2,2′-Bithiophene is the
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...
. It is a colorless solid, although commercial samples are often greenish.
It is the most common of the three
isomers with formula (C
4H
3S)
2. The other two isomers have the connectivity 2,3′- and 3,3′-. The compound is typically prepared by
cross-coupling starting from 2-halo
thiophene
Thiophene is a heterocyclic compound with the formula C4H4S. Consisting of a planar five-membered ring, it is aromatic as indicated by its extensive substitution reactions. It is a colorless liquid with a benzene-like odor. In most of its react ...
s.
X-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
shows that the two rings are coplanar,
[ unlike the situation for ]biphenyl
Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one ...
.
Occurrence
A number of bi- as well as terthiophene
Terthiophene is the organic compound with the formula 4H3Ssub>2C4H2S. It is an oligomer of the heterocycle thiophene, a shorter oligomer is dithienyl, and the parent polymer is polythiophene. In the most common isomer of terthiophene, two thien ...
s exist naturally, invariably with substituents at the positions flanking sulfur. In terms of the biosynthesis, bithiophenes are proposed to be derived from polyacetylenic precursors, which in turn are the products of dehydrogenation
In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At ...
of oleic acid
Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated omeg ...
. According to some hypotheses, these polyalkynes form labile 1,2-dithiins via a reaction with H2S2 or its equivalent.[.]
References
{{DEFAULTSORT:Bithiophene, 2,2'-
Thiophenes