From potassium tellurocyanate and arenediazonium fluoroborates

Another method that uses arenediazonium fluoroborates to prepare diaryl tellurides is the reaction with potassium tellurocyanate. Aryl teUurocyanides are postulated as intermediates. 

Ar = alkyl, methoxy, nitre, cyano, halophenyl derivatives, 2-biphenyl 

The small amounts of diaryl ditellurides formed frequently as by-products can be converted into tellurides by treatment with copper powder in refluxing dioxane. For Ar=2H02CC6H4, the crude product is extracted with aqueous Na2C03 and precipitated with acid (yield 8%). 

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