- Synthesis of α-Thiophene Oligomers via 1,3-Butadiynes
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Individual oligomers possessing thiophenes linked by their 2- and 5-positions are conveniently prepared via 1,3-butadiynes.These can be prepared in good yield by the Glaser symmetrical coupling of thienylacetylenes.Following the cyclization of the 1,3-butadiyne unit into a thiophene with sodium sulfide, an oligomer possessing an odd number of thiophene rings is obtained.Oligomers with an even number of rings are accessible from unsymmetrical butadiynes obtained either by the Cadiot-Chodkiewicz procedure, utilizing an odd and an even precursor, or by an organoborane co upling procedure.
- Kagan, Jacques,Arora, Sudershan K.
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- Comprehensive evaluation of the absorption, photophysical, energy transfer, structural, and theoretical properties of ct-oligothiophenes with one to seven rings
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A large basis set of ct-oligothiophenes with two to seven rings (a.2-a.7), also including thiophene, al, have been investigated in five solvents regarding absorption, fluorescence and phosphorescence, quantum yields of fluorescence (Φ) and triplet formation (0r), lifetimes of fluorescence and the triplet state, quantum yields of singlet oxygen production (c is small, ff F is approximately constant while Arise decreases significantly from a.2 to aJ. The decrease is A'isc is believed to arise from a decrease in matrix elements of the type (1cr|H'|3W|). The essential lack of phosphorescence is assigned as originating from inter-ring twisting mode coupling between TI and SQ. Triplet energy transfer to 3Oa to produce 'Oi is highly efficient for a.2-o5. Based on all data, the first an representative of a-polythiophene is a5.
- Becker, Ralph S.,De Seixas Melo,Macanita, Antonio L.,Eliseil, Fausto
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- Facilitated synthesis of functional oligothiophenes for application in thin film devices and live cell imaging
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This paper describes recent developments in the synthesis of ultrapure functional oligothiophene-based materials taking advantage of enabling techniques such as microwave/ultrasound irradiation and chitosan-supported palladium catalysts. Examples showing how ultrapure oligothiophenes self-organize in order to optimize charge transport in thin film devices and fluorescence emission inside living cells are reported.
- Dimaria, Francesca,Barbarella, Giovanna
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p. 627 - 637
(2014/01/06)
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- Synthesis of functionalized thiophenes and oligothiophenes by selective and iterative cross-coupling reactions using indium organometallics
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The synthesis of unsymmetrical 2,5-disubstituted thiophenes by selective and sequential palladium-catalyzed cross-coupling reactions of indium organometallics with 2,5-dibromothiophene is reported. Following an iterative coupling sequence, α-oligothiophenes were synthesized in good yields and with high atom economy.
- Montserrat Martinez,Pena-Lopez, Miguel,Sestelo, Jose Perez,Sarandeses, Luis A.
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experimental part
p. 3892 - 3898
(2012/06/04)
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- Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira-Glaser cyclization sequence
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Based upon a consecutive one-pot Sonogashira-Glaser coupling-cyclization sequence a variety of 2,5-di(hetero)arylthiophenes were synthesized in moderate to good yields. A single Pd/Cu-catalyst system, without further catalyst addition, and easily available, stable starting materials were used, resulting in a concise and highly efficient route for the synthesis of the title compounds. This novel pseudo five-component synthesis starting from iodo(hetero)arenes is particularly suitable as a direct access to well-defined thiophene oligomers, which are of peculiar interest in materials science.
- Urselmann, Dominik,Antovic, Dragutin,Mueller, Thomas J. J.
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p. 1499 - 1503
(2011/12/22)
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- Using the nitro group to induce p-stacking in terthiophenes
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A new synthetic route to mononitrated oligothiophenes is described, as well as the preparation of halogenated derivatives (Br, I) thereof. An unusual deep red colour is observed and explained, with the aid of DFT calculations, as arising from a significant quinoidal contribution to the molecular structure. The crystal structures of two compounds, H(C4H2S) 3NO2 and Br(C4H2S) 3NO2, are presented. Both compounds have planar sheets held together by intermolecular short contacts (hydrogen bonds and, for the latter, NO2...Br interactions); the sheets do not directly superimpose, so the effect of the π-stacking is not maximized. Solid-state fluorescence and extended-Hueckel band-structure calculations are also presented for these materials.
- Sears, Wendy A.,MacKinnon, Craig D.,Mawhinney, Robert C.,Sinnemaki, Lauren C.,Johnson, Matthew J.,Winter, A. John,Robertson, Craig M.
