- Oxidative activation in aromatic substitutions. Reactions of N,N- dimethylanilines with secondary anilines promoted by thallium triacetate
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The reactions of N,N-dimethyl-p-anisidine (1a), N,N-dimethylaniline (1b), and N,N-dimethyl-p-fluoroaniline (1c) toward secondary anilines 2(a- d)-H in the presence of thallium triacetate sesquihydrate have been studied as representative of a novel oxidatively activated aromatic substitution affording 1,4-benzenediamine derivatives 3a-d. All of the substrates considered gave substitution with diphenylamine (2d-H). However, with anilines 2b,c-H, only 1a underwent substitution, and substrates 1b,c were practically unreactive. The observed differences in reactivity are well accounted for within a mechanistic framework wherein oxidative activation of both the substrate and the secondary aniline is regarded as alternatively (or simultaneously) possible, depending on the redox characteristics of the reactants. For instance, it can be stated, beyond any reasonable doubt, that reactions of 1a with 2b,c-H proceed via nucleophilic attack of the latter on 1a+., and that the reaction of 1a-c with 2d-H must involve the diphenylamino radical 2d·.
- Ciminale,Ciardo,Francioso,Nacci
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- Visible light sensitized near-infrared luminescence of ytterbium: Via ILCT states in quadruple-stranded helicates
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Visible light excitation is especially important for the NIR emitting materials that are employed in biochemistry and cell biology, since living tissues are generally damaged under UV light irradiation. Here, two new bis-β-diketones, L1 and L2 (L1 = 4,4′-di(4,4′,4′′-trifluoro-1,3-dioxobutyl)-triphenylamine; L2 = 4-(N,N-dimethylamino)-4′,4′′-di(4,4′,4′′-trifluoro-1,3-dioxobutyl)-triphenylamine), featuring intra-ligand charge transfer (ILCT) excited states, have been designed and prepared for the synthesis of a series of anionic quadruple-stranded dinuclear helicates (HNEt3)2[M2L14] and (HNEt3)2[M2L24], where M = Yb, Gd and Y. 1H NMR and electrospray mass spectrometry confirm the formation of single complex species in solution. According to the comprehensive spectral characterization and in combination with quantum chemical modelling, the ILCT feature of L1 and L2 is confirmed. The presence of ILCT allows the use of lower energy excitation wavelengths in the visible spectral region to sensitize ytterbium NIR luminescence. In (HNEt3)2[Yb2L24], the introduction of strong electron donating N,N-dimethyl leads to a remarkable red shift of the absorbance edge to 560 nm compared with that in (HNEt3)2[Yb2L14] at 450 nm. Upon excitation with blue light, the two ytterbium helicates show excellent NIR luminescence in the range of 900-1100 nm, with the luminescence quantum yields reaching 1.1% for (HNEt3)2[Yb2L14] and 1.5% for (HNEt3)2[Yb2L24] in CH3CN. Luminescence mechanism experiments show that the ILCT singlet path and classic triplet state path together participate in sensitizing Yb(iii) ion NIR luminescence.
- Zhang, Zihan,Zhou, Yanyan,Li, Hongfeng,Gao, Ting,Yan, Pengfei
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- Biaryl Phosphine Based Pd(II) Amido Complexes: The Effect of Ligand Structure on Reductive Elimination
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Kinetic studies conducted under both catalytic and stoichiometric conditions were employed to investigate the reductive elimination of RuPhos (2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl) based palladium amido complexes. These complexes were found to be the resting state in Pd-catalyzed cross-coupling reactions for a range of aryl halides and diarylamines. Hammett plots demonstrated that Pd(II) amido complexes derived from electron-deficient aryl halides or electron-rich diarylamines undergo faster rates of reductive elimination. A Hammett study employing SPhos (2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl) and analogues of SPhos demonstrated that electron donation of the lower aryl group is key to the stability of the amido complex with respect to reductive elimination. The rate of reductive elimination of an amido complex based on a BrettPhos-RuPhos hybrid ligand (2-(dicyclohexylphosphino)-3,6-dimethoxy-2′,6′-diisopropoxybiphenyl) demonstrated that the presence of the 3-methoxy substituent on the "upper" ring of the ligand slows the rate of reductive elimination. These studies indicate that reductive elimination occurs readily for more nucleophilic amines such as N-alkyl anilines, N,N-dialkyl amines, and primary aliphatic amines using this class of ligands.
- Arrechea, Pedro Luis,Buchwald, Stephen L.
