Tellurol
Tellurols are organotellurium compounds characterized by the functional group RTeH, where R is an organic substituent. They are the tellurium analogues of alcohols (ROH) and thiols (RSH). Tellurols are generally unstable and prone to oxidation, much more so than thiols or selenols. This instability contributes to the limited study and use of tellurols compared to their sulfur and selenium counterparts.
Properties
The Te-H bond in tellurols is weaker than S-H and Se-H bonds. This weakness contributes to the ease of oxidation and decomposition. Tellurols are typically prepared under anhydrous conditions and used immediately after preparation or stored at low temperatures to prevent decomposition. They are often characterized by their foul odor, a common characteristic of many organochalcogen compounds.
Synthesis
Tellurols can be synthesized through several methods, including:
-
Reduction of Ditellurides: Ditellurides (RTe-TeR) can be reduced using reducing agents such as sodium borohydride or zinc in acid to generate the corresponding tellurols.
-
Reaction of Tellurium with Grignard Reagents: Grignard reagents (RMgX) can react with elemental tellurium to form tellurolates (RTeMgX), which can then be protonated with acid to yield the tellurol.
-
Hydrotelluration of Alkynes: Terminal alkynes can react with hydrogen telluride (H2Te) in the presence of a suitable catalyst to give vinyl tellurols.
Reactions
Tellurols undergo a variety of reactions, including:
-
Oxidation: Tellurols are readily oxidized to ditellurides by air or other oxidizing agents.
-
Deprotonation: Tellurols are more acidic than alcohols or thiols and can be deprotonated by strong bases to form tellurolates (RTe-).
-
Reaction with Electrophiles: Tellurols can react with electrophiles, such as alkyl halides, to form tellurides (R-Te-R').
Applications
Due to their instability and toxicity, tellurols have limited applications. However, they are of interest in research as intermediates in the synthesis of other organotellurium compounds and as ligands in coordination chemistry. They have also been investigated for their potential use in the preparation of tellurium-containing materials for electronic and optical applications.