- Synthesis and mesomorphic behavior of novel liquid-crystalline thiophene derivatives
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A new class of thiophene-based cholesteryl and ferrocenyl derivatives was synthesized and characterized by common analytical techniques. Liquid-crystalline properties were investigated by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). Thiophene-based cholesteryl derivatives show homeotropic liquid-crystalline phase sequence crystal → smectic A → cholesteric → isotropic, whereas the ferrocenyl derivative is nonmesomorphic. The effects of thiophene ring, terminal group, and length of the polymethylene spacers on the mesomorphic behavior are discussed. Copyright Taylor & Francis Group, LLC.
- Majumdar,Mondal, Shovan,Ghosh, Tapas
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- Design and Applications of a SO2 Surrogate in Palladium-Catalyzed Direct Aminosulfonylation between Aryl Iodides and Amines
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A new SO2 surrogate is reported that is cheap, bench-stable, and can be accessed in just two steps from bulk chemicals. Essentially complete SO2 release is achieved in 5 minutes. Eight established sulfonylation reactions proceeded smoothly by ex situ formation of SO2 by utilizing a two-chamber system in combination with the SO2 surrogate. Furthermore, we report the first direct aminosulfonylation between aryl iodides and amines. Broad functional group tolerance is demonstrated, and the method is applicable to pharmaceutically relevant substrates, including heterocyclic substrates.
- Jia, Xiuwen,Kramer, S?ren,Skrydstrup, Troels,Lian, Zhong
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supporting information
p. 7353 - 7359
(2021/02/26)
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- Isomeric effect of fluorene-based fused-ring electron acceptors to achieve high-efficiency organic solar cells
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Acceptor-donor-acceptor (A-D-A) non-fullerene electron acceptors (NFEAs) using ladder-type donor structures have become the dominant n-type materials for achieving high-efficiency OSCs. In this work, two isomeric fluorene-based ladder-type structures FCTT (TT-C-F-C-TT) and FTCT (T-C-TFT-C-T) have been designed and synthesized. These two isomeric donors with the different fused-ring arrangement, molecular geometry, and side-chain placement were end-capped with the FIC acceptors to form two NFEAs FCTT-FIC and FTCT-FIC isomeric materials. Compared to FTCT-FIC using the thiophene (T)-terminal donor, FCTT-FIC with the thienothiophene (TT)-terminal donor has more evenly distributed side chains on both sides of the backbone and less steric hindrance near the FIC acceptors, which enables stronger antiparallel π-π packing among the end-groups to create a channel for efficient electron transport, as evidenced by the thin-film GIWAXS measurements. FCTT-FIC displayed a larger optical bandgap and deeper-lying energy levels than its FTCT-FIC isomer. Compared to the PBDB-T:FTCT-FIC device, the PBDB-T:FCTT-FIC device showed a higher PCE of 10.32% with an enhanced Jsc of 19.63 mA cm-2 and an FF of 69.14%. A PM6:FCTT-FIC device using PM6 as a p-type polymer achieved the highest PCE of 12.23%. By introducing PC71BM as the second acceptor to enhance the absorption at shorter wavelengths, optimize the morphology and facilitate electron transport, the ternary-blend PM6:FCTT-FIC:PC71BM (1 : 1 : 0.5 in wt%) device yielded the highest PCE of 13.37% with a Voc of 0.92 V, a higher Jsc of 19.86 mA cm-2, and an FF of 73.2%. This result demonstrated that the TT-terminal ladder-type donor is generally a better molecular design than the corresponding T-terminal ladder-type isomer for the development of new A-D-A NFEAs.
