- Towards an understanding of structure-property relationships in holetransport materials: The influence of molecular conformation on oxidation potential in poly(arvl)amines
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The influence of molecular conformation on the oxidation (ionisation) potential and electronic structure associated with several TPD-style hole transport materials has been assessed through a combination of single crystal X-ray diffraction, electrochemical and spectroelectrochemical methods and DFT calculations. The introduction of methyl groups can be used to tune the ionisation potential of these molecular species through a combination of electronic (inductive) and thermodynamic effects, while the conformation of the biphenyl portion of the molecular framework is found to play the greatest role in determining the Marcus-type reorganisation energy associated with the charge transport process on the molecular level. The Royal Society of Chemistry 2005.
- Low, Paul J.,Paterson, Michael A. J.,Yufit, Dmitry S.,Howard, Judith A. K.,Cherryman, Julian C.,Tackley, Daniel R.,Brook, Robert,Brown, Bev
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- Electronic Couplings in Organic Mixed-Valence Compounds: The Contribution of Photoelectron Spectroscopy
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We show that the electronic coupling in strongly coupled organic mixed-valence systems can be effectively probed by means of gas-phase ultraviolet photoelectron spectroscopy (UPS). Taking six diamines as examples, the UPS estimates for the electronic coup
- Coropceanu, Veaceslav,Gruhn, Nadine E.,Barlow, Stephen,Lambert, Christoph,Durivage, Jason C.,Bill, Tonja G.,Noell, Gilbert,Marder, Seth R.,Bredas, Jean-Luc
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Read Online
- Pulse-electrolysis stopped-flow method for the electrospectroscopic analysis of short-lived intermediates generated in the electrooxidation of triphenylamine
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A new analytical method was developed for the electrochemical and spectroscopic analyses of short-lived intermediates generated during electrochemical processes. Manyfaceted conclusions can be drawn from spectroscopic measurements after pulse electrolysis with a column electrode; e.g. dynamic transformation profiles of absorption spectra correspond to the applied potential. The fundamental characteristics of this method are described in detail. Electrolytic efficiency in the carbon-wool column electrode was evaluated in controlled-potential and controlled-current pulse electrolysis of the tetracyanoquinodimethane anion radical (TCNQ*-). In the controlled-potential operation, 0.11 mM TCNQ*-, was electrolyzed quantitatively within 200 ms. Up to 2.2 mM, the controlled-current operation permitted quantitative electrolysis with a 50-ms current pulse. Kinetic analysis of the dimerization reaction of the triphenylamine (TPA) cation radical (TPA*+) was carried out by this method. The pure solution containing only TPA*+ was successfully prepared by pulse electrolysis without any Interference by the consecutive reactions. Therefore the absorption coefficient of TPA*+ was easily determined and the dimerization rate constant of TPA*+ was quite simply analyzed by following the absorbance decay of TPA*+. The effect of the parent molecules on the reaction was also clarified by mixing TPA and TPA*+ solutions.
- Oyama, Munetaka,Nozaki, Koichi,Okazaki, Satoshi
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Read Online
- Persistent perfluoroalkyl radical investigations under reductive environment: Reaction with electron-donating reagents
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The reactivity of persistent perfluoroalkyl radical, perfluoro-3-ethyl-2,4-dimethyl-3-pentyl (1), with various electron-donating reagents was investigated. It is revealed that 1 which is robust under oxidative conditions is rather vulnerable under reductive conditions. Thus, Lewis bases such as triethylamine and triphenylpnictogens (Ph3Pn, Pn=N, P, As, Sb, Bi) and some soft anions such as iodide or tetraphenyl borate reacted with 1 to give perfluoro-3-isopropyl-4-methylpent-2-ene (2) quantitatively. Even very weak Lewis bases such as diethyl ether and diethylsulfide also reacted with 1 to give 2 and additionally a hydrido product, perfluoro-3-ethyl-3-H-2,4-dimethylpentane (4). Hydrogen gas did not react with 1 at all without a catalyst, but in the presence of metal Pd adsorbed on charcoal, smoothly reacted to give 2 in quantitative yield. Metal hydrides such as LiAlH4, NaBH4, NaH, BH3 (THF complex), Bu3SnH, Me2PhSiH reacted with 1 to give 2 and 4. That an electron transfer mechanism is operating in the formation of 2 is obvious, but not conclusive in the formation of 4.
- Ono, Taizo,Fukaya, Haruhiko,Hayashi, Eiji,Saida, Hiroko,Abe, Takashi,Henderson, Philip B.,E. Fernandez, Richard,Scherer, Kirby V.
