Terthiophene

Chembox new
Name = Terthiophene
ImageFile = Alpha-Terthiophene numbering.svg
ImageName = Terthiophene
IUPACName = 2,2':5',2"-terthiophene
OtherNames = α-Terthienyl
2,5-Di(2-thienyl)thiophene
Section1 = Chembox Identifiers
SMILES =
CASNo = 1081-34-1
RTECS = WZ9717750
Section2 = Chembox Properties
Formula = C₁₂H₈S₃
MolarMass = 248.39 g/mol
Appearance = pale yellow solid
Density = ? g/cm³, ?
Solubility = insoluble
MeltingPt = 93-95 °C
Section3 = Chembox Structure
CrystalStruct =
Dipole =
Section7 = Chembox Hazards
ExternalMSDS =
MainHazards = flammable
RPhrases =
SPhrases = 22-24/25
Section8 = Chembox Related
OtherCpds = Thiophene
polythiophene

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. [Smeets, B. J. J.; Meijer, R. H.; Meuldijk, J.; Vekemans, J. A. J. M.; Hulshof, L. A. "Process Design and Scale-Up of the Synthesis of 2,2':5',2"-Terthienyl" Organic Process Research & Development (2003), volume 7, pages 10-16.]

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, which is often lethal. [Ciofalo, Maurizio; Ponterini, Glauco. Generation of singlet oxygen by 2,2':5',2"-terthiophene and some of its derivatives. Journal of Photochemistry and Photobiology, A: Chemistry (1994), 83(1), 1-6. CODEN: JPPCEJ ISSN:1010-6030.] A variety of terthiophenes occur naturally, including 5,5"-dichloro-α-terthiophene, 5-chloro-α-terthiophene, 5-acetyl α-terthiophene, and 5-carboxyl bithiophene. [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), volume 4, pages 175-178. JANRFI ISSN:1028-6020.]

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

References