Terthiophene Explained

Terthiophene is the organic compound with the formula [C₄H₃S]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 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 of 2,5-dibromothiophene with the Grignard reagent derived from 2-bromothiophene.^[1]

Properties and applications

This isomer is a pigment in African marigolds (Tagetes spp.) and exhibits some biological activity because it sensitizes the formation of singlet oxygen.^[2] It is responsible for the insecticidal activity of Tagetes minuta.^[3]

Together with derivatives of 2,2'-bithiophene, various substituted terthiophenes occur naturally. Examples include 5,5''-dichloro-α-terthiophene, 5-chloro-α-terthiophene, 5-acetyl α-terthiophene, and 5-carboxyl bithiophene.^[4]

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

See also

• Biphenyl
• Terphenyl
• Terpyridine

Notes and References

1. Smeets, B. J. J.. Meijer, R. H.. Meuldijk, J.. Vekemans, J. A. J. M.. Hulshof, L. A. . amp . Process Design and Scale-Up of the Synthesis of 2,2':5',2"-Terthienyl . Organic Process Research & Development . 2003 . 7 . 1 . 10–16 . 10.1021/op020044n .
2. Ciofalo, M. . Ponterini, G. . Generation of singlet oxygen by 2,2':5',2"-terthiophene and some of its derivatives . Journal of Photochemistry and Photobiology A . 1994 . 83 . 1 . 1–6 . CODEN: JPPCEJ . 1010-6030 . 10.1016/1010-6030(94)03802-3 .
3. Perich . M. J. . Wells . C. . Bertsch . W. . Tredway . K. E. . Isolation of the insecticidal components of Tagetes minuta (Compositae) against mosquito larvae and adults . Journal of the American Mosquito Control Association . 11 . 3 . 307–310 . 1995 . 8551298.
4. Liu, Y. . Ye, M. . Guo, H. Z. . Zhao, Y. Y. . Guo, D. A. . New thiophenes from Echinops grijisii . Journal of Asian Natural Products Research . 2002 . 4 . 3 . 175–178 . CODEN: JANRFI . 1028-6020 . 12118504 . 10.1080/1028602021000000071 . 41384356 .