- Effect of a Pendant Acceptor on Thermally Activated Delayed Fluorescence Properties of Conjugated Polymers with Backbone-Donor/Pendant-Acceptor Architecture
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Three sets of conjugated polymers with backbone-donor/pendant-acceptor architectures, named PCzA3PyB, PCzAB2Py, and PCzAB3Py, are designed and synthesized. The three isomeric benzoylpyridine-based pendant acceptor groups are 6-benzoylpyridin-3-yl (3PyB), 4-((pyridin-2-yl)carbonyl)phenyl (B2Py) and 4-((pyridin-3-yl)carbonyl)phenyl (B3Py), whereas the identical backbone consists of 3,6-carbazolyl and 2,7-acridinyl rings. One acridine ring and each acceptor group constitute a definite thermally activated delayed fluorescence (TADF) unit, incorporated into the main chain of the polymers through the 2,7-position of the acridine ring with the varied content. All of the polymers display legible TADF features with a short microsecond-scale delayed lifetime (0.56–1.62 μs) and a small singlet/triplet energy gap (0.10–0.19 eV). Progressively redshifted emissions are observed in the order PCzAB3Py, PCzA3PyB, and PCzAB2Py owing to the different substitution patterns of the pyridyl group. Photoluminescence quantum yields can be improved by regulating the molar content of the TADF unit in the range 0.5–50 %. The non-doped organic light-emitting devices (OLEDs) fabricated by solution-processing technology emit yellow-green to orange light. The polymers with 5 mol % of the TADF unit exhibit excellent comprehensive electroluminescence performance, in which PCzAB2Py5 achieves a maximum external quantum efficiency (EQE) of 11.9 %, low turn-on voltage of 3.0 V, yellow emission with a wavelength of 573 nm and slow roll-off with EQE of 11.6 % at a luminance of 1000 cd m?2 and driving voltage of 5.5 V.
- Yang, Yike,Li, Kuofei,Wang, Chenxu,Zhan, Hongmei,Cheng, Yanxiang
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supporting information
p. 574 - 581
(2019/02/05)
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- Room Temperature Metal-Catalyzed Oxidative Acylation of Electron-Deficient Heteroarenes with Alkynes, Its Mechanism, and Application Studies
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Herein, we report an original one-step, simple, room-temperature, regioselective Minisci reaction for the acylation of electron-deficient heteroarenes with alkynes. The method has broad functional group compatibility and gives exclusively monoacylated products in good to excellent yields. The mechanistic pathway was analyzed based on a series of experiments confirming the involvement of a radical pathway. The 18O-labeling experiment suggested that water is a source of oxygen in the acylated product, and head space GC-MS experiment shows the C-C cleavage occurs via release as CO2.
- Sharma, Shweta,Kumar, Mukesh,Vishwakarma, Ram A.,Verma, Mahendra K.,Singh, Parvinder Pal
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p. 12420 - 12431
(2018/10/20)
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- Facile one-pot synthesis of [1,2,3]triazolo[1,5-a]pyridines from 2-acylpyridines by copper(II)-catalyzed oxidative N-N bond formation
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An efficient and simple method for the synthesis of various [1,2,3]triazolo[1,5-a]pyridines has been established. The method involves a copper(II)-catalyzed oxidative N-N bond formation that uses atmospheric oxygen as the terminal oxidant following hydrazonation in one pot. The use of ethyl acetate as the solvent dramatically promotes the oxidative N-N bond-formation reaction and enables the application of oxidative cyclization in the efficient one-pot reaction. A mechanism for the reaction was proposed on the basis of the results of a spectroscopic study. In the same pot: [1,2,3]Triazolo[1,5-a] pyridines are synthesized from the corresponding 2-acylpyridines by a one-pot method, consisting of hydrazonation followed by oxidative cyclization through copper(II)-catalyzed N-N bond formation (see scheme).