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- Oligomerization of aromatic tertiary amines
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The oligomerization of some tertiary aromatic amines was studied using ferric chloride in a variety of solvent. The predominant dimer formation of triphenylamine (TPA) was observed in chloroform at O °C where concentration of TPA was 0.125 mmol/l and the molar ratio of ferric chloride to TPA was 4. Except for N-methyldiphenylamine, high molecular weight oligomers were formed in a variety of solvents.
- Sato, Hisaya,Kanegae, Aiko,Yamaguchi, Ryoji,Ogino, Kenji,Kurjata, Jan
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Read Online
- A fast-response electrochromic device based on a composite gel film comprising triphenylamine derivatives and WO3
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To obtain an electrochromic device with a quick response and multicolor change,N,N′-(4-((3-(triethoxysilyl)propyl)imino)methyl)phenyl-N,N′-diphenyl-4,4′-biphenyl-diamine (TPB-PSSO) containing a tetraphenylbenzidine (TPB) unit and siloxane group was synthesized, and its electrochromic properties were investigated. Using the TPB-PSSO gel film and a WO3/TPB-PSSO gel film as active materials, electrochromic devices (ECDs) having the structures indium tin oxide (ITO)/TPB-PSSO gel film/ITO and ITO/WO3film/TPB-PSSO gel film/ITO, respectively, were prepared. These two devices exhibited a fast response according to chronoamperometry measurements, with coloring and bleaching times of 4 and 9 ms and 5 and 5 ms, respectively.
- Zhang, Xuejian,Zeng, Jinming,Xu, Zipeng,Zhu, Mimi,Liu, Ping
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p. 5503 - 5508
(2021/04/06)
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- Catalytic and Aerobic Oxidative Biaryl Coupling of Anilines Using a Recyclable Heterogeneous Catalyst for Synthesis of Benzidines and Bicarbazoles
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In this study, a heterogeneous rhodium-catalyzed oxidative homocoupling reaction of anilines utilizing molecular oxygen as the sole oxidant is reported. Employing a commercially available and recyclable Rh/C catalyst enabled the oxidative dimerization of various anilines, including N,N-disubstituted and N-monosubstituted anilines, as well as diarylamines, triarylamines, and carbazoles. Additionally, the catalytic protocol was extended to the ortho-ortho coupling of anilines, affording 2,2′-diaminobiphenyls with high regioselectivity. Notably, the developed approach provides rapid access to diversely functionalized benzidines and diaminobiphenyls in an operationally simple, practical, and environmentally friendly manner.
- Matsumoto, Kenji,Toubaru, Yasunori,Tachikawa, Shohei,Miki, Ayaka,Sakai, Kentaro,Koroki, Syota,Hirokane, Tsukasa,Shindo, Mitsuru,Yoshida, Masahiro
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supporting information
p. 15154 - 15166
(2020/12/23)
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- Redox-Active Guanidines in Proton-Coupled Electron-Transfer Reactions: Real Alternatives to Benzoquinones?
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Guanidino-functionalized aromatics (GFAs) are readily available, stable organic redox-active compounds. In this work we apply one particular GFA compound, 1,2,4,5-tetrakis(tetramethylguanidino)benzene, in its oxidized form in a variety of oxidation/oxidative coupling reactions to demonstrate the scope of its proton-coupled electron transfer (PCET) reactivity. Addition of an excess of acid boosts its oxidation power, enabling the oxidative coupling of substrates with redox potentials of at least +0.77 V vs. Fc+/Fc. The green recyclability by catalytic re-oxidation with dioxygen is also shown. Finally, a direct comparison indicates that GFAs are real alternatives to toxic halo- or cyano-substituted benzoquinones.
- Wild, Ute,Hübner, Olaf,Himmel, Hans-J?rg
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supporting information
p. 15988 - 15992
(2019/11/13)
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- MANUFACTURING METHOD OF AROMATIC AMINE COMPOUND, NOVEL AROMATIC AMINE COMPOUND, FLUORESCENT EMISSION MATERIAL AND ULTRAVIOLET ABSORBER
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PROBLEM TO BE SOLVED: To provide a manufacturing method of an aromatic amine compound by a Buchwald-Hartwig reaction using a novel palladium catalyst, especially a manufacturing method of the aromatic amine compound capable of providing an object compound at high efficiency even with a substrate which does not proceed a reaction favorably in prior art, further a manufacturing method of the aromatic amine compound capable of providing a novel aromatic amine compound having no synthetic example previously, a novel fluorescent emission material and an ultraviolet absorber consisting of a novel aromatic amine compounds, a 5-aminothiazole compound. SOLUTION: The manufacturing method of an aromatic amine compound includes reacting an aromatic halogen compound and an amine compound in the presence of palladium nanoparticles and a base with a phosphine compound as a protectant to obtain the aromatic amine compound. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0106; 0108; 0109; 0110
(2018/09/26)
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- Electron-Catalyzed Coupling of Magnesium Amides with Aryl Iodides
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An electron was found to catalyze the coupling of magnesium diarylamides with aryl iodides giving triarylamines through a radical-anion intermediate. The transformation requires no transition metal catalysts or additives, and a wide array of products are formed in good-to-excellent yields.
