Aryltellurinic acids

Aryltellurium trihalides are sensitive to water and can be converted into products at different stages of hydrolysis. Oxohalides, aryltellurinic acids and aryltellurium anhydrides have been known for a long time, the oxohalides being the products of partial hydrolysis. 

Aryltellurinic acids were described in the early period of tellurium chemistry as the products of the alkaline hydrolysis of the trichlorides. However, the structure of these compounds was later argued about, and the corresponding anhydrides are today accepted as the unequivocal products.The anhydrides are stable, colourless, solids with high melting points and have recently attained a relevant role as synthetic reagents. 

Anchored aryltellurinic acid has a catalytic activity on the epoxidation of olefins.The reagent is prepared by reaction of tellurium tetrachloride with divinylbenzene-styrene copolymer, followed by hydrolysis of the formed trichloride. 

Diaryltellurium oxides 8 and aryltellurinic acid anhydrides 9 are white solids and find use as mild oxidizing agents in organic synthesis. These classes of organic tellurium compounds are quite stable and can be handled with no need for special care. 

Aryltellurinic acid anhydrides 9 are prepared by alkaline hydrolysis of aryltellurium trihalides 5, followed by acidification.84-86 The anhydrides 9 precipitate as white solids in high yields (Scheme 15). 

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