Organometallic species tellurium

The environmental impact of tin is appreciable, as it is one of the three most enriched metals—only lead and tellurium precede—in the atmospheric particular matter, as compared with the abundance of the element in the earth crust (2.2 ppm). Tin releases to the environment can be methylated by aquatic organisms, yielding organometallic species of toxicity comparable to that of methylated mercury5. 

The introduction of tellurium into an organic substrate promotes functional groups transformations or presents structural features that can be used for synthetic purposes, if suitable methods to remove tellurium from the resulting structures are available. To date, four main strategies have been explored for this end, namely, the telluroxide elimination, the tellurium/metal exchange, the coupling of tellurides with organometallic species and with alkynes, and the reductive removal via free radicals. 

A considerable number of organometallic species have been detected in the natural environment in recent years. A number of these are nonmethyl compounds which have entered the environment after manufacture and use (e.g. butyltin and phenyltin compounds in antifouling paints for boats). Only a few methyl compounds are now manufactured and used (e.g. methyltin compounds for oxide film precursors on glass and methylarsenic for compounds used as desiccants or defoliants). It is now well established that certain organometallic compounds are formed in the environment, unequivocally so for those of mercury, arsenic, selenium, tellurium and tin, and deduced on the basis of analytical evidence for lead, germanium, antimony and thallium . 

Since the publication of the chapter Tellurium in the second edition of this encyclopedia,12 a number of methods to transform organotellurium compounds into tellurium-free reactive organometallics and the use of such species in stereoselective carbon-carbon bond formation have been developed. Coupling reactions of organotellurium... 

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