- Kiriyama, Kazuya,Okura, Keisho,Tamakuni, Fumiko,Shirakawa, Eiji
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supporting information
p. 4519 - 4522
(2018/03/13)
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- Metal-Free Oxidative C-C Coupling of Arylamines Using a Quinone-Based Organic Oxidant
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A variety of arylamines are shown to undergo oxidative C-C bond formation using quinone-based chloranil/H+ reagent as the recyclable organic (metal-free) oxidant system to afford benzidines/naphthidines. Arylamines (3°/2°) designed with various substituents were employed to understand the steric as well as electronic preferences of oxidative dimerization, and a mechanism involving amine radical cation has been proposed. The tetraphenylbenzidine derivative obtained via oxidative C-C coupling has been further converted to blue-emissive hole-transporting material via a simple chemical transformation. This study highlights the preparation of novel HTMs in a simple, economic, and efficient manner.
- Maddala, Sudhakar,Mallick, Sudesh,Venkatakrishnan, Parthasarathy
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supporting information
p. 8958 - 8972
(2017/09/11)
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- PdCl2(Ph3P)2/Salicylaldimine Catalyzed Diarylation of Anilines with Unactivated Aryl Chlorides
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Triphenylphosphine and salicylaldimine could be used as a mixed ligand system to obtain a high catalytic activity for palladium catalyzed diarylation of primary anilines with unactivated aryl chlorides by the synergistic effect of ligands. The activity and selectivity of the catalytic system could be improved by modifying the structure of salicylaldimine. In refluxing o-xylene, PdCl2(Ph3P)2 with 2,5-ditrifluoromethyl N-phenylsalicylaldimine as a coligand shows high efficiency for the diarylation of various anilines. The catalytic system shows good toleration for the steric hindrance of the substrates. The facile catalytic system works as well on the multiple arylation of 1,1′-biphenyl- 4,4′-diamine with aryl chlorides to afford N,N,N′,N′-tetraaryl-1,1′-biphenyl-4,4′-diamines which are important intermediates of organic light emitting diode (OLED) hole transport materials.
- Tao, Xiaochun,Li, Lei,Zhou, Yu,Qian, Xuanying,Zhao, Min,Cai, Liangzhen,Xie, Xiaomin
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p. 1749 - 1754
(2017/10/06)
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- Synthesis and investigation of triphenylamine-based double branched organic dyes for p-type dye-sensitized solar cells
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Two double branched organic dyes (T1I and T2I) were synthesized, characterized, and employed as photosensitizers in p-type dye-sensitized solar cells (p-DSSC); we have compared with corresponding single branched dye (TC1) and reference dye P1. The absorbance of the dyes in solution was red shifted and the oxidation potential gradually decreased with increasing the donating ability. It was found that modification from single branched (TC1) to double branched (T1I and T2I) system resulted in increased photocurrent density leading to the higher photovoltaic performances. The charge transporting ability is increased with the introduction of double branching, as evidenced from electrochemical impedance analysis.
- Bao, Le Quoc,Phuong, Ho,Thuy, Chau Thi Thanh,Lee, Ji Won,Kim, Jae Hong,Thogiti, Suresh
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p. 109 - 117
(2017/11/14)
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- Oxidative Dimerization of Triarylamines Promoted by WCl6, Including the Solid State Isolation and the Crystallographic Characterization of a Triphenylammonium Salt
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The triphenylammonium salt [NHPh3][WCl6], 1, and the product of the C-C dimerization of triphenylamine, Ph2N(C6H4)2NPh2, 2, were afforded from the reaction between WCl6 and NPh3 in CH2Cl2. Compound 2 was isolated in 43% yield upon hydrolysis of the reaction mixture. The X-ray structure of 1 provides the first crystallographic characterization of the triphenylammonium ion. Combined EPR and DFT studies gave insight into the reaction mechanism, and allowed the identification of WCl5···[Cl(C6H4)NPh2] as a presumable key intermediate. The reactions of WCl6 with 4-bromotriphenylamine, 4,4′-dimethyltriphenylamine, 9-phenylcarbazole, followed by hydrolytic treatment, led to the dimerization products 3-6, in admixture with variable amounts of the parent amines. N,N,N′,N′-tetrakis(4-bromophenyl)-[1,1′-biphenyl]-4,4′-diamine, 3, was isolated in 60% yield from the reaction of WCl6 with 4,4′-dibromotriphenylamine.
