Organotellurium chemistry
Organotellurium chemistry describes the synthesis and properties of chemical compounds containing a carbon-tellurium chemical bond. Organotellurium chemistry is a lightly studied area, in part because of the few applications. Functional groups. The Te analogues of common organosulfur and organoselenium functional groups are known. Tellurols are however unstable with respect to oxidation to the ditellurides. Commonly encountered organotellurium compounds are diorganomono- and ditellurides, RTe and (RTe), respectively. Two other families of organoTe(IV) compounds are well developed: RTeCl and the telluroxides (RTeO). Synthesis and reactions. Reduced organoTe compounds. Reduced organoTe compounds are commonly obtained from NaHTe and lithium telluride : A direct route to organolithium compounds starts from reactions of organolithium or Grignard reagents and Te: Butyl lithium gives the telluride similarly: Organotelluride anions can be oxidized or alkylated: Diorganoditellurides are valued intermediates, especially the aryl derivatives such as diphenyl ditelluride: Derivatives of TeCl. One departure from sulfur and selenium chemistry is the availability of the tetrachloride, TeCl. It reacts with arenes to give aryltellurium trichlorides: For electron-rich arenes, the disubstitution occurs Tellurium tetrachloride adds across alkenes and alkynes to the chloro tellurium trichlorides: Organotellurium trichlorides adopt dimeric structures, reflecting the Lewis acidity of the Te(IV) center. The dimers  are cleaved by halides and other Lewis bases: The anions RTeCl (and the related adducts RTeClL) adopt square pyramidal structures with the electronegative groups in the plane. Organotellurium(IV) chlorides are susceptible to substitution reactions where by chloride is repaced by other halides and pseudohalides. The TeClx group can also be removed with Raney nickel. OrganoTe(IV) compounds participate in Stille reactions: Telluroxides. Telluroxides are generally related to sulfoxides and selenoxides in terms of their structures. Unlike their lighter analogues however, they polymerize (reversibly) when crystallized. Analogous to selenoxide oxidation, allylic telluroxides undergo [2,3]-sigmatropic rearrangements forming allylic alcohols after hydrolysis. Also analogous  to the selenoxide elimination, certain telluroxides give alkenes upon heating. Applications. Dimethyl telluride is used to in metalorganic vapour phase epitaxy where it serves as a volatile source of Te. It is the only organotellurium compound that has been quantified in environmental samples.