- Cao, Fong-Yi,Cheng, Yen-Ju,Huang, Po-Kai,Su, Yen-Chen,Xue, Yung-Jing
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supporting information
p. 5315 - 5322
(2020/03/19)
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- From Red to Green Luminescence via Surface Functionalization. Effect of 2-(5-Mercaptothien-2-yl)-8-(thien-2-yl)-5-hexylthieno[3,4- c]pyrrole-4,6-dione Ligands on the Photoluminescence of Alloyed Ag-In-Zn-S Nanocrystals
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A semiconducting molecule containing a thiol anchor group, namely 2-(5-mercaptothien-2-yl)-8-(thien-2-yl)-5-hexylthieno[3,4-c]pyrrole-4,6-dione (abbreviated as D-A-D-SH), was designed, synthesized, and used as a ligand in nonstoichiometric quaternary nanocrystals of composition Ag1.0In3.1Zn1.0S4.0(S6.1) to give an inorganic/organic hybrid. Detailed NMR studies indicate that D-A-D-SH ligands are present in two coordination spheres in the organic part of the hybrid: (i) inner in which the ligand molecules form direct bonds with the nanocrystal surface and (ii) outer in which the ligand molecules do not form direct bonds with the inorganic core. Exchange of the initial ligands (stearic acid and 1-aminooctadecane) for D-A-D-SH induces a distinct change of the photoluminescence. Efficient red luminescence of nanocrystals capped with initial ligands (λmax = 720 nm, quantum yield = 67%) is totally quenched and green luminescence characteristic of the ligand appears (λmax = 508 nm, quantum yield = 10%). This change of the photoluminescence mechanism can be clarified by a combination of electrochemical and spectroscopic investigations. It can be demonstrated by cyclic voltammetry that new states appear in the hybrid as a consequence of D-A-D-SH binding to the nanocrystals surface. These states are located below the nanocrystal LUMO and above its HOMO, respectively. They are concurrent to deeper donor and acceptor states governing the red luminescence. As a result, energy transfer from the nanocrystal HOMO and LUMO levels to the ligand states takes place, leading to effective quenching of the red luminescence and appearance of the green one.
- Kowalik, Patrycja,Bujak, Piotr,Wróbel, Zbigniew,Penkala, Mateusz,Kotwica, Kamil,Maroń, Anna,Pron, Adam
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supporting information
p. 14594 - 14604
(2020/10/09)
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- Utilizing Difluorinated Thiophene Units to Improve the Performance of Polymer Solar Cells
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While there are numerous approaches to functionalize conjugated polymers for organic solar cells (OSCs), one widely adopted approach is fluorination. Of the many different locations for fluorination, one of the least studied is the conjugated linker which connects the donor and acceptor moieties; further, all existing reports primarily explore monofluorinated thiophene units. Herein, we synthesize and compare two conjugated polymers, HTAZ and DFT-HTAZ, which have different thiophene linkers. In HTAZ, a bare thiophene unit connects the donor and acceptor moieties, while DFT-HTAZ utilizes difluorinated thiophene (DFT) linkers. These polymers serve as the model system to explore the impact of DFT units in OSCs; additionally, this is the first publication to investigate polymers containing DFT units paired with non-fullerene acceptors. Compared to HTAZ, the incorporation of the DFT units maintained the optical properties while lowering the energy levels by a0.4 eV, which allowed for a much improved Voc value of a1 V. Importantly, when compared with the appropriate non-fullerene acceptor, DFT-HTAZ:ITIC-Th1 blends reached an efficiency of a10%, which is nearly 3× that of the nonfluorinated HTAZ. As most OSC polymers have thiophene linkers, using DFT units could serve as a proficient method to increase OSC performance in many polymer systems, especially those that do not have locations for functionalization on the acceptor moiety.
- Rech, Jeromy J.,Yan, Liang,Peng, Zhengxing,Dai, Shuixing,Zhan, Xiaowei,Ade, Harald,You, Wei
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p. 6523 - 6532
(2019/09/30)
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- Efficient synthesis of 2,5-dicarbonyl derivatives of 3,4-ethylenedithiothiophene (EDTT) via addition-elimination reaction
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Derivatives of 3,4-ethylenedithiothiophene (EDTT) are reported starting from tetrabromothiophene. Selective 2,5-dilithiation followed by reaction with a range of aldehydes gives diols as mixtures of diastereomers. Only the 2 and 5 positions in thiophene react leaving the 3,4-bromides for further elaboration. The diols are oxidised to their corresponding diketones using activated MnO2. Reaction with 1,2-ethanedithiol, by addition-elimination, provides access to novel monomers for the preparation of conjugated copolymers of 3,4-ethylenedithiothiophene (EDTT). A range of these monomers can be attained by applying the synthesis of a series of ketones applicable to further synthesis of π-extended thiophene-based organic semiconductors. Finally, this new route was compared to 3,4-ethylenedioxythiophene (EDOT) dialdehyde derivatives synthesised by an alternative to literature chemistry.
