrocarbons and tellurium telrabromide or tetraiodide. 

The following aryl tellurium tribromides were obtained similarly ... 

Similarly obtained were the corresponding tellurium tribromide (m.p. 293-295° from CHCl3/hexane yield 84%) and tellurium triiodide (m.p. 201 from CHC13 yield 97%) . 

The reactions of 2-nitrophenyl benzyl tellurium4, 2-phenylazophenyl 4-ethoxyphenyl tellurium5, and l-oxo-l,3-dihydro-2-benzotellurophene6 with bromine that produce organo tellurium tribromides, very likely proceed via diorgano tellurium dibromides as intermediates. 

Chloro-4-hydroxyphenyl Tellurium Tribromide (Triiodide)2 To a saturated solution of 1.0 g (2.8 mmol) of 3-chloro-4-hydroxyphenyl tellurium trichloride in 10 ml of methanol is added a solution of 1.2 g (10 mmol) of potassium bromide [or 1.7 g (10 mmol) of potassium iodide] in 30 ml of methanol. The solution darkens immediately and deposits potassium chloride 50 m/ of diethyl ether are added to precipitate additional potassium chloride and unreacted potassium bromide (or iodide). The mixture is filtered and the filtrate is concentrated under vacuum until the product crystallizes. 

The reaction between tellurium tetrabromide and cycloheptene with ethanol as the solvent yielded 2-ethoxycycloheptyl tellurium tribromide2. The 2-bromocycloheptyl tellurium tribromide, a likely intermediate, could have reacted with ethanol. 

Equimolar amounts of aryl tellurium tribromides and ammonium dialkyl dithiophos-phates produced aryl tellurium dibromide dialkyldithiophosphates3. 

Phenyl tellurium tribromide was quantitatively transformed to benzenetellurinic anhydride upon treatment with 10% aqueous sodium hydroxide in tetrahydrofuran at 20° for 12 hours3. 

Methoxyphenyl Tellurium Cyanide4 2.45 g (29.2 mmol) of sodium hydrogen carbonate is dissolved in a mixture of 50 ml of water and 3 ml of methanol and 5.0 g (14.2 mmol) of 4-melhoxyphenyl tellurium tribromide is added. The mixture is stirred for 0.5 h, 3.70 g (58.4 mmol) of potassium chloride followed by ll.Og (58.4 mmol) of sodium disulfite are added, the resultant mixture is stirred for 8 min, and 3.70 g (58.4 mmol) of potassium cyanide are added. A white precipitate forms. The reaction mixture is diluted with water, extracted with dichloromethane, the organic phase is dried with anhydrous sodium sulfate, and filtered. The filtrate is diluted with hexane and the resultant solution is concentrated by distilling some of the solvent. The precipitate is filtered yield 3.60 g (93%) m.p. 77°. 

Phenoxyphenyl tellurium tribromide did not react with 1,2-dihydroxybenzene1. The reactions of phenyl tellurium trichloride2 and 4-ethoxyphenyl tellurium trichloride3 with methoxybenzene were carried out at a temperature of 160°. 

Phenoxyphenyl tellurium trichloride and the aryl tellurium tribromides and triiodides did not react at 20°. Upon heating haloacetones were formed1. 

The phenyl tellurium tribromide can be prepared in situ from diphenyl ditellurium and bromine. Olefins thus far investigated include isobutene, (E)- and (Z) -butene, 1 -hexene, 2-methyl-l-pentene, 1-octene, (E)- and (Z)-4-octene, 1-decene, phenylethene, 1-phenyl-I-methylethene, cyclopentene, cyclohexene, cycloheptene, and cyclooctene. Most of the reactions were carried out with phenyl tellurium tribromide in methanol. 

Methyl phenyl and 4-methoxyphenyl tellurium trichloride reacted similarly with cyclohexene in methanol solution. The butoxy group was not introduced into the molecule when the reactions were performed in o rf.-butanol. In aqueous /erf.-butanol or aqueous THF, phenyl tellurium tribromide and cyclohexene reacted to give a 50% yield of 2-hydroxycyclohexyl phenyl tellurium dibromide. ... 

Bis[2-(2 -pyridyl)phenyl] tellurium dibromide prepared from 2-(2 -pyridyl)phenyl tellurium tribromide and 2-(2 -pyridyl)phenyl mercury chloride was isolated as the 1 1 adduct (m.p. 235-238°) with mercury bromide chloride1. 

The addition of phenyl tellurium tribromide to internal alkenes in methanol as solvent gives vic-methoxyalkyl phenyl tellurium dibromides. Treatment of these dibromides with 0.5 M aqueous sodium hydroxide solution produces a-methoxyalkenes via an intermediate alkyl phenyl tellurium oxide2,3. The same reaction sequence but starting with terminal olefins3 or cyclohexene2 leads to 2-methoxy-l-alkyl phenyl tellurium oxides, which decompose only at 250° in a vacuum. 

Addition of phenyl tellurium tribromide to terminal olefins in methanol as the reaction medium, yields 2-methoxyalkyl phenyl tellurium dibromide. Hydrolysis of the dibromidcs with sodium hydroxide in aqueous THF produces 2-methoxyalkyl phenyl tellurium oxides, which, upon heating at 240°, form 2-methoxyalkenes1,2. 

Decene and phenyl tellurium tribromide reacted in methanol to produce 2-methoxydecyl phenyl tellurium dibromide, which was hydrolyzed to the tellurium oxide. Treatment of the tellurium oxide with 3-chloroperoxybenzoic acid in methanol give 1,2-dimethoxydecane in 84% yield5,6. 

When 2-phenyl-2-methoxy-2-R-ethyl or -propyl phenyl telluroxides (obtained from phenylethylenes and phenyl tellurium tribromide in methanol followed by hydrolysis of the tellurium dibromide) were treated with 3-chloroperoxybenzoic acid in methanol at 20°, the phenyl group migrated to the methylene group from which the tellurium moiety had been... 

Biphenylyl tellurium tribromide is reported to yield dibenzotellurophene dibromide when heated at its melting point of 181 4. 

Methylphenylimino)methyl]phenyl Tellurium Bromide A solution of 1.60 g (10 mmol) bromine in 40 ml chloroform are added dropwise to the vigorously stirred solution of 3.80 g (10 mmol) butyl 2-(4 -methyIphenylimino)methylphenyl tellurium in 40 ml chloroform. The mixture is heated to the boiling point and then cooled. The mixture is filtered to remove a small amount of the aryl tellurium tribromide. The filtrate is concentrated to 20 ml and then mixed with 20 ml dry diethyl ether. The yellow crystals arc collected by filtration, washed with diethyl ether, and dried yield 92% m.p. 170°. 

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