Organotellurium chemistry describes the synthesis and properties of organotellurium compounds, chemical compounds containing a carbon-tellurium chemical bond. Organotellurium chemistry is a lightly studied area, in part because of it having few applications. [1] [2]
The tellurium 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, R2Te and (RTe)2, respectively. Two other families of organotellurium(IV) compounds are well developed: R4−xTeClx and the telluroxides (R2TeO).
Reduced organotellurium 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: [3]
Organotelluride anions can be oxidized or alkylated:
Diorganoditellurides are valued intermediates, especially the aryl derivatives such as diphenyl ditelluride:
One departure from sulfur and selenium chemistry is the availability of the tetrachloride, TeCl4. [5] It reacts with arenes to give aryltellurium trichlorides: [6]
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: [7]
The anions RTeCl4− (and the related adducts RTeCl3L) adopt square pyramidal structures with the electronegative groups in the plane.
Organotellurium(IV) chlorides are susceptible to substitution reactions where by chloride is replaced by other halides and pseudohalides. The TeClx group can also be removed with Raney nickel. [6]
Organotellurium(IV) compounds participate in Stille reactions: [8]
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.
Hexamethylpertellurane was prepared by oxidation of tetramethyltellurium with xenon difluoride. [9] The resulting TeF2(CH3)4 is then treated dimethylzinc:
The octahedral compounds TeAr6 have also been prepared. [10]
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. [11]
Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated forms which are both hygroscopic. They feature iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while all forms are mild oxidizing agent. It is used as a water cleaner and as an etchant for metals.
The Friedel–Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877 to attach substituents to an aromatic ring. Friedel–Crafts reactions are of two main types: alkylation reactions and acylation reactions. Both proceed by electrophilic aromatic substitution.
Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as “tickle” or “tickle 4”, as a phonetic representation of the symbols of its molecular formula.
Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms a hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are colourless crystals, but samples are often contaminated with iron(III) chloride, giving them a yellow colour.
Organotin chemistry is the scientific study of the synthesis and properties of organotin compounds or stannanes, which are organometallic compounds containing tin–carbon bonds. The first organotin compound was diethyltin diiodide, discovered by Edward Frankland in 1849. The area grew rapidly in the 1900s, especially after the discovery of the Grignard reagents, which are useful for producing Sn–C bonds. The area remains rich with many applications in industry and continuing activity in the research laboratory.
Rhodium(III) chloride refers to inorganic compounds with the formula RhCl3(H2O)n, where n varies from 0 to 3. These are diamagnetic solids featuring octahedral Rh(III) centres. Depending on the value of n, the material is either a dense brown solid or a soluble reddish salt. The soluble trihydrated (n = 3) salt is widely used to prepare compounds used in homogeneous catalysis, notably for the industrial production of acetic acid and hydroformylation.
Gold(III) chloride, traditionally called auric chloride, is an inorganic compound of gold and chlorine with the molecular formula Au2Cl6. The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. It has two forms, the monohydrate (AuCl3·H2O) and the anhydrous form, which are both hygroscopic and light-sensitive solids. This compound is a dimer of AuCl3. This compound has a few uses, such as an oxidizing agent and for catalyzing various organic reactions.
In inorganic chemistry, chlorosilanes are a group of reactive, chlorine-containing chemical compounds, related to silane and used in many chemical processes. Each such chemical has at least one silicon-chlorine bond. Trichlorosilane is produced on the largest scale. The parent chlorosilane is silicon tetrachloride.
Organoselenium chemistry is the science exploring the properties and reactivity of organoselenium compounds, chemical compounds containing carbon-to-selenium chemical bonds. Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected. Organoselenium compounds are found at trace levels in ambient waters, soils and sediments.
Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound, with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry.
1,2,3,4,5-Pentamethylcyclopentadiene is a cyclic diene with the formula C5(CH3)5H, often written C5Me5H, where Me is CH3. It is a colorless liquid.
Titanium(III) chloride is the inorganic compound with the formula TiCl3. At least four distinct species have this formula; additionally hydrated derivatives are known. TiCl3 is one of the most common halides of titanium and is an important catalyst for the manufacture of polyolefins.
Tellurium tetrachloride is the inorganic compound with the empirical formula TeCl4. The compound is volatile, subliming at 200 °C at 0.1 mmHg. Molten TeCl4 is ionic, dissociating into TeCl3+ and Te2Cl102−.
Gallium trichloride is the chemical compound with the formula GaCl3. Solid gallium trichloride exists as a dimer with the formula Ga2Cl6. It is colourless and soluble in virtually all solvents, even alkanes, which is truly unusual for a metal halide. It is the main precursor to most derivatives of gallium and a reagent in organic synthesis.
Organotitanium chemistry is the science of organotitanium compounds describing their physical properties, synthesis, and reactions. Organotitanium compounds in organometallic chemistry contain carbon-titanium chemical bonds. They are reagents in organic chemistry and are involved in major industrial processes.
Trimethyltin chloride is an organotin compound with the formula (CH3)3SnCl. It is a white solid that is highly toxic and malodorous. It is susceptible to hydrolysis.
Organocerium chemistry is the science of organometallic compounds that contain one or more chemical bond between carbon and cerium. These compounds comprise a subset of the organolanthanides. Most organocerium compounds feature Ce(III) but some Ce(IV) derivatives are known.
Organotantalum chemistry is the chemistry of chemical compounds containing a carbon-to-tantalum chemical bond. A wide variety of compound have been reported, initially with cyclopentadienyl and CO ligands. Oxidation states vary from Ta(V) to Ta(-I).
In organophosphorus chemistry, the Kinnear–Perren reaction (sometimes the Clay-Kinnear-Perren reaction) is used to prepare alkylphosphonyl dichlorides (RP(O)Cl2) and alkylphosphonate esters (RP(O)(OR')2). The reactants are alkyl chloride, phosphorus trichloride, and aluminium trichloride as catalyst. The reaction proceeds via the alkyltrichlorophosphonium salt:
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