Terthiophene
Encyclopedia
Terthiophene is the organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 with the formula [C4H3S]2C4H2S. It is an oligomer
Oligomer
In chemistry, an oligomer is a molecule that consists of a few monomer units , in contrast to a polymer that, at least in principle, consists of an unlimited number of monomers. Dimers, trimers, and tetramers are oligomers. Many oils are oligomeric, such as liquid paraffin...

 of the heterocycle thiophene
Thiophene
Thiophene is a heterocyclic compound with the formula C4H4S. Consisting of a flat five-membered ring, it is aromatic as indicated by its extensive substitution reactions. Related to thiophene are benzothiophene and dibenzothiophene, containing the thiophene ring fused with one and two benzene...

, a shorter oligomer is dithienyl, and the parent polymer is polythiophene
Polythiophene
Polythiophenes result from the polymerization of thiophenes, a sulfur heterocycle, that can become conducting when electrons are added or removed from the conjugated π-orbitals via doping....

. In the most common isomer
Isomer
In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

 of terthiophene, two thienyl groups are connected via their 2 positions to a central thiophene, also at the carbon atoms flanking the sulfur.

Preparation of terthiophene

Terthiophene is prepared by the nickel- or palladium-catalysed coupling reaction
Coupling reaction
A coupling reaction in organic chemistry is a catch-all term for a variety of reactions where two hydrocarbon fragments are coupled with the aid of a metal catalyst...

 of 2,5-dibromothiophene with the Grignard reagent derived from 2-bromothiophene.

Properties and applications

This isomer is a pigment in African marigold
Tagetes
Tagetes is a genus of 56 species of annual and perennial mostly herbaceous plants in the sunflower family . The genus is native to North and South America, but some species have become naturalized around the world. One species, T...

s (Tagetes
Tagetes
Tagetes is a genus of 56 species of annual and perennial mostly herbaceous plants in the sunflower family . The genus is native to North and South America, but some species have become naturalized around the world. One species, T...

 spp.) and exhibits some biological activity because it sensitizes the formation of singlet oxygen
Singlet oxygen
Singlet oxygen is the common name used for the diamagnetic form of molecular oxygen , which is less stable than the normal triplet oxygen. Because of its unusual properties, singlet oxygen can persist for over an hour at room temperature, depending on the environment...

, which is often lethal. A variety of terthiophenes occur naturally, including 5,5-dichloro-α-terthiophene, 5-chloro-α-terthiophene, 5-acetyl α-terthiophene, and 5-carboxyl bithiophene.

Terthiophene has been employed as building block for the organic semi-conductor polythiophene.

See also

  • Biphenyl
    Biphenyl
    Biphenyl is an organic compound that forms colorless crystals. It has a distinctively pleasant smell. Biphenyl is an aromatic hydrocarbon with a molecular formula 2...

  • Triphenyl
  • Terpyridine
    Terpyridine
    Terpyridine is a heterocyclic compound derived from pyridine. This colourless solid is used as a ligand in coordination chemistry.-Synthesis:...

  • Naphthalene
    Naphthalene
    Naphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...

     where the rings are fused.
  • Tricyclobutabenzene
    Tricyclobutabenzene
    Tricyclobutabenzene is an aromatic hydrocarbon consisting of a benzene core with three cyclobutane rings fused onto it. This compound and related compounds are studied in the laboratory because they are often display unusual conformations and because of their unusual reactivity...

    contains two more hydrogen atoms than biphenyl
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