From Tellurium Chlorides

Aryl tellurium chlorides, prepared by halogenolysis of diaryl ditellurium compounds, combined with yv.Af-dichlorobenzenesulfonamide in carbon tetrachloride to produce an equimolar mixture of aryl tellurium chloride benzenesulfonimide and aryl tellurium trichloride.  

4-Methoxy phenyl Tellurium Chloride Benzenesulfonimide b To 3 0 m/ of carbon tetrachloride are added 1.17 g (2.5 mmol) of bis[4-methoxyphenyl] ditellurium, the solution is cooled to - 10 with stirring, and 0.19 g (2.7 mmol) of chlorine dissolved in 5 ml of carbon tetrachloride are added. The mixture is stirred for 20 min, warmed to 20°, and a solution of 0.29 g (1.3 mmol) of A,A-diehlorobenzenesulfonamide in 40 ml of carbon tetrachloride is added. The mixture is allowed to stand overnight and is then filtered. The solid is washed with several 5 w/portions of diethyl ether/dioxane (5/1, v/v) and the remaining solid is recrystallized from dioxane or toluene yield 0.41 g (78%) m.p. 202°. 

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Chloro(trifluoromethyl)methyleneamino tellurium pentafluoride was similarly prepared2 from tellurium chloride pentafluoride and trifluoromethyl cyanide. The product could be purified only by preparative gas chromatography on a 15% Halocarbon K-352 column. The vapor pressure of the pure compound was 50 torr at 25°. 

Triethyl tellurium chloride,2 (CgHg TeCl, is isolated when an ether solution of tellurium tetrachloride is added dropwise to a similar solution of zinc diethyl. It crystallises from alcohol as colourless plates, M.pt. 174° C., readily soluble in alcohol, sparingly soluble in ether. It is deliquescent in air, and with moist silver oxide gives a hydroxide. 

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... 

Bis[morpholino] tellurium dichloride was also obtained from bis[tetrafluoropropoxy] tellurium dichloride or tris[tetrafluoropropoxy] tellurium chloride and iV-trimethylsilyl-morpholine3. 

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. 

Phenylazo)phenyl tellurium acetate was prepared from the aryl tellurium chloride and sodium acetate. The tellurium atom is in a trigonal bipyramidal environment with the oxygen and one nitrogen atom in the two axial positions1. 

Phenylazo)phenyl Tellurium Acetate1 A solution of 0.082 g (1 mmol) of sodium acetate in 20 ml dry methanol is added under an atmosphere of nitrogen to a stirred solution of 2-(phenylazo)phenyl tellurium chloride (0.344 g, 1 mmol) in 25 ml dichloromcthanc at 20°. The mixture is stirred for 20 min and the solvents removed on a rotary evaporator. 100 ml dichloromethane are added to the residue. The mixture is stirred vigorously and then filtered to remove insoluble sodium chloride The solvent is removed from the filtrate on a rotary evaporator. 5 ml methanol are added to the residue, the mixture is stirred well, and then filtered to collect the product. The crude material is dissolved in petroleum ether (60-80°). Slow evaporation of the solvent caused golden-orange crystals to form yield 75% ,fn.p. 121-122° (dec.). 

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. 

Aryl tellurium chlorides, generated from diaryl ditelluriums and chlorine and used in situ, reacted with A.iV-dichloroarenesulfonamides. Aryl tellurium trichlorides and aryl (chloro)tellurium arenesulfonimides were obtained9. 

Diisopropyl Ditellurium [Sodium Hydride Method]2 A 500 ml flask fitted with a magentic stirrer and a reflux condenser is purged with nitrogen and charged with 15.0g (0.11 mol) of tellurium and 100 m/ of dimethylformamide (freshly distilled from calcium chloride). 5.64 g of a 50% suspension of sodium hydride (0.11 mol) in mineral oil are added, the mixture is slowly heated over 1 h to 70° with stirring on a water bath, maintained at this temperature for 3 h, and then allowed to cool to 20°. 14.50 g (0.11 mol) of isopropyl bromide are added dropwise over 30 min, the mixture is stirred for 30 min, poured into 200 ml of water, and extracted with three 25 ml portions of chloroform. The combined extracts are washed with three 25 ml portions of distilled water, dried with anhydrous calcium chloride, and the solvent removed under aspirator vacuum. The residue is purified by chromatography on silica gel with hexane as the mobile phase yield 13.5 g (72%) b.p. 92°/2 torr. 

Bis[2-benzoylphcnyl] Ditellurium [Potassium Hydroxide Method]3 To 200 ml of ethanolic potassium hydroxide are added 16.5 g (48 mmol) of 2-benzoylphenyl tellurium chloride and the mixture is heated until the reddish color disappears and potassium chloride precipitates. The mixture is poured into cold water and the ditellurium compound is extracted with chloroform. The extract is dried, evaporated to dryness, and the residue is recrystallized from benzene yield 12.3 g (83%) m.p. 139°. 

