- 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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- Rational design of coumarin fluorophore with solvatochromism, AIE and mechanofluorochromic enhancement properties
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A new fluorophore 7-(diphenylamino)coumarin-4-yl pivalate (DPACP) with solvatochromism, aggregation-induced emission (AIE) and mechanofluorochromic (MFC) enhancement characteristics was rationally designed and synthesized by attaching bulky diphenylamine electron-donor and pivalate ester electron-acceptor to coumarin. With solvent polarity increase from n-hexane to acetonitrile, this molecular displayed a bathochromic shift in the emission wavelength (from 436 nm to 553 nm) and a decrease in the quantum yield (from 81.1% to 2.8%), indicating solvatochromic effect. Also, the AIE behaviors were observed in CH3CN/water and THF/water mixture systems. For example, the PL intensity increased 6 times in mixed solvent (CH3CN: water = 10 : 90) compared to that in pure CH3CN. Moreover, the emission of original powder samples was red-shifted (from 438 nm to 483 nm) with fluorescence enhancement (the solid-state quantum yield increase from 19% to 28%) upon grinding, and the emission behaviors of grinding powder samples could be reverted to original state by wetting with n-hexane. Furthermore, the relationship among the molecular structure, intermolecular interactions and emission properties was investigated by single-crystal diffraction analysis. DPACP had a twisted conformation because of steric hindrance from diphenylamine and pivalate ester groups, which played a decisive role in realizing AIE and MFC enhancement behaviors. The absence of π-π stacking observed in single-crystal structure was the main reason for the AIE property. The MFC enhancement property could be ascribed to the disturbance of weak electrostatic interaction of adjacent molecules upon grinding. The bulky group of pivalate ester was first used to construct MFC molecule, and this work provided insights for developing AIE and MFC materials based on conventional planar fluorophore which was always subject to ACQ effect.
- Chu, Wendao,Jiang, Weidong,Liu, Xiaoqiang,Shu, Jun,Xu, Bin,Zhang, Kaiming
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- Metal-organic frameworks derived CuONPs@C nanocatalysts for synthesizing optoelectronic triarylamine molecules
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Carbon encapsulated copper oxide nanoparticles (CuONPs@C) fabricated using copper metal organic frameworks (Cu-MOFs) used as reusable nanocatalysts in Ullmann C[sbnd]N coupling reactions for synthesizing optoelectronic triphenylamine (TPA) and carbazole (CBZ) derivatives. The formation of CuONPs in carbon matrix was confirmed by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HR-TEM). The catalytic activity of CuONPs@C was performed with diphenylamine/carbazole with substituted aryl halides in presence of mild K2CO3 base that produced triarylamines with 63–83% yields. Carbazole triarylamines exhibited strong solid state fluorescence (Φf = 14.54–36.32%) with λmax between 370 and 420 nm.
- Kundu, Anu,Kumar, Vadivel Vinod,Anthony, Savarimuthu Philip
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- Aggregation-induced emission type fluorescent materials, preparation method and application
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The invention discloses aggregation-induced emission type fluorescent materials, a preparation method and an application. The general structural formula of the fluorescent materials is shown in the description, wherein R represents a hydrogen atom, cyano
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Paragraph 0038-0040
(2019/07/05)
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- Facile construction of boranil complexes with aggregation-induced emission characteristics and their specific lipid droplet imaging applications
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A rational strategy was reported to construct boranil complexes (DPFB derivatives) with unique aggregation-induced emission effects by installing phenyl rings in the anil ligand as the intramolecular rotors. In view of the good biocompatibility and suitab
- Zhao, Na,Ma, Chengcheng,Yang, Weiyao,Yin, Wei,Wei, Jiahui,Li, Nan
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supporting information
p. 8494 - 8497
(2019/07/22)
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- Yellow-red emitting, methoxy substituted triphenylamine-based styryl derivatives: Synthesis, photophysical properties, viscosity sensitivity, aggregation induced emission, NLO properties, and DFT study
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Three novel triphenylamine based fluorescent molecular rotors (FMRs) are designed and synthesized to study the effect of auxiliary methoxy substituent on aggregation induced emission (AIE) and viscosity sensitivity. Instead of elongated, short conjugated
- Bhalekar, Sulochana,Kothavale, Shantaram,Sekar, Nagaiyan
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- Methoxy supported, deep red emitting mono, bis and tris triphenylamine-isophorone based styryl colorants: Synthesis, photophysical properties, ICT, TICT emission and viscosity sensitivity
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A novel strategy for the synthesis of triphenylamine based and methoxy supported deep red emitting push-pull chromophores is developed. The methoxy groups though not in conjugation with the acceptor exhibited a red shifted absorption and emissions (670?nm
- Kothavale, Shantaram,Sekar, Nagaiyan
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p. 116 - 130
(2016/09/02)
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- Red emitting triphenylamine based rhodamine analogous with enhanced Stokes shift and viscosity sensitive emission
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Four novel structural hybrid analogues of Rhodamine B and Rhodamine 101 are synthesized by condensing N-substituted amino phenols with keto-acids of N-substituted phenols in presence of trifluoroacetic acid and are characterized by spectroscopic methods. Triphenylamine based derivatives show large Stokes shift (47 nm–69 nm) and red shifted emission (close to Near Infrared region) as compared to parent Rhodamine B and Rhodamine 101. These N-phenyl substituted dyes exhibited negative solvatochromism and pronounced viscosity sensitivity (14–24 folds increase in emission intensity) as compared to parent rhodamines. Polarity graphs and mathematically calculated charge transfer descriptors are in good correlations with observed trends. Computed values obtained by Density Functional Theory are in good agreement with the experimental results.