- Bortoluzzi, Marco,Marchetti, Fabio,Pampaloni, Guido,Pinzino, Calogero,Zacchini, Stefano
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p. 887 - 893
(2016/02/03)
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- Production of the triarylamine
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PROBLEM TO BE SOLVED: To provide a method for producing a triarylamine compound by coupling an N, N-dialkyl sulfamate compound and a diaryl amide compound in the presence of a nickel catalyst.SOLUTION: A triarylamine is produced by allowing an N, N-dialkyl sulfamate represented by formula (1) (in the formula, Arrepresents a phenyl group or the like, and Rand Reach independently represents a 1-4C alkyl group that may be substituted with a fluorine atom) to react with a diarylamide in the presence of a nickel catalyst.
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Paragraph 0051-0052
(2017/01/31)
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- Identification of Fleeting Electrochemical Reaction Intermediates Using Desorption Electrospray Ionization Mass Spectrometry
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We report a new method for the mass spectrometric detection of fleeting reaction intermediates in electrochemical reactions utilizing a "waterwheel" working electrode setup. This setup takes inspiration from desorption electrospray ionization (DESI) mass spectrometry, where the sampling time is on the order of milliseconds, to sample directly from the surface of a working electrode for mass spectrometric analysis. We present data that show the formation of a diimine intermediate of the electrochemical oxidation of uric acid that has a lifetime in solution of 23 ms as well as data that provide evidence for the formation of a similar diimine species from the electrooxidation of xanthine, which has not been previously observed.
- Brown, Timothy A.,Chen, Hao,Zare, Richard N.
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p. 7274 - 7277
(2015/06/30)
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- Effects of solvent and base on the palladium-catalyzed amination: PdCl 2(Ph3P)2/Ph3P-catalyzed selective arylation of primary anilines with aryl bromides
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A readily accessible catalytic system, PdCl2(Ph 3P)2/Ph3P, was developed for the selective arylation of primary anilines with aryl bromides. The strong influence of solvents and bases on the catalytic activity was observed. In refluxing o-xylene, triphenylphosphine shows high efficiency for Pd-catalyzed intermolecular amination reactions. By changing the bases, mono- and diarylation of primary amines could be selectively achieved in high yields. Moreover, the catalytic system showed good toleration for the steric hindrance of anilines. A series of N,N,N′,N′-tetraaryl-1,1′-biphenyl-4,4′- diamines, important intermediates of OLED hole transport materials, were synthesized facilely via coupling reactions between 4,4′-diaminobiphenyls and aryl bromides.
- Cai, Liangzhen,Qian, Xuanying,Song, Wenjing,Liu, Taoping,Tao, Xiaochun,Li, Wanfang,Xie, Xiaomin
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p. 4754 - 4759
(2014/06/24)
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- Palladium-catalyzed ligand-free and aqueous Suzuki reaction for the construction of (hetero)aryl-substituted triphenylamine derivatives
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This paper reports an efficient synthesis of triphenylamine (TPA) derivatives via a palladium-catalyzed Suzuki reaction of (hetero)aryl halides with 4-(diphenylamino)phenylboronic acid (DPBA) in aqueous ethanol under aerobic and ligand-free conditions. Heteroaryl halides, namely pyridyl bromides, quinolyl bromides, pyrimidinyl bromides, 2-chloropyrazine and sulfur-containing heteroaryl bromides, could react smoothly with DPBA, affording good to excellent yields under mild conditions. In addition, aryl bromides were also successfully employed in the cross-couplings with DPBA and furnished the products in high yields at room temperature. The cross-coupling of 4-bromobenzonitrile with DPBA gave the desired product in a quantitative yield within 2 min, resulting in a TOF up to 5820 h-1.
