- Room-temperature phosphorescent material as well as preparation method and application thereof
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The invention relates to the technical field of phosphorescent materials. The invention provides a room-temperature phosphorescent material and a preparation method and application thereof. As C-H.O. O, C-H. Experimental results show that the material pro
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Paragraph 0070-0073
(2021/09/21)
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- Nickel-Catalyzed Amination of Aryl Thioethers: A Combined Synthetic and Mechanistic Study
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Herein, we report a nickel-1,2-bis(dicyclohexylphosphino)ethane (dcype) complex for the catalytic Buchwald-Hartwig amination of aryl thioethers. The protocol shows broad applicability with a variety of different functional groups tolerated under the catalytic conditions. Extensive organometallic and kinetic studies support a nickel(0)-nickel(II) pathway for this transformation and revealed the oxidative addition complex as the resting state of the catalytic cycle. All the isolated intermediates have proven to be catalytically and kinetically competent catalysts for this transformation. The fleeting transmetalation intermediate has been successfully synthesized through an alternative synthetic organometallic pathway at lower temperature, allowing for in situ NMR study of the C-N bond reductive elimination step. This study addresses key factors governing the mechanism of the nickel-catalyzed Buchwald-Hartwig amination process, thus improving the understanding of this important class of reactions.
- Bismuto, Alessandro,Delcaillau, Tristan,Müller, Patrick,Morandi, Bill
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p. 4630 - 4639
(2020/05/19)
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- Making Copper(0) Nanoparticles in Glycerol: A Straightforward Synthesis for a Multipurpose Catalyst
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Small zero-valent copper nanoparticles (CuNPs) have been straightforwardly prepared from Cu(I) and Cu(II) precursors in glycerol and in the presence of polyvinylpyrrolidone as stabilizer. Thanks to the negligible vapor pressure of the solvent, these original nano-systems could be directly characterized in glycerol as well as in the solid state, exhibiting relevantly homogeneous colloidal dispersions, also even after catalysis. CuNPs coming from the well-defined coordination complex di-μ-hydroxobis[(N,N,N′,N′-tetramethylethylenediamine)copper(II)] chloride {[Cu(κ2-N,N-TMEDA)(μ-OH)]2Cl2} have been highly efficient in C–C and C–heteroatom bond formation processes. This new catalytic system has proved its performance in C–N couplings and in the synthesis of differently substituted propargylic amines through cross-dehydrogenative couplings, multi-component reactions such as A3 (aldehyde-alkyne-amine) and KA2 (ketone-alkyne-amine) couplings, as well as in the formation of heterocycles such as benzofurans, indolizines, and quinolines under smooth conditions. No significant copper amount was detected in the extracted organic compounds from the catalytic phase by inductively coupled plasma-atomic emission spectroscopic (ICP-AES) analyses, proving a highly efficient immobilization of copper nanoparticles in glycerol. From a mechanistic point of view, spectroscopic data (infrared and ultraviolet-visible spectra) agree with a surface-like catalytic reactivity. (Figure presented.).
- Dang-Bao, Trung,Pradel, Christian,Favier, Isabelle,Gómez, Montserrat
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p. 2832 - 2846
(2017/08/23)
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- Synthesis and structural characterization of palladium(II) thiosemicarbazone complex: Application to the Buchwald-Hartwig amination reaction
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A simple route to synthesize mononuclear palladium(II) thiosemicarbazone complex has been described. Elemental analysis, spectral methods and single crystal X-ray diffraction analysis were used to confirm the composition of the complex. The new complex acts as an active homogeneous catalyst for the Buchwald-Hartwig amination reaction of a wide range of aryl and heteroaryl halides (bromides and chlorides), including activating, neutral and deactivating substrates, with various secondary amines under optimized conditions.
- Prabhu, Rupesh Narayana,Ramesh, Rengan
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p. 1120 - 1124
(2013/03/13)
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- Transition-metal-free O-,S -, and N-arylation of alcohols, thiols, amides, amines, and related heterocycles
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A new protocol for the Ullmann-type arylation process of different aromatic heterocycles without any transition-metal catalyst, implying the use of a combination of an excess of potassium hydroxide and dimethyl sulfoxide, is described. The reaction can be performed between a broad range of starting nucleophiles including phenol, alcohols, amines, nitrogen-containing five-membered systems such as pyrazoles, imidazoles, and indoles, and amides with haloarenes, iodide and bromide derivatives giving the best results, the possible pathway involving the in situ generation of the corresponding benzyne intermediate. When the reaction was performed with 2-iodoaniline and either carboxamides or isothiocyanato derivatives, the corresponding benzoazole derivatives were obtained.
- Cano, Rafael,Ramon, Diego J.,Yus, Miguel
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experimental part
p. 654 - 660
(2011/03/20)
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- Room-temperature nickel-catalyzed amination of heteroaryl/aryl chlorides with Ni(II)-(σ-Aryl) complex as precatalyst
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The room-temperature cross-coupling of heteroaryl and aryl chlorides with secondary cyclic amines can be effected using Ni(II)-(σ-aryl) complex as pre-catalyst. Some useful aromatic and heteroaromatic amine derivatives were readily synthesized in moderate to good yields in the presence of the Ni(II)-(σ-aryl) complex/NHC/KOtBu/toluene system.