- Al-jumaili, Mustafa A-jabbar,Woodward, Simon
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p. 5847 - 5852
(2017/09/09)
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- Organic Dye and Dye-Sensitized Solar Cell
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PURPOSE: An organic dye, photoelectric diode including the same and dye-sensitized solar battery are provided to have an absorbing band in long wavelength. CONSTITUTION: An organic dye is represented by chemical formula 1. A photoelectric diode includes porous oxide semiconductor membrane which includes the organic dye. A dye-sensitized solar cell comprises a first electrode, a second electrode which is formed on one side of the first electrode and includes a light absorptive layer, and electrolyte buried in a space between the first and second electrodes.
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Paragraph 0204-0210
(2018/02/10)
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- BLUE ELECTROCHROMIC COMPOUND, PREPARATION METHOD AND SUBASSEMBLY THEREOF
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One class of blue thiophene electrochromic compounds include 3,4-(2,2-bis(2-oxo-3-phenylpropyl))propylenedioxythiophene, 3,4-(2,2-bis(2-oxo-3-phenylbutyl))propylenedioxythiophene, and 3,4-(2,2-bis(2-oxo-3-phenylamyl))propylenedioxythiophene. The thiophene electrochromic compounds can change color between blue and transparency. The thiophene compounds can be electropolymerized on the surface of the ITO glass to form a film. The film has characteristics of low driving voltage (within ±1V), fast response time, and large transmittance difference between colored-state and bleached-state (up to 77.5%). The thiophene electrochromic compounds can be used in the electrochromic window, rearview mirror, electrochomeric display, and the like.
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Paragraph 0058; 0059
(2016/10/04)
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- ORGANIC COMPOUND AND ORGANIC LIGHT EMITTING DIODE DEVICE INCLUDING THE SAME
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The present invention relates to a novel organic compound and an organic light emitting device using the same, and more specifically, to a novel organic compound which has electrical stability, high electrical transport ability and light emitting ability, and high glass transition temperature, and can prevent crystallization, and to an organic light emitting device using an organic layer including the same.COPYRIGHT KIPO 2015
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Paragraph 0197-0204
(2016/11/14)
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- Plasmonic hybrid nanotubes of fullerene C60-polythiophene-silver or gold nanoparticles: Fabrication and enhancement of the Raman scattering
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We determined the surface-enhanced Raman scattering of the plasmonic hybrid nanotubes of fullerene C60-polythiophene-Ag or Au nanoparticles (NPs) which were synthesized via the template-based electrocopolymerization of terthiophene-linked fullerene C60 and terthiophene-modified Ag NPs or Au NPs using a nanoporous alumina membrane as the template. The combination of plasmonic activity and chemical stability may allow for a variety of new applications.
- Yoshida, Ryusuke,Matsumura, Takuya,Nakahodo, Tsukasa,Fujihara, Hisashi
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supporting information
p. 15183 - 15186
(2014/12/11)
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- Robust PEDOT films by covalent bonding to substrates using in tandem sol-gel, surface initiated free-radical and redox polymerization
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Poly(3,4-ethylenedioxythiophene), PEDOT, films are used as antistatic coatings on electrically insulating substrates such as plastic and glass. A novel method for the synthesis of conducting PEDOT films on insulators relies on sol-gel chemistry to attach a di-Si(OEt)3 functionalized free radical initiator (AIBN) on oxidized surfaces, followed by: (a) attachment of 3,4-(vinylenedioxy)thiophene (VDOT: an analogue to EDOT susceptible to radical addition through its vinylenedioxy group); and, (b) oxidative (with FeCl 3) co-polymerization of surface-confined VDOT with 3,4-ethylenedioxythiophene (EDOT). In conjunction with classical photolithography, the method yields thin (~150 nm) yet dense, pinhole-free (confirmed electrochemically), hard (>6H), extremely adhesive (5B), patterned, highly conducting (52 mho cm-1) films. The process is applied mainly on glass but it works equally well on oxidized metal surfaces (aluminum, steel, Pt). Control studies related to "grafting from" with surface-confined AIBN were conducted by growing inexpensive poly(styrene) and poly(methylmethacrylate) films.