- Liu, Chun,Rao, Xiaofeng,Song, Xinlong,Qiu, Jieshan,Jin, Zilin
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p. 526 - 531
(2013/04/10)
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- Ni-catalyzed arylation of bromomagnesium diarylamides with aryl N,N-dimethylsulfamates
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The combination use of Ni(cod)2 and N,N-1,3-bis(2,6- diisopropylphenyl)-4-imidazoline-2-ylidene as a catalyst successfully gave unsymmetrical N,N-diaryl-N′,N′-diphenyl-1,1′-biphenyl-4, 4′-diamines through the arylation of bromomagnesium diarylamide with 1-(4′-diphenylamino-1,1′-biphenylyl) N,N-dimethylsulfamate. This Ni catalyst and Grignard reagents of diaryl or monoarylamides were also useful in the syntheses of various triarylamines and diarylamines from corresponding aryl N,N-dimethylsulfamates. 2012 Elsevier Ltd. All rights reserved.
- Tadaoka, Hiroshi,Yamakawa, Tetsu
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p. 5531 - 5534
(2012/11/13)
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- Efficient solid emitters with aggregation-induced emission and intramolecular charge transfer characteristics: Molecular design, synthesis, photophysical behaviors, and OLED application
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Emissive electron donor-acceptor (D-A) conjugates have a wide variety of applications in biophotonics, two-photon absorption materials, organic lasers, long wavelength emitters, and so forth. However, it is still a challenge to synthesize high solid-state efficiency D-A structured emitters due to the notorious aggregation-caused quenching (ACQ) effect. Though some D-A systems are reported to show aggregation-induced emission (AIE) behaviors, most are only selectively AIE-active in highly polar solvents, showing decreased solid-sate emission efficiencies compared to those in nonpolar solvents. Here we report the triphenylamine (TPA) and 2,3,3-triphenylacrylonitrile (TPAN) based D-A architectures, namely, TPA3TPAN and DTPA4TPAN. Decoration of arylamines with TPAN changes their emission behaviors from ACQ to AIE, making resulting TPA3TPAN and DTPA4TPAN nonluminescent in common solvents but highly emissive when aggregated as nanoparticles, solid powders, and thin films owing to their highly twisted configurations. Both compounds also display a bathochromic effect due to their intramolecular charge transfer (ICT) attribute. Combined ICT and AIE features render TPA3TPAN and DTPA4TPAN intense solid yellow emitters with quantum efficiencies of 33.2% and 38.2%, respectively. They are also thermally and morphologically stable, with decomposition and glass transition temperatures (Td/Tg) being 365/127 and 377/141 °C, respectively. Multilayer electroluminescence (EL) devices are constructed, which emit yellow EL with maximum luminance, current, power, and external quantum efficiencies up to 3101 cd/m2, 6.16 cd/A, 2.64 lm/W, and 2.18%, respectively. These results indicate that it is promising to fabricate high efficiency AIE-ICT luminogens with tunable emissions through rational combination and modulation of propeller-like donors and/or acceptors, thus paving the way for their biophotonic and optoelectronic applications.
- Yuan, Wang Zhang,Gong, Yongyang,Chen, Shuming,Shen, Xiao Yuan,Lam, Jacky W. Y.,Lu, Ping,Lu, Yawei,Wang, Zhiming,Hu, Rongrong,Xie, Ni,Kwok, Hoi Sing,Zhang, Yongming,Sun, Jing Zhi,Tang, Ben Zhong
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scheme or table
p. 1518 - 1528
(2012/08/08)
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- Very fast, ligand-free and aerobic protocol for the synthesis of 4-aryl-substituted triphenylamine derivatives
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A fast, convenient and ligand-free protocol for the synthesis of a series of 4-aryl-substituted triphenylamine derivatives by a palladium-catalysed aerobic Suzuki reaction of aryl halides with [4-(diphenylamino)phenyl]boronic acid in aqueousiPrOH is described. Importantly, both aryl bromides and heteroaryl halides afforded good to excellent yields under mild conditions. A facile, efficient and general ligand-free Suzuki reaction in aqueous iPrOH is described. Under the optimized conditions, both aryl bromides and heteroaryl halidesreacted rapidly with [4-(diphenylamino)phenyl]boronic acid, providing a series of 4-aryl-substituted triphenylamine derivatives in good to excellent yields.
- Liu, Chun,Ni, Qijian,Qiu, Jieshan
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experimental part
p. 3009 - 3015
(2011/06/28)
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- Clean synthesis of triarylamines: Buchwald-Hartwig reaction in water with amphiphilic resin-supported palladium complexes
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Catalytic aromatic amination was achieved in water under heterogeneous conditions by the use of palladium complexes anchored to the amphiphilic PS-PEG resin with little palladium leaching to provide a green and clean (metal-uncontaminated) protocol for the preparation of triarylamines, including the optoelectronically active N,N,N′,N′-tetraaryl-1,1′- biphenyl-4,4′-diamines (TPDs).