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supporting information
p. 12486 - 12493
(2016/10/07)
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- Catalytic carbon-nitrogen bond-forming cross-coupling using N-trimethylsilylamines
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Carbon-nitrogen bond-forming cross-coupling reaction of haloarenes with N-trimethylsilyl (TMS)-substituted secondary and primary arylamines proceeded with the aid of a palladium catalyst and a fluoride activator. Various TMS-N(aryl)2, TMS-NH(aryl), and TMS-N(alkyl)2 reacted to give the corresponding coupled products in high yields. Multi-TMS-amine nucleophiles such as N,N-(TMS)2-aniline and N,N′-Ph2-N,N′-(TMS)2-p-phenylenediamine also participated in this C-N coupling to give multiply C-N coupled products in high yields. The novel C-N cross-coupling reaction was successfully applied to C-N bond-forming polymerization. Relative rates of the cross-coupling of p-bromotoluene with N-TMS-substituted primary and secondary amines showed that N-TMS-diphenylamine reacted faster than N-TMS-N-methylaniline or N-TMS-aniline, and N-TMS-morpholine was the least reactive, indicating that the low basicity of the nitrogen nucleophile is the key for the smooth coupling.
- Minami, Yasunori,Komiyama, Takeshi,Shimizu, Kenta,Hiyama, Tamejiro,Goto, Osamu,Ikehira, Hideyuki
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p. 1437 - 1446
(2015/11/16)
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- Method for producing hydroxytriarylamine (by machine translation)
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PROBLEM TO BE SOLVED: To economically provide arylamines such as triarylamine. SOLUTION: An arylamine compound represented by formula (1) and an aryl compound having a leaving group represented by formula (2): X-Ar2-X1, are subjected to an arylamination reaction in the presence of a basic group, an alkaline metal salt and/or an alkaline earth metal salt, and an iron catalyst to thereby obtain arylamines such as triarylamines. In formula (1), Ar and Ar1are identical or different, and denote a substituted or non-substituted aryl group, and may be ring-condensed; and a denotes 1 or 2. In formula (2), X and X1are identical or different, and denote at least one leaving group selected from the group consisting of H or Br, I, CMs (mesylate), OTf (triflate) and OTs (tosylate), provided that X and X1are not simultaneously H, and have at least one leaving group; and Ar2denotes a substituted or non-substituted aryl group. COPYRIGHT: (C)2012,JPO&INPIT
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Paragraph 0038
(2018/02/24)
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- Silicon-based CN cross-coupling reaction
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Palladium-catalyzed CN bond-forming cross-coupling reaction of N-trimethylsilylamines with aryl bromides and chlorides is found to proceed in the presence of a fluoride activator in 1,3-dimethyl-2-imidazolidinone (DMI), giving triarylamines in excellent yields. When aryl bromide and bis(silyl)amine were used in this reaction, double CN bondforming products were obtained in high yields. The present reaction was successfully applied to CN bond-forming polymerization.
- Shimizu, Kenta,Minami, Yasunori,Goto, Osamu,Ikehira, Hideyuki,Hiyama, Tamejiro
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supporting information
p. 438 - 440
(2014/04/17)
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- Iron-catalyzed aromatic amination for nonsymmetrical triarylamine synthesis
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Novel iron-catalyzed amination reactions of various aryl bromides have been developed for the synthesis of diaryl- and triarylamines. The key to the success of this protocol is the use of in situ generated magnesium amides in the presence of a lithium halide, which dramatically increases the product yield. The present method is simple and free of precious and expensive metals and ligands, thus providing a facile route to triarylamines, a recurrent core unit in organic electronic materials as well as pharmaceuticals.
- Hatakeyama, Takuji,Imayoshi, Ryuji,Yoshimoto, Yuya,Ghorai, Sujit K.,Jin, Masayoshi,Takaya, Hikaru,Norisuye, Kazuhiro,Sohrin, Yoshiki,Nakamura, Masaharu
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supporting information
p. 20262 - 20265
(2013/02/23)
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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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- Diphenylnitrenium ion: Cyclization, electron transfer, and polymerization reactions
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Reactions of diphenylnitrenium ion were examined using laser flash photolysis (LFP), product analysis, and computational modeling using density functional theory (DFT). In the absence of trapping agents, diphenylnitrenium ion cyclizes to form carbazole. On the basis of laser flash photolysis experiments and DFT calculations it is argued that this process is a concerted cyclization/ proton transfer that forms the H-4a tautomer of carbazole. Additional LFP experiments and product studies show that diphenylnitrenium ion reacts with electron-rich arenes (e.g., N,N-dimethylaniline, diphenylamine, and carbazole) through an initial one-electron transfer. The radical intermediates formed in this step then couple to form dimeric products. Secondary reactions between the diphenylnitrenium ion and these dimers results in the formation of oligomeric materials.
- Kung, Andrew C.,McIlroy, Sean P.,Falvey, Daniel E.
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p. 5283 - 5290
(2007/10/03)
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- Palladium-catalyzed synthesis of pure, regiodefined polymeric triarylamines
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Triarylamine polymers were prepared by palladium-catalyzed amination of aryl halides, and the electrochemical and magnetic properties of these materials were studied. Through a careful evaluation of the catalytic and polymer chemistry involved in this pro
- Goodson, Felix E.,Hauck, Sheila I.,Hartwig, John F.
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p. 7527 - 7539
(2007/10/03)
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