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body text
p. 309 - 317
(2010/07/09)
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- Synthesis and photovoltaic properties of formyl end-capped oligothiophenes
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For the purpose of developing novel photovoltaic materials, 5,5″-biformyl-2,2′:5′,2″-terthiophene (OHC-3T-CHO) and 5,5″-biformyl-2,2′:5′,2″:5″,2?:5?, 2″″-q-uinquethiophene (OHC-5T-CHO) were synthesized. The photovoltaic properties of OHC-3T-CHO and OHC-5T-CHO were studied. We have fabricated two flexible organic photovoltaic devices using OHC-3T-CHO, OHC-5T-CHO, and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA). The PET-ITO (indium tin oxides coated with polyethylene terephthalate)/OHC-3T-CHO/ PTCDA/Al device has an open circuit voltage (Voc) of 1.12V, and photoelectric conversion efficiency (PCE) of 1.00%, whereas the PET-ITO/OHC-5T-CHO/PTCDA/Al device has a Voc of 1.78V and PCE of 1.08%. Both devices have high Voc (1.12V and 1.78V). It is possible that intermolecular hydrogen bonding between the -CHO group of OHC-nT-CHO and the carboxylic dianhydride of PTCDA enhanced the efficiency by promoting forward interfacial electron transfer.
- Jiang, Chuanyu,Liu, Ping,Deng, Wenji
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experimental part
p. 2360 - 2369
(2009/11/30)
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- Solution-phase microwave-assisted synthesis of unsubstituted and modified α-quinque- and sexithiophenes
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The facile synthesis of poorly soluble unsubstituted and modified α-quinque- and sexithiophenes under microwave irradiation in the liquid phase is described. The use of microwave irradiation allowed these compounds to be prepared in a few minutes and at high yields by means of the Suzuki cross-coupling reaction. Unsubstituted sexithiophene was obtained in 10 min via the one-pot borylation/Suzuki reaction, purified according to a very simple procedure, and isolated in 84% yield. The efficient synthesis of two new methylated quinque- and sexithiophenes displaying liquid crystalline properties is reported. A new microwave-assisted methodology for the conversion of aldehyde-terminated quinque- and sexithiophenes into the corresponding cyano derivatives is also described. The use of microwaves was extended to the Sonogashira coupling reaction and found to be very effective in the preparation of a quinquethiophene containing acetylenic spacers. The electronic and optical characterization of this compound is reported and discussed in relation to that of unsubstituted quinquethiophene.
- Melucci,Barbarella,Zambianchi,Di Pietro,Bongini
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p. 4821 - 4828
(2007/10/03)
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- Solvent-free, microwave-assisted synthesis of thiophene oligomers via suzuki coupling
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The purpose of this study was to obtain a rapid, efficient, and environmentally friendly methodology for the synthesis of highly pure thiophene oligomers. The solvent-free, microwave-assisted coupling of thienyl boronic acids and esters with thienyl bromides, using aluminum oxide as the solid support, allowed us to rapidly check the reaction trends on changing times, temperature, catalyst, and base and easily optimize the experimental conditions to obtain the targeted product in fair amounts. This procedure offers a novel, general, and very rapid route to the preparation of soluble thiophene oligomers. Thus, for example, quaterthiophene was obtained in 6 min by reaction of 2-bromo-2,2′-bithiophene with bis(pinacolato)diboron (isolated yield 65%), whereas quinquethiophene was obtained in 11 min by reaction of dibremoterthiophene with thienylboronic acid (isolated yield 74%). The synthesis of new chiral 2,2′-bithiophenes is reported. The detailed analysis of the byproducts of some reactions allowed us to elucidate a few aspects of reaction mechanisms. While the use of microwaves proved to be very convenient for the coupling between conventional thienyl moieties, the same was not true for the coupling of thienyl rings to thienyl-S,S-dioxide moieties. Indeed, in this case, the targeted product was obtained in low yields because of the competitive, accelerated, Diels-Alder reaction that affords a variety of condensation products.
