Potassium ditelluride

This method was later revised replacing sodium ditelluride by potassium ditelluride. ... 

Carboxylalkyltellurium trichlorides, obtained by the reaction of tellurium tetrachloride with carboxylic acid anhydrides, are reduced to the corresponding ditellurides with potassium hydrogen sulphite. - ... 

Reaction of phenylacetylene with Te/KOH/SnCf A mixtnre of 6.4 g of tellurium, 42 g of potassium hydroxide, 22.6 g of SnCl2 2H20, 10.2 g of phenylacetylene, 20 mL of toluene, 60 mL of water and 1.2 g of Adogen 464 was heated (80-97°C) with vigorous stirring for 7 h. The organic layer was separated, and the aqneons layer was extracted with benzene. The benzene was removed under vacnnm. The residne was dissolved in a small amount of ether, poured into 200 mL of isopropyl alcohol, and placed in the refrigerator for 3 days. The yellow crystals of distyryl telluride (2.5 g, yield 15%) and the red needle crystals of distyryl ditelluride (0.7 g, yield 6%) were separated. 

The filtrate from the iodide on evaporation in a desiccator yields a colourless crystalline solid (1 3 grams). Extraction with small quantities of hot water gradually removes any remaining iodide, a white powder remaining as residue. This is an anhydride of methyl hydroocytellurium oxide (telluracetic acid), CH3.TeO.OH, which cannot be obtained pure. In aqueous solution it is neutral to litmus, gives no precipitate with silver nitrate, and is reduced by potassium bisulphite to dimethyl ditelluride. It has a persistent odour, and gradually blackens above 230° C. 

The types of compound obtainable by the condensation of tellurium tetrachloride and mixed ethers may be exemplified by the case of phenetole. The primary product obtained in the reaction is p-phenetyl telluritriehloride (I), which on heating with more phenetole gives Ws-p-phenetyl telluridichloride (II). The latter also occurs if an excess of phenetole be used in the initial condensation. Reduction of the trichloride by aqueous potassium metabisulphite at 0° C. produces bis-p-phenetyl ditelluride (III). 

Reduction of the telluritrichloride by aqueous potassium metabisulphite gives p -diphenoxydiphenyl ditelluride,... 

General procedure To a flame-dried, three-necked, 250 mL, round-bottomed flask equipped with argon inlet, addition funnel and gas bubbler was added 100 mL of dry 1,2-dimethoxyethane (DME) with 0.20 g (0.98 mmol) of triflate [R, R =Me] and 0.50 g (1.2 mmol) of diphenyl ditelluride. The reaction mixture was cooled to -50°C and a solution of potassium f-butoxide (0.15 g, 1.3 mmol) in 50 mL of dry DME was added dropwise. After the addition, stirring was continued for 15 min at -50°C, then the reaction was allowed to warm to room temperature. DME was then removed on a rotary evaporator and the residue taken np in hexane and filtered. The resulting coloured solution was chromatographed on activated silica (hexane as eluent). Isolated yield was 0.12 g (26%), as an orange oil. 

Diaryltellurium trichlorides and dichlorides (Section 3.2) can be converted to diorganyltellurides and ditellurides upon treating with reducing agents such as sodium sulfide, potassium hydrogensulfite, " hydrazine, or thiourea S,S-dioxide. A typical example is shown in Eg. (6). ... 

However, instead of the expected [(Me3Si)Si3Te]4Sn, the reaction of SnCLt and potassium hypersilyltelluride yielded bis(hypersilyl)ditelluride by reduction of the stannane (Eq. 4). 

Sodium dithionite in water or aqueous dimethylformamide is an economic, efficient system for the dehalogenation of a-halo-ketones. Other reagents that have been described recently for dehalogenation include iron-graphite (prepared by reduction of ferric chloride with potassium-graphite), sodium 0,0-diethyl phosphorotelluroate, and sodium borohydride in the presence of a catalytic amount of bis(2-thienyl) ditelluride. ... 

Although there are many ways of preparing both selenocyanates and alkali diselenide (or ditelluride) solutions, only those methods which are used for making the polymers are discussed here. Alkanediselenocyanates can easily be prepared by condensing the dihalide with potassium selenocyanate in solvents like acetone [204], Alkali diselenides (or ditellurides) can be prepared in aqueous solution by reacting sodium formaldehyde sulfoxylate with sdenium (or tellurium) [205] ... 

Morgan and Drew [229] reduced bistrichlorotelluro(IV)methane with potassium metabisulfite and got red-brown ditelluride with a m.p. 50-90°C which was proposed by Berry et al. [230] to be a dimer, (CHjTea) - When this reaction was repeated by Dirk et al. [231], they confirmed the formation of a red powder which subsequently turned into a grey solid. The X-ray diCfiaction results showed both red and grey solids to be amorphous contrary to the crystalline red solid reported previously [229,230]. With X-ray evidence, the red or grey powders have been proposed to be poly(methylene ditelluride) ... 

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