- Hirai, Yoshinori,Uozumi, Yasuhiro
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supporting information; experimental part
p. 1103 - 1105
(2010/06/18)
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- Heterogeneous aromatic amination of aryl halides with arylamines in water with PS-PEG resin-supported palladium complexes
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Catalytic aromatic amination is achieved in water under heterogeneous conditions by the use of immobilized palladium complexes coordinated with the amphiphilic polystyrene-poly-(ethylene glycol) resin-supported di(tert-butyl)phosphine ligand. Aromatic amination of aryl halides with diphenylamine and N,N-double arylation of anilines with bromobenzene were found to proceed in water with broad substrate tolerance to give the triarylamines in high yield with high recyclability of the polymeric catalyst beads. Very little palladium leached from the polymeric catalyst under the waterbased reaction conditions to provide a green and clean (metal-uncontaminated) protocol for the preparation of triarylamines, including the optoelectronically active N,N,N',N'-tetraaryl-1,1'-biphenyl-4,4'-diamines (TPDs).
- Hirai, Yoshinori,Uozumi, Yasuhiro
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supporting information; experimental part
p. 1788 - 1795
(2011/04/16)
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- Changing the behavior of chromophores from aggregation-caused quenching to aggregation-induced emission: Development of highly efficient light emitters in the solid state
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(Figure Presented) Efficient solid-state emitters developed by a new approach are described. While emission from triphenylamine (TPA) and its dimer (DTPA) is weakened by aggregation, attaching tetraphenylethene (TPE) units to the amines boosts their emission efficiencies up to 100% in the aggregate state. without harming their hole-transport properties. The resultant 3TPETPA and 4TPEDTPA luminogens show excellent electroluminescence performance.
- Yuan, Wang Zhang,Lu, Ping,Chen, Shuming,Lam, Jacky W. Y.,Wang, Zhiming,Liu, Yang,Kwok, Hoi Sing,Yuguang, Ma.,Tang, Ben Zhong
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scheme or table
p. 2159 - 2163
(2011/11/11)
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- Evaluation of aromatic amination catalyzed by palladium on carbon: A practical synthesis of triarylamines
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A heterogeneous palladium on carbon (Pd/C)-catalyzed coupling between amines and aromatic halides including aromatic chlorides has been achieved using sodium tert-butoxide (NaO-t-Bu) and 1,1′-bis(diphenylphosphino)ferrocene (dppf) as a ligand in cyclopentyl methyl ether (CPME). The use of potassium tert-butoxide (KO-t-Bu) in place of NaO-t-Bu brought about the benzyne-mediated aromatic amination even without Pd/C and dppf, giving a mixture of regioisomers when 4-substituted bromobenzenes were employed as the substrate. The combination of Pd/C, dppf, NaO-t-Bu could be utilized for the syntheses of a broad range of triarylamines by replacing CPME with mesitylene which can provide a higher reaction temperature. The Pd/C could be quantitatively recovered and reused until at least the fourth cycle without any loss in catalytic activity. The quite low leaching of palladium (1.1%) was demonstrated by an inductively coupled plasma-atomic emission spectrometric analysis.
- Monguchi, Yasunari,Kitamoto, Katsunori,Ikawa, Takashi,Maegawa, Tomohiro,Sajiki, Hironao
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supporting information; experimental part
p. 2767 - 2777
(2009/12/08)
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- Cu(II)-mediated generation of triarylamine radical cations and their dimerization. An easy route to tetraarylbenzidines
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(Chemical Equation Presented) Triphenylamine (TPA) derivatives react with Cu2+ in acetonitrile to give TPA radical cations which undergo dimerization and deprotonation reactions to yield tetraphenylbenzidines (TPB). Synthetic utility of this reaction is demonstrated using several triphenylamine derivatives, and yields in excess of 80% are obtained in most cases. Involvement of the amine radical cations in these reactions was confirmed by ESR and absorption spectroscopic studies. A mechanism consistent with all observations is proposed. This study also revealed a very good correlation between the free energy change for radical cation formation and product yields.
- Sreenath, Kesavapillai,Suneesh, Chettiyam Veettil,Ratheesh Kumar, Venugopal K.,Gopidas, Karical R.
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p. 3245 - 3251
(2008/09/20)
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- Ullmann reaction in tetraethyl orthosilicate: A novel synthesis of triarylamines and diaryl ethers
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A novel synthesis of triarylamines and diaryl ethers is reported; a feature of this process is the ligand-free copper-catalysed C-N and C-O bond formation in tetraethyl orthosilicate. The Royal Society of Chemistry.
