- Direct arylation as a synthetic tool for the synthesis of thiophene-based organic electronic materials
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The efficient synthesis of thiophene based organic electronic materials can be carried out in high yields using simple starting materials by employing palladium-catalyzed direct arylation. The direct arylation method was applied to the (formal) synthesis of ten molecules that have exhibited promise for applications as optoelectronic materials. The syntheses feature the following advantages over traditional cross-coupling techniques: (1) higher yields, (2) fewer synthetic operations, (3) lower catalyst loadings, and (4) does not employ organometallic intermediates. The advantages of direct arylation make it an ideal strategy for the synthesis of thiophene containing organic electronic materials.
- Schipper, Derek J.,Fagnou, Keith
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- Rodlike 4,6-diamino-1,3,5-triazine derivatives, effect of the core length on mesophase behavior and their application as LE-LCD device
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Three series of diaminotriazine derivatives with different core length have been synthesized, and the influence of the structural variation as well as the temperature on their mesophase behaviour were systematically investigated. With focus on the formation of CubI/Im3ˉm phase, multiple 2D/3D phases were discovered. Confirmed by polarized optical microscope, small/wide angle X-ray scattering, grazing incident small-angle X-ray scattering as well as molecular dynamics simulation, the results indicate that molecular curvature is critical to self-assembly structures. Moreover, the prerequisite for the formation of the CubI/Im3ˉm phase is intermediate molecular curvature on the surface of the micelle to allow the intercalation of the alkyl chains. Finally, the potentials for such compounds as light-emitting liquid crystal display (LE-LCD) device has been initially demonstrated.
- Tan, Xiaoping,Chang, Qing,Su, Fawu,Cao, Yu,Liu, Feng,Cheng, Xiaohong
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- Synthesis of an Air-Stable Pd(0) Catalyst Bearing Donor and Acceptor Phosphine Ligands
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We synthesized a new Pd(0) complex bearing π-acceptor ligands and a σ-donor ligand and confirmed that it exhibits high air stability and catalytic activity in direct arylation reactions. Moreover, stoichiometric reactions of the complex revealed that the σ-donor ligand does not dissociate from the Pd center.
- Kanbara, Takaki,Kuwabara, Junpei,Sato, Ryota
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supporting information
(2020/02/04)
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- Air-stable Pd(0) catalyst bearing dual phosphine ligands: a detailed evaluation of air stability and catalytic property in cross-coupling reactions
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We have synthesised an air-stable Pd(0) catalyst bearing donor and acceptor phosphine ligands (Complex1). This study revealed the long-term air stability and catalytic property of Complex1as a catalyst for cross-coupling reactions, where it was stable in air for eight months. DFT calculations revealed that the acceptor ligands in Complex1decreased the HOMO energy level, which provided the observed air stability. Complex1successfully served as a catalyst for direct C-H arylation reactions and Suzuki-Miyaura cross-coupling reactions, and catalysed the reaction of a relatively inactive substrate, 2-chrolopyridine, which could not be achieved by conventional, air-stable Pd(0) catalysts. Isolating the intermediates of the coupling reactions revealed that each intermediate possessed the donor ligand (PCy3), which was determined to be responsible for imparting the high catalytic activity exhibited by Complex1.
- Sato, Ryota,Kanbara, Takaki,Kuwabara, Junpei
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p. 12814 - 12819
(2020/10/02)
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- TRANSITION METAL-CONTAINING COMPOUND AND METHOD FOR PRODUCING THE SAME
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PROBLEM TO BE SOLVED: To provide a transition metal-containing compound having a catalytic activity equal to or higher than that of a conventional cross-coupling catalyst while having stability to air. SOLUTION: There is provided a transition metal-containing compound represented by the following formula (1). (wherein, M is at least one transition metal selected from groups 8 to 11 transition metals, A is an electron withdrawing monodentate ligand containing a ring structure or a branched structure, D is an electron-donating ligand, m and n are a coordination number to the transition metal of the ligand, respectively, m is an integer of 2 to 5, n is an integer of 1 to 2 and m>n. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0064-0066
(2020/06/05)
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- Liquid crystalline 2-thienyl-4,6-diamino-1,3,5-triazines exhibiting Im3m and Pm3n micellar cubic phases in an inverted sequence
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Two micellar cubic phases with different structures were observed for the first time in the order Im3m-Pm3n in a thermotropic phase sequence of 4,6-diaminotriazine terminated rod-like liquid crystals upon increasing alkyl chain length or rising temperatur
- Dai, Heng,Yang, Xueyan,Tan, Xiaoping,Su, Fawu,Cheng, Xiaohong,Liu, Feng,Tschierske, Carsten
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supporting information
p. 10617 - 10619
(2013/11/06)
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- Ligand-less palladium-catalyzed direct 5-arylation of thiophenes at low catalyst loadings
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Ligand-less Pd(OAc)2 provides a very efficient catalyst for the direct 5-arylation of thiophene derivatives. With this catalyst, a low palladium concentration (0.1-0.001 mol%) should be employed in order to obtain high yields of coupling products. At higher concentrations a fast formation of inactive "Pd black" generally occurs. Substrates/catalysts ratios up to 100000 can be employed with the most reactive aryl bromides. A very wide variety of functional groups is tolerated on both coupling partners. The major waste of this reaction is HBr associated with KOAc. Therefore this procedure is more economically and environmentally attractive than the traditional cross-coupling procedures employing organometallic derivatives.