- Hirayama, Tasuku,Ueda, Satoshi,Okada, Takahiro,Tsurue, Norihiko,Okuda, Kensuke,Nagasawa, Hideko
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p. 4156 - 4162
(2014/04/17)
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- 5-Bromo-2-pyridylzinc reagent; Direct preparation and its coupling reactions
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A facile synthetic route to the direct preparation of 5-bromo-2-pyridylzinc iodide has been developed. Treatment of 5-bromo-2-iodopyridine with active zinc gave rise to the selective oxidative addition to C-I bond under mild conditions. The resulting orga
- Rieke, Reuben D.,Kim, Seung-Hoi
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supporting information; experimental part
p. 244 - 247
(2011/02/25)
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- TMSCH2Li and TMSCH2Li-LiDMAE: Efficient reagents for noncryogenic halogen-lithium exchange in bromopyridines
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(Chemical Equation Presented) TMSCH2Li and TMSCH 2Li-LiDMAE have been used efficiently for bromine-lithium exchange in 2-bromo-, 3-bromo-, and 2,5-dibromopyridines under noncryogenic conditions, while low temperatures (-78 to -100°C) are always needed with n-BuLi. The aminoalkoxide LiDMAE induced a remarkable C-2 selectivity with 2,5-dibromopyridines in toluene at 0°C, which was unprecedented at such a temperature. The lithiopyridines were successfully reacted witb electrophiles also under noncryogenic conditions giving the expected adducts in good yields.
- Doudouh, Abdelatif,Woltermann, Christopher,Gros, Philippe C.
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p. 4978 - 4980
(2008/02/07)
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- Synthesis of 5-bromopyridyl-2-magnesium chloride and its application in the synthesis of functionalized pyridines
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(Chemical Equation Presented) The 5-bromopyridyl-2-magnesium chloride (2), which was not accessible previously, was efficiently synthesized for the first time via an iodomagnesium exchange reaction with 5-bromo-2-iodopyridine (1). This reactive intermediate was allowed to react with a variety of electrophiles to afford a range of useful functionalized pyridine derivatives. Application of this methodology to 5-bromo-2-iodo-3-picoline provided a simple and economical synthesis of a key intermediate for the preparation of Lonafarnib, a potent anticancer agent.
- Song, Jinhua J.,Yee, Nathan K.,Tan, Zhulin,Xu, Jinghua,Kapadia, Suresh R.,Senanayake, Chris H.
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p. 4905 - 4907
(2007/10/03)
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- Acetonitrile Derivatives as Carbonyl Synthons. One-Pot Preparation of Diheteroaryl Ketones via a Strategy of Sequential SNAr Substitution and Oxidation
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The anion of 2-aryl acetonitrile derivatives reacted with a variety of heteroaryl chlorides or bromides in an SNAr manifold to afford intermediate anions which were susceptible to oxidation. The addition of sodium peroxide and aqueous NH4OAc solution effected oxidation to afford aryl heteroaryl ketones in good yields. Aryl acetonitrile derivatives are thus umpolung-type synthons of the corresponding aryl carbonyl functionality.
- Yin, Zhiwei,Zhang, Zhongxing,Kadow, John F.,Meanwell, Nicholas A.,Wang, Tao
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p. 1364 - 1367
(2007/10/03)
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- Palladium-catalyzed carbonylative coupling of pyridine halides with aryl boronic acids
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The carbonylative Suzuki cross-coupling of a variety of mono-iodopyridines and bromopyridines (1a,b, 3a-c, 5) catalyzed by palladium-phosphane systems has been studied to prepare benzoylpyridine derivatives (2, 4, 6). The selectivity and the rate of the reaction are highly dependent on the reaction conditions, i.e. nature of the palladium catalyst precursor, solvent, temperature and CO pressure. The main side-products arise from direct, non-carbonylative cross-coupling. Under optimized conditions, benzoylpyridines are recovered in high yields (80-95%). The order of reactivity decreases from iodo- to bromopyridines and from 2-, 4- to 3-substituted halopyridines. The reactivity of dihalopyridines has been investigated; 2,6-dibromopyridine (7) and 3,5-dibromopyridine (11) are selectively transformed into either the corresponding benzoyl-phenylpyridine (8, 12) or the corresponding dibenzoylpyridine (9, 13). Dissymmetric 2,5-dihalopyridines (15a,b) are transformed into 2-benzoyl-5-bromopyridine (16) or 2,5-dibenzoylpyridine (17) in high yields.
- Couve-Bonnaire, Samuel,Carpentier, Jean-Fran?ois,Mortreux, André,Castanet, Yves
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p. 2793 - 2799
(2007/10/03)
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- Palladium-catalyzed carbonylative cross-coupling reactions of pyridine halides and aryl boronic acids: A convenient access to α-pyridyl ketones
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The proper choice of solvent, catalyst precursor and CO pressure enables the easy and selective transformation of mono- and dihalopyridines into phenyl pyridyl ketones in 81-95% yields.
- Couve-Bonnaire, Samuel,Carpentier, Jean-Fran?ois,Mortreux, André,Castanet, Yves
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p. 3689 - 3691
(2007/10/03)
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