- Sadekar, Anand G.,Mohite, Dhairyashil,Mulik, Sudhir,Chandrasekaran, Naveen,Sotiriou-Leventis, Chariklia,Leventis, Nicholas
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p. 100 - 108
(2013/01/12)
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- Synthesis, electropolymerization and characterization of a cross-linked PEDOT derivative
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The synthesis of a novel electropolymerizable monomer, 2,2′,3, 3′-tetrahydro-2,2′-bithieno[3,4-b][1,4]dioxine (THBTD), based on two 3,4-ethylenedioxythiophene (EDOT) moieties connected through the ethylenedioxy bridge is reported. The new monomer paves the way for the development of cross-linked networks based on the EDOT moiety. Polymer films were electrogenerated from monomeric solutions by consecutive potential sweeps or by flow of constant anodic currents and the polymer structure was studied using FTIR. The relationship between the mass of the electrogenerated polymer (after reduction) and the polymerization charge gives the productivity of the consumed charge (mg C-1) while the charge stored and delivered by the films was determined by cyclic voltammetry getting the specific charge (C g -1). Simultaneously with the electroinitiated polymerization a chemical polymerization occurs around the electrode by monomer protonation giving protonated and no electroactive polymer chains. This chemical polymerization was followed in solution by UV-Vis spectroscopy using different conditions. Productivities and specific charges change with the conditions of synthesis in opposite directions. The voltammetric control presents a main redox couple (0.54/0.50 V) and a strong reduction process at -2.89 V that only can be reoxidized at more anodic potentials than 0.3 V as usual for charge trapping effects. EQCM studies indicate a remarkable difference between PEDOT and poly(THBTD). While poly(THBTD) shows a predominantly reversible anionic exchange during oxidation from the neutral state, the parent pristine PEDOT presents a mixed anionic and cationic exchange. Electrochromic color changes from an intense blue color of the oxidized film to a clear orange color in the reduced films as observed by in situ UV-Vis spectroscopy. Interestingly, the electrochromic changes in poly(THBTD) are opposed to those of PEDOT. Both thiophene derivative polymers present a similar thermal degradation at 305 and 314 °C, respectively.
- Arias-Pardilla, Joaquin,Gimenez-Gomez, Pablo A.,De La Pena, Alejandro,Segura, Jose L.,Otero, Toribio F.
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scheme or table
p. 4944 - 4952
(2012/06/18)
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- Synthesis of dibenzothiophenes and carbazoles by sequential 'tetra-fold heck/6 π-electrocyclization/dehydrogenation' reactions of tetrabromothiophene and tetrabromo-N-methylpyrrole
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Dibenzothiophenes and carbazoles were prepared by tetrafold Heck reactions of tetrabromothiophene and N-methyltetrabromopyrrole and subsequent 6π-electrocyclization and dehydrogenation. A number of reactions could be successfully carried out as domino reactions in only one synthetic step. Copyright
- Toguem, Serge-Mitherand Tengho,Knepper, Ingo,Ehlers, Peter,Dang, Tung T.,Patonay, Tamas,Langer, Peter
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scheme or table
p. 1819 - 1826
(2012/07/30)
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- Influence of electron delocalization in heterocyclic core systems on the electrochemical communication in 2,5-Di-and 2,3,4,5-tetraferrocenyl thiophenes, furans, and pyrroles
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A series of 2,5-di-and 2,3,4,5-tetraferrocenyl-substituted thiophenes, furans, and pyrroles were synthesized using the Negishi C,C cross-coupling protocol. The electronic and electrochemical properties of these compounds were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and in situ UV-vis/NIR spectroscopy. The molecular structures of 2,5-diferrocenyl furan and 2,3,4,5-tetraferrocenyl-1-methyl-1H-pyrrole in the solid state are discussed. The ferrocenyls could sequentially be oxidized giving two or four reversible responses for the appropriate di-or tetraferrocenyl-substituted heterocyclic molecules. The observed ΔE°′ values range between 186 and 450 mV. The NIR measurements confirm electronic communication as intervalence charge transfer (IVCT) absorptions were found in the corresponding mono-and in case of the tetraferrocenyl compounds also in the dicationic species. All compounds, except tetraferrocenyl thiophene (a class I system), were classified as class II systems according to Robin and Day. They show a linear relationship between ΔE°′ and the IVCT oscillator strength f which could be shown for the first time in organometallic chemistry. This was possible because the series of molecules exhibit analogous geometries and hence, similar electrostatic properties. This correlation was confirmed by electro-and spectro-electrochemical measurements. Within these studies a new approach for the estimation of the effective electron transfer distances r ab is discussed.
