Tetraorgano Telluriums

Only a few tetraorgano tellurium compounds have been synthesized and characterized. Tetraaryl tellurium compounds have a higher thermal stability than tetraalkyl tellurium compounds. Tetraphenyl tellurium has a distorted trigonal bipyramidal geometry.  

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One Te-C bond in tetraorgano tellurium compounds is easily cleaved by water2,3, hydrogen chloride4,5, halogens4,5, dichloromethane, and chloroform2 with formation of triorgano telluronium halides. 

V. Tetraorgano Tellurium, Alkylidene Diorgano Tellurium Compounds, and Hexaorgano Telluriums... 

Triorgano telluronium halides reacted with organic lithium compounds to form tetraorgano tellurium compounds1 5. 

Water, hydrochloric acid, bromine, iodine, and methyl iodide heterolytically cleave one Te — C bond in tetraorgano tellurium compounds with the bonding electron pail remaining with the organic group. The products of these reactions are triorgano tellurium compounds (see p. 692). 

The diorgano tellurium dicarboxylates are white, crystalline materials that are soluble in organic solvents and stable towards atmospheric agents. Diaryl tellurium diacetates can be boiled in water without decomposition. However, bis[trifluoromethyl] tellurium bis trifluoroacetate] was reported to be moisture-sensitive. Aqueous sodium hydroxide converts diaryl tellurium dicarboxylates to diaryl tellurium oxides or dihydroxides . Thermal gravimetric analysis of diaryl tellurium dicarboxylates indicated that these compounds lose carbon dioxide at 240-260° and form the tetraaryl tellurium derivatives. The tetraorgano tellurium compounds decompose slowly to the diaryl tellurium compounds and hydrocarbons. ... 

Triorgano telluronium halides reacted with organo lithium compounds to produce tetraorgano telluriums . 

Tetraorgano tellurium compounds are thermally decomposed to diorgano tellurium compounds and hydrocarbons . Whereas tetramethyl tellurium, tetrabutyl tellurium, and diaryl dialkyl tellurium compounds already form diorgano tellurium compounds by loss of alkyl groups at or below 20° tetraphenyl tellurium tetrakis[pentafluoro-phenyl] telluriumtetrakis[4-methylphenyl] tellurium , and bis[2,2 -biphenyldiyl] tellurium must be heated to at least 100° to effect decomposition. 

V. Compounds with four tellurium-carbon single bonds or two tellurium-carbon single bonds and one tellurium-carbon double bond. Almost all of the tetraorgano tellurium Compounds are aromatic derivatives although tetramethyl tellurium was recently isolated. Aliphatic and aromatic tellurium ylides are known. 

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