- Zhao, Yuanhong,Wang, Yunsong,Sun, Hongwei,Li, Liang,Zhang, Hongbin
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p. 3186 - 3188
(2008/02/13)
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- Facile synthesis of 9-azajulolidine and its application to post-Ullmann reactions
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This Letter describes the efficient synthesis of 9-azajulolidine from readily available reagents and its utilization as an effective electron-rich ligand for post-Ullmann-type reactions, that is, for C(aryl)-heteroatom (N, O, S) bond formation reactions, with dramatically enhanced reaction rates.
- Wong, Ken-Tsung,Ku, Sung-Yu,Yen, Feng-Wen
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p. 5051 - 5054
(2008/02/12)
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- N-Arylation of aliphatic, aromatic and heteroaromatic amines catalyzed by copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate)
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Copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) was found to be an efficient catalyst for N-arylation of aliphatic, aromatic and heteroaromatic amines with aryl iodides/bromides under mild conditions. The system tolerated a variety of hindered and functionalized amines/aryl halides and the desired N-aryl amines were obtained in good to excellent yields.
- Nandurkar, Nitin S.,Bhanushali, Mayur J.,Bhor, Malhari D.,Bhanage, Bhalchandra M.
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p. 6573 - 6576
(2008/02/12)
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- Diazabutadiene: a simple and efficient ligand for copper-catalyzed N-arylation of aromatic amines
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Diazabutadienes (DABs) were chosen as ancillary ligands in the Cu-catalyzed C-N coupling reaction for the synthesis of triarylamines. A combination of CuI/DAB (1) [1: N,N′-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene] was found to be an efficient catalyst system for N-arylation of diarylamines and anilines with aryl iodides, affording the desired products in good to excellent yields.
- Liu, Yu-Hua,Chen, Chen,Yang, Lian-Ming
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p. 9275 - 9278
(2007/10/03)
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- Method for preparing three types of benzidine compounds in a specific ratio
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A method for preparing three types of benzidine compounds in a specific ratio, the method uses two types of diphenylamine compounds and one type of biphenyldihalide compound in a specific ratio as reactants to mix with an organic solvent and an additive to synthesize benzidine compounds in one step. The synthesized three types of benzidine compounds specially perform in a designated mixturing ratio having excellent photoelectric characteristics for a charge transporting layer in an organic photo-conductive drum.
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Page/Page column 2
(2008/06/13)
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- Palladium catalysed aryl amination reactions in supercritical carbon dioxide
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Palladium catalysed C-N bond formation in supercritical carbon dioxide has been accomplished. Carbamic acid formation is avoided in part through the use of an N-silylamine as the coupling partner. Employing a catalyst system of Pd 2dba3 (1 mol%) and 2-dicyclohexylphosphino-2′, 4′,6′-triisopropyl-1,1′-biphenyl (X-Phos) (2 mol%) enabled the catalytic amination of aryl bromides and chlorides with N-silylanilines to be realised in excellent yield. Extension of the methodology to the N-arylation of N-silyldiarylamines, N-silylazoles and N-silylsulfonamides is reported. The Royal Society of Chemistry 2005.
- Smith, Catherine J.,Tsang, Melanie W.S.,Holmes, Andrew B.,Danheiser, Rick L.,Tester, Jefferson W.
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p. 3767 - 3781
(2007/10/03)
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- Arylation of diarylamines catalyzed by Ni(II)-PPh3 system
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(Chemical Equation Presented) The cross-coupling of bromomagnesium diarylamides, generated in situ from diarylamines, with aryl bromides or iodides can be effected with a simple NiCl2(PPh3) 2-PPh3 catalyst system under relatively mild conditions. This coupling reaction is an inexpensive, convenient, and practical method, functioning as an alternative to the corresponding Pd-catalyzed or Cu-mediated process for the synthesis of triarylamines.
- Chen, Chen,Yang, Lian-Ming
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p. 2209 - 2211
(2007/10/03)
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- Electrophotographic member
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Disclosed is an electrophotographic member containing as a charge transport material a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative which is remarkably excellent in solubility in an organic solvent and/or a binder such as polycarbonate resin, etc., can show very excellent electrophotographic properties such as high sensitivity, low residual potential and high durability. Further, a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative usable as a charge transport material, and a process for producing the same are disclosed. Furthermore, a fluorine-containing diarylamine usable for producing the fluorine-containing N,N,N',N'-tetraarylbenzidine derivative, and a process for producing the same are disclosed.