- Hildebrandt, Alexander,Schaarschmidt, Dieter,Claus, Ron,Lang, Heinrich
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body text
p. 10623 - 10632
(2011/12/13)
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- Synthesis and characterization of monomeric and polymeric Cu(II) complexes of 3,4-ethylenedioxythiophene-functionalized with cyclam ligand
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A functionalized EDOT derivative with 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand pendant to the ethylene bridge (4) and its complexes [M(4)(BF4)2], where M(II) = Cu(II), was prepared and characterized. Their electrochemical copolymerization with EDOT was studied. The electro-co-polymerized films were characterized by electrochemical methods, X-ray photoelectron spectroscopy and by X-ray fluorescence spectroscopy. The co-polymerization method was found to afford a good control of the metal concentration in the polymer matrix and represents a good technique for preparing electronically conductive polymers containing redox-active metal complexes.
- Velauthamurty, Kuhamoorthy,Higgins, Simon J.,Rajapakse, R.M. Gamini,Bandara,Shimomura, Masaru
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experimental part
p. 326 - 332
(2011/03/17)
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- Brominated thiophenes as precursors in the preparation of brominated and arylated anthraquinones
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Brominated anthraquinones can be synthesized directly from bromothiophenes when these are reacted with 1,4-naphthoquinones in the presence of meta-chloroperoxybenzoic acid. The bromoanthraquinones are versatile building blocks in the preparation of arylated anthraquinones and of extended π-systems with interspersed anthraquinone units.
- Thiemann, Thies,Tanaka, Yasuko,Iniesta, Jesus
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experimental part
p. 1013 - 1031
(2009/10/10)
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- First triazole-bridged unsymmetrical porphyrin dyad via click chemistry
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(Chemical Equation Presented) Click chemistry has been successfully applied in the synthesis of the first example of a triazole-bridged porphyrin dyad containing N2S2 porphyrin and N4 or ZnN 4 porphyrin subunits, and fluorescence study indicated a possibility of singlet-singlet energy transfer from the N4 or ZnN4 porphyrin subunit to the N2S2 porphyrin subunit.
- Punidha, Sokkalingam,Sinha, Jasmine,Kumar, Anil,Ravikanth, Mangalampalli
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p. 323 - 326
(2008/09/17)
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- Elastic and inelastic electron tunneling spectroscopy of a new rectifying monolayer
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Rectification of electrical current was observed in a Langmuir-Schaefer monolayer of fullerene-bis[ethylthio-tetrakis(3,4-dibutyl-2-thiophene-5-ethenyl) -5-bromo-3,4-dibutyl-2-thiophene] malonate, Au electrodes at room temperature (there are two regimes of asymmetry, at lower bias, i.e., between 0 and ±2 V, and at higher bias), and also between Pb and Al electrodes at 4.2 K. The latter experiment was coupled with second harmonic detection of the second derivative of the current with respect to voltage (d2I/dV 2). The d2I/dV2 spectrum shows intramolecular vibrations, and also two antisymmetric broad bands, centered at ±0.65 V, due to resonant electron tunneling between the Fermi level(s) of the electrodes and the lowest unoccupied molecular orbital of the molecule.
- Honciuc, Andrei,Metzger, Robert M.,Gong, Aijun,Spangler, Charles W.
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p. 8310 - 8319
(2008/02/09)
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- Metallic catalysts for chemo-, regio-and stereoselective reactions, and corresponding precursors
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Metallic catalysts of the general formula (I) and their precursors, suitable for chemo- regio- and stereoselective reactions, derived from ortho-bis-(1-phospholanyl)-heteroarenes. The new catalysts are characterized by the presence of two homomorphic phospholanic rings set in adjacent positions of an aromatic pentatomic heterocycle.
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- New regiosymmetrical dioxopyrrolo- and dihydropyrrolo-functionalized polythiophenes
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(Chemical Equation Presented) We present the synthesis of two N-alkylated poly(dioxopyrrolothiophene)s and two N-alkylated poly(dihydropyrrolothiophene)s with potential application in the field of conducting polymers. The polymers are synthesized from the corresponding 2,5-dibromothiophenes by an Ullmann-type polymerization and a Stille-type polymerization, respectively. The two N-alkylated poly(dihydropyrrolothiophene)s are the first examples of amino-functionalized polythiophenes built from regiosymmetrical thiophene monomers.