- Fan, Xin-Heng,Li, Gang,Yang, Lian-Ming
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experimental part
p. 2482 - 2484
(2011/07/07)
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- Nickel-catalyzed amination of aryl tosylates
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(Chemical Equation Presented) The cross-coupling of aryl tosylates with amines and anilines was accomplished by using a Ni-based catalyst system from the combination of Ni(II)-(σ-aryl) complexes/N-heterocyclic carbenes (NHCs). The feature, scope, and limitation of this reaction are disclosed.
- Gao, Cai-Yan,Yang, Lian-Ming
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p. 1624 - 1627
(2008/09/17)
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- Ni(II)-(σ-aryl) complex: A facile, efficient catalyst for nickel-catalyzed carbon-nitrogen coupling reactions
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(Chemical Equation Presented) trans-Haloarylbis(triphenylphosphine) nickel(II), a type of air-and moisture-stable Ni(II)-(σ-aryl) complex, was examined as catalyst precursor in the C-N coupling reaction. This type of Ni(II) pre-catalyst, associated with N-heterocyclic carbene ligands, is found to easily produce the catalytically active Ni(0) species in situ without the aid of external reductants and allows for the efficient amination of aryl chlorides with secondary cyclic amines and anilines under mild conditions.
- Chen, Chen,Yang, Lian-Ming
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p. 6324 - 6327
(2008/02/09)
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- Palladium-catalyzed selective amination of haloaromatics on KF-alumina surface
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An efficient palladium-catalyzed amination, including polyaminations of aromatic bromides mediated on a surface of KF-alumina, is reported. The solvent-free one-pot protocol avoids the use of a strong base (sodium tert-butoxide) making it applicable to substrates containing a base-sensitive functional group. It proceeds without concomitant reductive bromination and provides access to selective amination of polyhaloaromatics.
- Basu, Basudeb,Das, Pralay,Nanda, Ashish K.,Das, Sajal,Sarkar, Sajal
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p. 1275 - 1278
(2007/10/03)
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- Palladium-catalyzed amination of aryl dibromides with secondary amines: Synthetic and mechanistic aspects
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Diaminobenzenes are obtained starting from m- and p-dibromobenzenes and secondary amines in the presence of Pd(dba)2/P(o-tolyl)3 and sodium tert- butoxide in moderate to good yields. Reductive dehalogenation of aryl dibromides is a major side reaction under these conditions. The study of this reaction has shown that the formation of reductive dehalogenation products occurs according to two independent ways. The first one proceeds via the well-known β-hydride elimination from amido-coordinated palladium complexes. The second one involves the formation of hydrido palladium complexes from amino-coordinated derivatives. Although our results do not allow us to propose a detailed mechanistic scheme, they clearly show that the deprotonation step of the catalytic amination cycle has a major effect on the amine/arene ratio.
- Beletskaya, Irina P.,Bessmertnykh, Alla G.,Guilard, Roger
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p. 6393 - 6397
(2007/10/03)
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- Palladium-catalyzed multiple aryl animations of polybromobenzenes
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Morpholinobenzenes with up to four N-morpholino groups have been synthesized efficiently from the corresponding bromobenzenes via palladium catalyzed multiple aryl amination reactions. Surprisingly, hexabromobenzene (1) yielded selectively 1,2,4,5-(N,N,N,N)-tetra-(23) and 1,3,5-(N,N,N)-trimorpholinobenzene (14).
- Witulski, Bernhard,Senft, Stefan,Thum, Andreas
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p. 504 - 506
(2007/10/03)
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- Manipulation of the reduction potentials of Wurster's blue derivatives via steric and conformational effects
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Using [η6-cyclopentadienyliron]+-mediated S(N)Ar chemistry, a series of symmetrical and 2-alkyl tetra-alkyl-p-phenylenediamines have been prepared. The amine/amine.+ first redox couple has been determined for each member of the series and is influenced by remote steric, electronic, and conformational effects.
- Pearson, Anthony J.,Gelormini, Ann M.
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p. 5123 - 5126
(2007/10/03)
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- Preparation and properties of N,N,N′,N′-tetrasubstituted 1,4-benzenediamines
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The synthesis of nine different N,N,N′,N′-tetrasubstituted 1,4-benzenediamines is described. These compounds are of interest as mediators for glucose oxidase based biosensors and as donor molecules for conducting molecular solids. The electrochemical behaviour and the electronic absorption spectra have been investigated. Acta Chemica Scandinavica 1996.
- Christensen, Jorn B.,Schiodt, Niels-Christian,Bechgaard, Klaus,Buch-Rasmussen, Thomas
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p. 1013 - 1019
(2007/10/03)
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- The Willgerodt-Kindler Reactions. 6. Isomerization of the Carbonyl Group in Alkanones and Cycloalkanones
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The most unusual feature of the Willgerodt-Kindler Reactions is the facile isomerization of the carbonyl function along a chain of unbranched methylene groups, or around a cycloaliphatic ring containing several connected methylene groups.We have demonstrated that the first step in the Kindler process is the formation of enamines by reaction of the carbonyl function with secondary aliphatic amines, followed by reaction of the enamine with certain sulfur-amine catalysts to form reactive heterocyclic sulfur intermediates that facilitate the elimination-readdition of the amines reversibly along the chain.It was shown that compounds of the type R2N-S-S-NR2 are effective catalysts but not compounds of the type R2N-S-NR2.Some cyclohexanone derivatives undergo aromatization, with anomalous results in certain cases.
- Carmack, Marvin,Behforouz, Mohammad,Berchtold, Glenn A.,Berkowitz, Samuel M.,Wiesler, Donald,Barone, Ralph
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p. 1305 - 1318
(2007/10/02)
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