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- Condensations of 1,4-Cyclohexanediones and Secondary Aromatic Amines. II. N-Phenylation of Diarylamines
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The condensations of 1,4-cyclohexanedione with several diphenylamines were investigated in order to determine the limit of the utility of this reaction for the N-phenylation of aromatic secondary amines. 4-Methoxy-, 4,4'-dimethyl-, and 4,4'-dibromodiphenylamines produced their N-phenylated compounds in fairly good yields, but 4-hydroxy-, 3-methoxy-, and 4,4'-bis(dimethylamino)diphenylamines produced poor yields.Nitro-substituted diphenylamines gave N-phenyl derivatives in low yields along with N-4-hydroxyphenyl derivatives.N,N'-Diphenyl-p-phenylenediamine and N,N'-diphenylbenzidine gave correspondig tetra-N-phenyl diamines in good yields.The condensation of N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, di-2-pyridylamine, phenothiazine, and carbazole with 1,4-cyclohexanedione were also examined.
- Haga, Kazuo,Iwaya, Katsumasa,Kaneko, Ryohei
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p. 803 - 808
(2007/10/02)
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- Redox Kinetics of Metal Complexes in Non-aqueous Solutions. Part 13. The Ferriin Oxidation of Aprotic Donors in Acetonitrile: Relationships between Donor and Reducing Capabilities
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The reactions of a variety of neutral donors (D) with ferriin in acetonitrile have been examined.The course of reaction and the products formed vary depending on the base strength and the structure of the donor, the two competing mechanisms discerned being (a) oxidation of D and (b) deprotonation of the residual water or the MeCN solutions initiating the reaction of hydroxide ions with ferriin.For the stability of ferriin solutions, there is a decrease in the order MeNO2 > MeCN > dmf > py > hmpa > Et3N which is the order of increasing donor numbers (DN).The very strong donors hmpa and Et3N (and all other aliphatic amines as well) are readily oxidized via charge transfer in an initially formed 1:1 complex Fe(phen)3D(3+) whose nature is discussed.In the case of Et3N, this complex dissociates spontaneously into ferroin and Et3N(+), the latter giving diethylvinylamine which polymerizes with release of diethylamine.For hmpa, charge transfer in Fe(phen)3(hmpa)(3+) needs base catalysis of a second hmpa molecule.The radical thus formed deprives hydrogen from acetonitrile forming succinonitrile.In contrast, Et3PO though being similar in basicity, is not oxidized.This comparison emphasizes the peculiar role of alkyl groups linked to nitrogen for the oxidation chemistry of organic substrates.Donors of donor numbers below that of hmpa are not oxidized noticeably but give rise to mechanism (b).The hydroxide formed displaces partly phen, a greenish precipitate separating identified as a novel high-molecular weight congener of tetrakis(phen)diaquo-μ-oxo-di-iron(III).The following stability order of radicals , derived from the donors, is suggested, dmf > hmpa > MeCN > R3N > dmso.Further, the ferriin oxidation of triphenylamine has been examined.
- Schmid, Roland,Soukup, Rudolf W.,Sapunov, Valentin N.
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p. 1045 - 1075
(2007/10/02)
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- Oxidation von Triphenylamin in Acetonitril an rotierenden Scheibenelektroden
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The standard potential for the oxidation of triphenylamine to the radical cation in acetonitrile containing 0.1 M lithium perchlorate is U0/= 601 mV vs. the silver electrode in 0.1 M silver nitrate, the standard rate constant ks= 3.1*10-2 cm s-1, and the transfer coefficient α=0.58.The radical cation dimerizes at a rate constant k2 =2.2(+/-0.2)*103M-1s-1 yielding the N,N,N',N',-tetraphenylbenzidinium dication.The dimerization is followed by a rapid deprotonization and a rapid homogeneous oxidation of the benzidine by the triphenylamine radical cationyielding the semiquinoneimine and the quinonediimine at the ratio 2:3.The rate constant for the synproportionation of the quinonediimine and the benzidine yielding the semiquinoneimine was determined at k2 =4.1*106M-1s-1.The semiquinoneimine reacts with 2,6-lutidine in a reaction with rate constant k2 =137 M-1s-1 and with other bases.The kinetic data result from electrochemical and spectrophotometric measurements at the rotating disc electrode with optically transparent ring and at the rotating ring-disc electrode.Spectra of the extinction coefficients were determined for stable and transient reaction products. - Keywords: Organic electrochemistry / Reaction kinetics / Rotating disc / Spectrophotochemistry
- Debrodt, H.,Heusler, K. E.
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