Organo tellurium trifluorides, trichlorides, tribromides, and triiodides are known. Aryl tellurium trihalides are generally more stable than alkyl tellurium trihalides. The sensitivity toward atmospheric agents decreases from the trichlorides to the triiodides. Very few organo tellurium trifluorides have been prepared and little is known about their reactivity. The general reactivity of aryl tellurium trihalides decreases from the chlorides to the iodides. 2-Chloroalkyl tellurium trichlorides, products of the addition of tellurium... 

The compound decomposed on storage with deposition of tellurium1. Tellurium tetrachloride need not be used in substance it can be generated in the reaction mixture from tellurium dioxide and acetyl chloride or chlorotrimethylsilanc. With acetyl bromid tellurium tetrabromide can be formed. When cyclohexene was present in the reaction mixture, 2-halocyclohexyl tellurium trihalides were isolated in approximately 70% yields. Acetic acid, chloroform, or dichloromethane may be used as solvents2. 

The reactivity of the tellurium trihalides decreases from the chlorides to the iodides. The aryl tellurium triiodides do not form diaryl tellurium diiodides and do not react with acetone6. 

Benzoylphenyl Tellurium Cyanide2 An intimate mixture of 1.65 g (5 mmol) of 2-benzoylphenyl tellurium chloride and 1.5 g (10 mmol) of anhydrous silver cyanide is heated in an oil bath until the material has melted. The mixture is then allowed to cool to 20° and is extracted with chloroform. The chloroform extract is evaporated to dryness and the residue is recrystallized from hexane/benzene yield 1.3 g(80%) m.p. 135°. Similarly prepared was ... 

The formation of ethenylphenyl tellurium in 20% yield from tellurium and acetylene at 100° in a system containing potassium hydroxide, tin(II) chloride, water, and hexamethylphos-phoric triamide in the presence of iodobenzene can be explained by the arylation of potassium ethenetellurolate, a likely intermediate in this reaction3. 

Sodium telluride, prepared from tellurium and sodium borohydride in aqueous medium, reacted with benzoyl chlorides using a phase transfer technique, to produce rather unstable 7e-benzyl tellurobenzoates (benzyl benzoyl telluriums)1 in low yields and not the expected dibenzoyl telluriums. Sodium telluride must reduce benzoyl groups to benzyl groups during these reactions. 

Only a few representatives of tellurocarboxylic acid anhydrides have been prepared from tellurium, sodium telluride, or bis[trimethylsilyl] tellurium and alkanoyl or arenoyl chlorides. Diacyl telluriums are stable at 20°, however, they are very sensitive to air and moisture. 

Sodium hydrogen telluride, prepared from tellurium and sodium borohydride in ethanol/acetic acid, reacted with organyloxy-(/m.-butyl )-methylenedimethy1iminium chloride, obtained from A,A-2,2-tetramethylpropionamide and phosgene, to form organo... 

Arenediazonium tetrafluoroborates were unreactive towards tellurium3 under conditions that had produced diaryl tellurium dichlorides from arenediazonium chlorides. However, addition of lithium chloride to a mixture of tellurium and 4-nitrobenzenediazonium tetrafluoroborate led to the formation of bis[4-nitrophenyl] tellurium dichloride in 33% yield2. 

Treatment of diaryl tellurium dichlorides, obtainable from tellurium tetrachloride and aromatic compounds, with carbon monoxide in the presence of palladium(II) chloride/lithium chloride gives arenecarboxylic acids. Biaryls are formed as by-products1,2. Similar products were obtained when the diaryl tellurium dichlorides were reacted with nickel tetracarbonyl3. 

The reaction of bis[trifluoromethyl] tellurium with chlorine fluoride at — 78° with fluorotrichloromethane as solvent first produced his[trifluoromethyl] tellurium chloride fluoride. When the reaction mixture was concentrated, the l9F-NMR signal of the chloride fluoride disappeared and was replaced by signals for bis[trifluoromethyl] tellurium difluoride and bis[trifluoromethyl] tellurium dichloride2. The diorgano tellurium dihalides reported in the literature as mixed dihalides might be mixtures of symmetrical dihalides. All mixed halide species were identified by 125Te- and 19F-NMR spectroscopy in dimethylformamide solutions prepared from equimolar amounts of two different tellurium dihalides3. 

Diethyl Tellurium Chloride Hydroxide4 Diethyl tellurium dichloride is added to an excess of aqueous ammonia and the mixture is carefully heated until the tellurium compound has dissolved. The solution is then concentrated until the product crystallizes. The product is recrystallized from ethanol. 

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°... 

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