- Jadhav, Amol G.,Kothavale, Shantaram,Sekar, Nagaiyan
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- Deep red emitting triphenylamine based coumarin-rhodamine hybrids with large Stokes shift and viscosity sensing: Synthesis, photophysical properties and DFT studies of their spirocyclic and open forms
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We designed and synthesized triphenylamine based and coumarin fused rhodamine hybrid dyes and characterized using 1H, 13C NMR and HR-LCMS analysis. Both the newly synthesized hybrid dyes were found to show red shifted absorption as well as emissions and large Stokes shift (40–68 nm) as compared to the small Stokes shift (25–30 nm) of reported dyes Rhodamine B and 101. Photophysical properties of these dyes were studied in different solvents and according to the solvents acidity or basicity they preferred to remain in their spirocyclic or open form in different ratio. We studied the spirocyclic as well as open form derivatives of these dyes for their viscosity sensitivity in three different mixture of solvents i.e. polar-protic [EtOH-PEG 400], polar-aprotic [toluene-PEG 400] and non-polar-aprotic [toluene-paraffin]. They are found to show very high viscosity sensitivity in polar-protic mixture of solvents [EtOH-PEG 400] and hence concluded that both polarity as well as viscosity factor worked together for the higher emission enhancement rather than only viscosity factor. As these dyes showed very high viscosity sensitivity in their spirocyclic as well as open form, they can be utilized as viscosity sensors in visible as well as deep red region. We also correlated our experimental finding theoretically by using Density Functional theory computations.
- Kothavale, Shantaram,Jadhav, Amol G.,Sekar, Nagaiyan
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p. 329 - 341
(2016/11/23)
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- Monocarboxylate transporter 1 inhibitors as potential anticancer agents
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Potent monocarboxylate transporter 1 inhibitors (MCT1) have been developed based on α-cyano-4-hydroxycinnamic acid template. Structure-activity relationship studies demonstrate that the introduction of p-N, N-dialkyl/diaryl, and o-methoxy groups into cyanocinnamic acid has maximal MCT1 inhibitory activity. Systemic toxicity studies in healthy ICR mice with few potent MCT1 inhibitors indicate normal body weight gains in treated animals. In vivo tumor growth inhibition studies in colorectal adenocarcinoma (WiDr cell line) in nude mice xenograft models establish that compound 27 exhibits single agent activity in inhibiting the tumor growth.
- Gurrapu, Shirisha,Jonnalagadda, Sravan K.,Alam, Mohammad A.,Nelson, Grady L.,Sneve, Mary G.,Drewes, Lester R.,Mereddy, Venkatram R.
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supporting information
p. 558 - 561
(2015/05/27)
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- A tuned bicyclic proazaphosphatrane for catalytically enhanced n-arylation reactions with aryl chlorides
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The N-arylation of various amines with aryl chlorides proceeded in good-to-excellent yields in the presence of P[N{(p-NMe2)C6H4CH2}CH2CH2]3N (1e, a new electron-rich proazaphosphatrane ligand) and small amounts of Pd2(dba)3 (dba = dibenzylideneacetone). This catalytic system was also very effective for the synthesis of carbazoles. An efficient palladium-catalyzed N-arylation reaction of amines under mild conditions with a tuned bicyclic proazaphosphatrane has been developed.
- Kim, So Han,Kim, Min,Verkade, John G.,Kim, Youngjo
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p. 1954 - 1960
(2015/03/18)
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- Pd-indenyl-diphosphine: An effective catalyst for the preparation of triarylamines
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A new Buchwald-type diphosphine ligand has been developed for applications in Pd-catalyzed amination reactions towards the preparation of triarylamines. The catalyst can be used to perform the amination of a diverse array of aryl and heteroaryl chlorides.
