Tellurols are analogues of

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

s and phenols where tellurium replaces oxygen. Tellurols, selenols, and thiols have similar properties, but tellurols are the least stable. Although they are fundamental representatives of organotellurium compounds, tellurols are lightly studied because of their instability. Tellurol derivatives include telluroesters (RC(O)TeR') and tellurocyanates (RTeCN).

Properties

Alkyltellurols are colorless liquids with strong odors. Samples usually appear yellowish owing to the presence of dialkylditelluride impurities. Near room temperature, methanetellurol degrades with loss of elemental tellurium. It is reported to ignite in air. Aryltellurols are more robust and have been obtained as colorless crystals. Some of the most stable tellurols are the bulky silylated derivatives of

tris(trimethylsilyl)methane Tris(trimethylsilyl)methane is the organosilicon compound with the formula (tms)3CH (where tms = (CH3)3Si). It is a colorless liquid that is highly soluble in hydrocarbon solvents. Reaction of tris(trimethylsilyl)methane with methyl lithium gi ...

and analogues. One series of readily isolable tellurols is , , and .

Acid–base properties

The acidity of tellurols can be inferred by the acidity and dissociation constant of hydrogen telluride, , which has a (first) pK_a of 2.64 corresponding to a dissociation constant of 2.3 × 10^−3.5. has a lower pK_a and higher dissociation constant than and . The pKa is 9.3 for vs 10.8 for . The absence of hydrogen-bonding explains the low boiling temperature of tellurols.

Preparation

The first tellurol to be synthesized, ethanetellurol, was prepared in 1926 via the

Grignard reagent A Grignard reagent or Grignard compound is a chemical compound with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide ...

. The most frequently used method involves reduction of the ditellurides ().

References

{{Functional Groups Organotellurium compounds Hydrides Functional groups