- Nielsen, Christian B.,Bjornholm, Thomas
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p. 3381 - 3384
(2007/10/03)
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- A new reaction of P4S10 and Lawesson's reagent; a new method for the synthesis of dithieno[3,2-b;2′,3′-d]thiophenes
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A new reaction of P4S10 and Lawesson's reagent for the synthesis of fused thiophenes has been uncovered. It has given easy access to the synthesis of derivatives of the technologically important heterocycle dithieno[3,2-b;2′,3′-d]thiophene, DTT. Electrochemical polymerization of one of the derivatives has been demonstrated.
- Ertas, Erdal,Ozturk, Turan
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p. 3405 - 3407
(2007/10/03)
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- Bridging nanogap electrodes by in situ electropolymerization of a bis(terthiophenylphenanthroline)ruthenium complex
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A novel complex containing a 3,8-bis[terthiophenyl-(1,10-phenanthroline)] ligand coordinated to [Ru(bpy)2] was synthesized and characterized by electrochemical and spectroscopic techniques. The complex was shown to be a suitable starting material for the electrode position of functionalized molecular wires between nanogap electrodes to generate stable molecular nanodevices. Temperature-dependent nonlinear I-V curves were obtained at 80-300 K. The material can also be deposited on indium tin oxide (ITO) to form compact electrochromic films at surface concentrations lower than ≈ 1 × 10 -8 mol cm2; however, a more loosely bond fibrous form is preferentially deposited at higher surface concentrations.
- Araki, Koiti,Endo, Hiroaki,Masuda, Gou,Ogawa, Takaji
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p. 3331 - 3340
(2007/10/03)
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- 4-[(4-(CARBOXYETHYL) PIPERIDINYL) METHYL] PYRROLIDINES AS MODULATORS OF CHEMOKINE RECEPTOR ACTIVITY
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3-Substituted pyrrolidines having a 4-carboxypiperidinylmethyl substituent on the 4-position of the ring are useful as modulators of chemokine receptor activity. In particular, these compounds are useful as modulators of the chemokine receptors CCR-3 and/or CCR-5.
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Page 31-32; 24
(2010/02/07)
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- 4(SPIROPIPERIDINYL)METHYL SUBSTITUTED PYRROLIDINES AS MODULATORS OF CHEMOKINE RECEPTOR ACTIVITY
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3-Substituted pyrrolidines having a spiropiperidinylmethyl substituent on the 4-position of the ring are useful as modulators of chemokine receptor activity. In particular, these compounds are useful as modulators of the chemokine receptors CCR-3 and/or CCR-5.
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- Synthesis of β-Thiophene-Substituted 21,23-Dithiaporphyrins
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β-Thiophene-substituted 21,23-dithiaporphyrins with substituents like methyl and phenyl groups were synthesized and characterized.
- Agarwal, Neeraj,Mishra, Sarada P.,Kumar,Ravikanth
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p. 744 - 745
(2007/10/03)
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- On the origin of optical activity in polythiophenes
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Optically active substituents attached as sidechain to π-conjugated polymers provide a particularly interesting and revealing tool to study the nanoscopic and mesoscopic supramolecular organization of π-conjugated polymers in general. Chiral substituents allow the properties of these polymers to be studied with circularly polarized light in both absorption and emission. Here we describe a comprehensive investigation on the structure and optical properties of poly{3,4-bis[(S)-2-methylbutoxy]thiophene} (PBMBT) as an example to elucidate the molecular origin of the chiroptical effects in chiral conjugated polymers. The chiral side chains of PBMBT induce very strong bisignate circular dichroism (CD) effects in the π-π* absorption when the polymer is in an aggregated phase. The anisotropy factor in absorption (g(abs)) is as high as 8 x 10-2. The photoluminescence of PBMBT aggregates is characterized by a very small stokes shift (90 meV) and exhibits circular polarization (CPL). The chiroptical properties in absorption and emission of PBMBT are associated with a high degree of intrachain and interchain order as they are present in aggregated phases but absent when the polymer chains are molecularly dissolved or in a melt. The observed CD and CPL effects are consistent with an exciton splitting between transition dipole moments in the excited state on different polymer chains. The strong optical activity associated with the π-π* transition of PBMBT is attributed to originate from a helical packing of predominantly planar chains, rather than from a helical intrachain conformation. As a result a detailed molecular description of the polythiophene morphology is obtained. (C) 2000 Elsevier Science B.V.