- Yan, Meng-Qi,Yuan, Jia,Pi, Yun-Xiao,Liang, Jin-Hua,Liu, Yan,Wu, Qing-Guo,Luo, Xue,Liu, Sheng-Hua,Chen, Jian,Zhu, Xiao-Lei,Yu, Guang-Ao
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supporting information
p. 451 - 454
(2016/01/12)
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- Synthesis and photoluminescent properties of 7-N,N-diphenylamino-3- benzoheterocyclic coumarin derivatives
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Two new 7-N,N-diphenylamino-3-benzoheterocyclic coumarin derivatives containing electron-transporting benzotriazolyl or benzoxazolyl moiety, 3-(1-benzotriazole)-7-N,N-diphenylaminocoumarin (BTDC) and 3-(2-benzoxazole)-7- N,N-diphenylaminocoumarin (BODC),
- Yu, Tianzhi,Zhao, Ming,Li, Aiwen,Zhao, Yuling,Zhang, Hui,Fan, Duowang
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p. 2259 - 2266
(2013/06/05)
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- Simple and convenient methods for N-arylation of heterocycles and diphenylamine
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N-Arylation of NH-heterocycles and diphenylamine with various aryl halides, using a readily accessible ligand-free potassium tert-butoxide/iron(III) oxide/dimethyl sulfoxide reagent system, gives the corresponding N-aryl derivatives in 47-97% yields. Georg Thieme Verlag Stuttgart . New York.
- Alakonda, Laxhmaiah,Periasamy, Mariappan
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experimental part
p. 1063 - 1068
(2012/05/04)
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- A multiligand based Pd catalyst for C-N cross-coupling reactions
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An alternative approach to catalyst development, which led to a Pd catalyst based on two biarylphosphine ligands for C-N cross-coupling reactions, is reported. By effectively being able to take the form of multiple catalysts this system manifests the best properties that catalysts based on either of the two ligands exhibit separately and displays the highest reactivity and substrate scope of any system that has been reported to date for these reactions.
- Fors, Brett P.,Buchwald, Stephen L.
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supporting information; experimental part
p. 15914 - 15917
(2011/01/07)
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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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- Scope and limitations of Pd2(dba)3/P(i-BuNCH 2CH2)3N-catalyzed Buchwald-Hartwig amination reactions of aryl chlorides
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Proazaphosphatrane ligands in combination with Pd2(dba) 3 generate highly active catalysts for Buchwald-Hartwig amination of aryl chlorides. In particular, commercially available P(i-BuNCH 2-CH2)3N is a highly general and efficient ligand, allowing the coupling of an electronically diverse set of aryl chlorides, including chloropyridines, with a wide variety of amines using 1 mol % of Pd at 100 °C. Either a 1:1 or 2:1 ratio of ligand to Pd was found to be effective. This catalyst system performs exceptionally well for sterically hindered substrates, even with only 0.25 mol % of Pd. It is shown that NaOH can also be used as the base (instead of NaO-t-Bu) allowing functionalized substrates to participate in these reactions.
- Urgaonkar, Sameer,Verkade, John G.
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p. 9135 - 9142
(2007/10/03)
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- Ortho-substituent effect on fluorescence and electroluminescence of arylamino-substituted coumarin and stilbene
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(Matrix presented) Newly synthesized arylamino-substituted coumarins and stilbenes show enhanced fluorescence emission (bluer and brighter) both in solution and in solid film. Pure blue efficient electroluminescence with 2.7% and 4.1% of external quantum
- Chen, Chao-Tsen,Chiang, Chih-Long,Lin, Yu-Chung,Chan, Li-Hsin,Huang, Chien-Huang,Tsai, Zong-Wei,Chen, Chin-Ti
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p. 1261 - 1264
(2007/10/03)
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- Organic light emitting displays and new fluorescent compounds
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An organic light emitting display is provided which comprises as an emitting layer a fluorescent dye having at least one amine moiety substituted with two aryl groups. Also provided are new fluorescent compounds having N-aryl substituents which exhibit reduced pH sensitivity and enhanced stability to protonation.
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- Phase-Transfer Catalysis in the Ullmann Synthesis of Substituted Triphenylamines
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A variety of substituted triphenylamine derivatives were prepared in nearly quantitative yields by the use of 18-crown-6 as a phase transfer catalyst under the Ullmann reaction conditions.
- Gauthier, Sylvie,Frechet, Jean M. J.
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p. 383 - 385
(2007/10/02)
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