- Melucci, Manuela,Barbarella, Giovanna,Sotgiu, Giovanna
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p. 8877 - 8884
(2007/10/03)
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- Convenient synthesis of α-terthienyl and α-quinquethienyl via a Friedel-Crafts route
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Thiophene and bithiophene are converted into 1,4-bis(2-thienyl)-1,4-butanedione and the corresponding bis(bithienyl) substituted diketone, respectively, by acylation with succinyl chloride/aluminum chloride in dichloromethane or 1,2-dichloroethane. Reaction of the diketones with Lawesson's reagent gives 2,2': 5',2'-terthiophene or 2,2': 5',2'': 5'',2'': 5''',2''''-quinquethiophene (α-terthienyl or α-quinquethienyl) in high yields. Attempted acylation of α-terthienyl leads to 5,5-bis[5-(2,2'' : 5',2'-terthienyl)]tetrahydrofuran-2-one. As a side-product of the Friedel-Crafts acylation of thiophene a new indigo-like blue dye with α-quaterthienyl framework is isolated.
- Merz,Ellinger
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p. 462 - 464
(2007/10/02)
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- Radical Cations and Anions from Some Simple Polythiophenes: an ESR Investigation
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The radical cations and anions of the four lower oligomers of thiophene have been generated and characterized by means of ESR spectroscopy, with the exception of bi- and quinque-thienyl radical cations. cis-trans isomerism about the interannular bonds, similar to that previously reported for the 2,2'-dithienyl radical anion, has been observed for terthienyl cation and anion radicals, while no direct evidence of such isomerism could be obtained for quaterthienyl and quinquethienyl.
- Alberti, Angelo,Favaretto, Laura,Seconi, Giancarlo,Pedulli, Gian Franco
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p. 931 - 935
(2007/10/02)
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- Thiophene Oligomers: Synthesis and Characterization
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The series of thiophene oligomers from bithienyl to α-sexithienyl has been synthesized according to the methods reported in the literature and some variation introduced by us.UV-visible, FT-IR, 13C-nmr and mass spectra of thiophene oligomers have been recorded and also cyclic voltammograms.Results are compared with data available in literature and are discussed in terms of conjugation length and coplanarity.Keywords: thiophene oligomers, 2,5-thienylene oligomers, 13C-nmr, FT-IR, spectroscopy
- Martinez, F.,Voelkel, R.,Naegele, D.,Naarmann, H.
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p. 227 - 232
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF 2,5-THIENYLENE OLIGOMERS; SOME OF THEIR SPECTROSCOPIC AND ELECTROCHEMICAL PROPERTIES
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Key words: 2,5-Thienylene oligomers, UV spectra, oxidation potentials, cyclic voltammetry.A convenient synthesis of a number of oligomeric thiophenes and oligomeric methyl-, and ethyl-substituted thiophenes as bulding blocks for novel conducting polymers is reported.The synthesis is based on a NiCl2(dppp) (dppp=Ph2PCH2CH2CH2PPh2) catalyzed coupling reaction between appropriately substituted bromothiophenes and Grignard compounds derived of them.The λmax of the UV spectra of the unsubstituted oligomeric thiophenes increases, as expected, with the number of thiophene units in the oligomers.Also, as expected, the oxidation potential Eox of these compounds decreases with increasing the number of thiophene units.In the series of the methyl- or ethyl-substituted oligomeric thiophenes such a clear cut relationship is not observed.This behavior is discussed on the basis of diminishing coplanarity due to steric hindrances by the alkyl groups in the 3,3'-positions, which results in a blue shift of the λmax of the UV spectra and decreased stability of the radical cation formed upon electrooxidation, manifesting itself by a higher oxidation potential.
- Pham, Chiem Van,Burkhardt, A.,Shabana, R.,Cunningham, David D.,Mark, Harry B.,Zimmer, Hans
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p. 153 - 168
(2007/10/02)
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- PREPARATION OF α-QUINQUE- AND α-SEPTITHIOPHENES AND THEIR POSITIONAL ISOMERS
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α-Quinque- and α-septithiophenes were synthesized in four steps starting from α-bi- and α-terthiophenes, respectively.One of positional isomers of each oligothiophene described above is also synthesized.
- Nakayama, Juzo,Nakamura, Yoichi,Murabayashi, Shigeru,Hoshino, Masamatsu
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p. 939 - 942
(2007/10/02)
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- THE SYNTHESIS OF ALPHA-THIOPHENE OLIGOMERS VIA ORGANOBORANES
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Oligomers containing from 2 to 6 thiophene units attached by their 2 and 5 positions were synthesized unambiguously by iodine oxidation of a suitable ate complex obtained by stepwise reactions of 9-BBN with methanol, a 2-lithiothiophene, boron trifluoride etherate, and a second 2-lithiothiophene.This is a one-pot procedure, carried out under nitrogen between -80 deg C and 0 deg C.
- Kagan, Jacques,Arora, Sudershan K.
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p. 4043 - 4046
(2007/10/02)
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