- Langeveld-Voss,Janssen,Meijer
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p. 285 - 301
(2007/10/03)
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- Synthesis, polymerization and characterization of substituted dithieno [3,4-b: 3',4'-d] thiophenes
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Chemical or electrochemical oxidation of substituted dithieno [3,4- b:3',4'-d]thiophenes provides polymers with defined regiochemical structures. These materials have lower bandgaps (0.7-0.9 eV) than the unsubstituted fused heteroarene. Potential cycling of the 1,3-dimethyl substituted polymer film shows repetitive p- and n-dopability. The chemically-prepared dioctyl analog is soluble in common solvents such as chloroform, dichloromethane and THF. However, overoxidation of the polymers at an electrode surface presents a limitation to the polymerization of substituted analogs of the parent fused heteroarene.
- Inaoka, Seiji,Collard, David M.
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p. 1719 - 1725
(2007/10/03)
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- Synthetic Applications of 3,4-Bis(trimethylsilyl)thiophene: Unsymmetrically 3,4-Disubstituted Thiophenes and 3.4-Didehydrothiophene
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3,4-Bis(trimethylsilyl)thiophene (1a) was synthesized by three routes: (a) 1,3-dipolar cycloaddition; (b) modification of 3,4-dibromothiophene; and (c) intermolecular thiazole-alkyne Diels-Alder reaction. 3,4-Bis(trimethylsilyl)thiophene (1a) can function as a versatile building block for the construction of unsymmetrically 3,4-disubstituted thiophenes utilizing its step wise regiospecific mono-ipso-substitution followed by palladium-catalyzed cross-coupling reactions. In this manner, thiophenes 15, 16, 17a-j, 19a,b, 20, 22a-c, 23a,b, 24a-d, 25a-c, and 27a-j were prepared. The thiophene-3,4-diyl dimer 28 and thiophene-3,4-diyl tetramer 29 were also realized by palladium-catalyzed self-coupling reaction of organoboroxines. The stannylthiophene 31, formed by conversion of the C-Si bond to a C-Sn bond via boroxine 26c underwent both carbonylative coupling and lithiation followed by quenching with electrophiles to afford unsymmetrically 3,4-disubstituted thiophenes 33 and 36a-c as well. Moreover, 3,4-bis(trimethylsilyl)thiophene (1a) can be used as the starting material for the generation of the highly strained cyclic cumulene 3,4-didehy-drothiophene (2), whose existence was substantiated by its trapping reaction with several alkenes.
- Ye, Xin-Shan,Wong, Henry N. C.
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p. 1940 - 1954
(2007/10/03)
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- Halogenation Using Quaternary Ammonium Polyhalides. XXXI. Halogenation of Thiophene Derivatives with Benzyltrimethylammonium Polyhalides
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The reactions of thiophene derivatives with benzyltrimethylammonium tetrachloroiodate, benzyltrimethylammonium tribromide, and benzyltrimethylammonium dichloroiodate in acetic acid or in acetic acid-zinc chloride under mild conditions gave chloro-, bromo-, and iodo-substituted thiophene derivatives, respectively, in satifactory yields.
- Okamoto, Tsuyoshi,Kakinami, Takaaki,Fujimoto, Hiroshi,Kajigaeshi, Shoji
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p. 2566 - 2568
(2007/10/02)
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- 3,4-Dibromothiophene from 2-Bromothiophene
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3,4-Dibromothiophene can be obtained in a reasonable yield by treating the readily available 2-bromothiophene with a mixture of equimolar amounts of sodamide and potassium tert-butoxide in liquid ammonia.
- Brandsma, L.,Verkruijsse, H.D.
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p. 2119 - 2122
(2007/10/02)
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- Bromothiophene Reactions. I. Friedel-Crafts Acylation
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Friedel-Crafts acylation of 2,5-dibromo- and 2,3,5-tribromothiophenes with different acyl chlorides and anhydrous aluminium trichloride has been studied.The reaction afforded a mixture of acyl derivatives and tetrabromothiophene.The results obtained suggest a mechanism which involves the formation of bromine cations in the reaction medium.Several products obtained in this reaction are described.
- Agua, M. J. del,Alvarez-Insua, A. S.,Conde, S.
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p. 1345 - 1347
(2007/10/02)
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