- Roger, Julien,Pozgan, Franc,Doucet, Henri
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experimental part
p. 425 - 432
(2010/04/22)
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- Direct arylation of thiophenes via palladium-catalysed C-H functionalisation at low catalyst loadings
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Palladium associated with cis,cis,cis-1,2,3,4- tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) was found to promote the direct 2-arylation of a variety of thiophene derivatives via C-H functionalisation in good yields using very low catalyst loadings. Electron-deficient, electron-excessive or sterically-congested aryl bromides are tolerated. Moreover, several substituents on the aryl bromide or thiophene derivatives such as acetyl, formyl, nitrile, nitro, ester, methoxy, fluoro or trifluoromethyl are tolerated. The most reactive aryl bromides were coupled with thiophenes derivatives using as little as 0.1-0.01 mol% catalyst.
- Battace, Ahmed,Lemhadri, Mhamed,Zair, Touriya,Doucet, Henri,Santelli, Maurice
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p. 2507 - 2516
(2008/09/19)
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- Liquid crystalline alkenyl compounds incorporating an heterocyclic five-membered ring
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Liquid crystal mixtures comprising at least one of the compounds of formula (I) containing a heterocyclic five-membered ring and with a carbon-carbon double bond in the termninal group are new. RJ=CnH2n+1CH=CHCmH2mZ1; n=1-5; m=0-5; and q=0, 1 or 2; A1 and
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- Nematic 2,5-disubstituted thiophenes
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A large number of new liquid crystals incorporating the 2,5-disubstituted thiophene ring have been prepared and their mesomorphic behaviour studied in order to systematically investigate the correlation between the molecular structure and mesomorphism of thiophene derivatives with different shapes, polarisability and polarity. As a consequence of these investigations we have prepared a new class of liquid crystals incorporating a 2,5-disubstituted thiophene ring and a conjugated trans-carbon-carbon double bond in the terminal chain. These novel thiophene derivatives are the first liquid crystals incorporating a 2,5-disubstituted thiophene ring to exhibit a nematic phase at room temperature. This enables the flexoelectric coefficients of a bent-shaped molecule to be measured directly and at room temperature for the first time to the authors' knowledge. Many of these new thiophenes exhibit a high birefringence and a high nematic clearing point and are of potential use as components of nematic mixtures in LCDs.
- Campbell, Neil L.,Duffy, Warren L.,Thomas, Gareth I.,Wild, Janine H.,Kelly, Stephen M.,Bartle, Kevin,O'Neill, Mary,Minter, Vicky,Tuffin, Rachel P.
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p. 2706 - 2721
(2007/10/03)
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- Extension of the Heck reaction to the arylation of activated thiophenes
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The direct arylation of activated thiophenes was accomplished in moderate to good yields using a Heck-type reaction with the mixture of Pd(OAc)2 and n-Bu4NBr as a catalytic system. This new arylation method is applied to different derivatives and has proved to be compatible with sensitive functional groups. Furthermore, the substituent nature and position on the thiophene moiety influence the cross coupling. In particular the substitution is regiospecific when the heterocycle is substituted at position 2 with an electron withdrawing group.
- Lavenot,Gozzi,Ilg,Orlova,Penalva,Lemaire
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- Direct thiophene arylation catalysed by palladium
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Direct thiophene arylation using a Heck-type reaction with Pd(OAc)2/NBu4Br as catalytic system is reported. Reactions with 2- and 3-substituted thiophenes have shown that substituent nature and position influence the cross-coupling.
- Gozzi, Christel,Lavenot, Laurence,Ilg, Kerstin,Penalva, Vincent,Lemaire, Marc
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p. 8867 - 8870
(2007/10/03)
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