122-39-4Relevant articles and documents
Nano PdAu Bimetallic Alloy as an Effective Catalyst for the Buchwald-Hartwig Reaction
Chen, Zheng,Wang, Shuo,Lian, Chao,Liu, Yuxi,Wang, Dingsheng,Chen, Chen,Peng, Qing,Li, Yadong
, p. 351 - 355 (2016)
It is highly challenging but desirable to develop efficient heterogeneous catalysts for C-Cl bond activation in coupling reactions. Here, we succeeded in synthesizing bimetallic Pd-Au nanoparticles through a convenient one-pot wet chemical route. The composition and alloyed structure of the as-prepared nanoparticles were fully characterized. We have evaluated the catalytic activity of these Pd-Au alloy catalysts in Buchwald-Hartwig reactions of aryl chlorides. The excellent catalytic activity of the as-obtained Pd-Au nanoparticles indicates that exploiting the catalytic power of nano-alloy catalysts could enable effective C-Cl bond activation suitable for cross-coupling reactions.
A practical removal method of camphorsultam
Hasegawa, Tomoyuki,Yamamoto, Hisashi
, p. 882 - 884 (1998)
A mild and efficient removal of camphorsultam was realized using tetrabutylammonium hydrogen peroxide as a key reagent.
A base-free Chan–Lam reaction catalyzed by an easily assembled Cu(II)-carboxylate metal-organic framework
Ma, Ruixuan,Qin, Jianhua,Shi, Lei,Zhang, Xinhai
, p. 795 - 799 (2021)
A new copper(II) metal-organic framework is constructed as a sustainable copper heterogeneous catalyst. Cu-DPTCA, with high catalytic activity, can effectively promote the Chan–Lam coupling reaction of arylboronic acids and amines without adding any base or additive.
PHOTOCHEMISTRY OF 1,3-DIPHENYLTRIAZENE IN VARIOUS MEDIA. II: SOLID STATE PHOTOLYSIS.
Baro,Dudek,Luther,Troe
, p. 1161 - 1164 (1983)
Solid 1,3-diphenyltriazene (DPT) has been photolyzed at 290 nm and 360 nm. The distribution of the photoproducts showed that recombination of the radicals produced after photochemical excitation was governed by a 'cage effect' favoring a minimum of motion of the recombining radicals. In many details the results differ from observations on the photochemistry of DPT in liquid solutions. The photolysis of DPT in polymethylmethacrylate films, however, resembles the photochemistry of DPT in liquid solutions.
One-Step Pyrolysis Preparation of 1.1.1 Oriented Gold Nanoplatelets Supported on Graphene and Six Orders of Magnitude Enhancement of the Resulting Catalytic Activity
Primo, Ana,Esteve-Adell, Ivan,Coman, Simona N.,Candu, Natalia,Parvulescu, Vasile I.,Garcia, Hermenegildo
, p. 607 - 612 (2016)
Pyrolysis of chitosan films containing Au3+ renders 1.1.1 oriented Au nanoplatelets (20 nm lateral size, 3-4 nm height) on a few layers of N-doped graphene (${overline {{rm{Au}}} }$/fl-G), while the lateral sides were 0.0.1 oriented. Comparison of the catalytic activity of ${overline {{rm{Au}}} }$/fl-G films with powders of unoriented Au NPs supported on graphene showed that ${overline {{rm{Au}}} }$/fl-G films exhibit six orders of magnitude enhancement for three gold-catalyzed reactions, namely, Ullmann-like homocoupling, C-N cross coupling, and the oxidative coupling of benzene to benzoic acid. This enhancement is the result of the defined morphology, facet orientation of Au nanocrystals, and strong gold-graphene interaction.
Palladium-Imidazolium N-Heterocyclic Carbene-Catalyzed Carbonylative Amidation with Boronic Acids, Aryl Diazonium Ions, and Ammonia
Ma, Yudao,Song, Chun,Chai, Qiang,Ma, Changqin,Andrus, Merritt B.
, p. 2886 - 2889 (2003)
Aryl diazonium tetrafluoroborates have been coupled with arylboron compounds, carbon monoxide, and ammonia to give aryl amides in high yields. A saturated N-heterocyclic carbene (NHC) ligand, H2IPr was used with palladium(II) acetate to give the active catalyst. A mechanism is proposed for this novel four-component coupling reaction.
Replacing sulfonate by carboxylate: Application of pyridyliminocarboxylato copper(II) complexes in rac-lactide polymerization and Chan-Evans-Lam coupling
Hardouin Duparc, Valérie,Dimeck, Clémentine,Schaper, Frank
, p. 178 - 190 (2019)
Copper(II) complexes carrying pyridylmethyleneaminobenzoate or-propanoate ligands, LCuX, were prepared in one-pot reactions from pyridinecarboxaldehyde, aminobenzoic acid or β-alanine, and CuX2 (X = Cl, NO3, OAc, or OTf). All complexes were characterized by single-crystal X-ray diffraction studies and formed either dimers, tetramers, or coordination polymers. Attempted preparation of the respective alkoxide complexes, LCu(OR), was unsuccessful, but use of LCuX/NaOMe mixtures in rac-lactide polymerization indicated under some conditions coordination-insertion polymerization via a copper alkoxide as the mechanism. The complexes performed poorly in rac-lactide polymerization, showing low activities (12 h to completion at 140 °C), low to moderate heterotacticity (Pr = 0.6-0.8), and poor polymer molecular weight control (intramolecular transesterification). They were competent catalysts for Chan-Evans-Lam couplings with phenylboronic acid, without any indication of side reactions such as deboration or aryl homocoupling. The complexes were active in undried methanol, without addition of base, ligand, or molecular sieves. Aniline, n-octylamine, and cyclohexylamine were coupled quantitatively under identical reaction conditions. There is only little influence of the anion on activities (less than a factor of 2) but a strong influence on induction periods. The complexes were not active in CEL coupling with alcohols, phenols, or alkylboronic acids.
Reactions of Diarylnitrenium Ions with Electron Rich Alkenes: An Experimental and Theoretical Study
Moran, Ricardo J.,Cramer, Christopher,Falvey, Daniel E.
, p. 2742 - 2751 (1997)
Photolysis of N-(diphenylamino)-2,4,6-trimethylpyridinium tetrafluoroborate (1a) and N-[bis(4-methylphenyl)amino]-2,4,6-trimethylpyridinium salt (1b) gives products attributable to diarylnitrenium ion (Ar2N+, 2). The major products of these reactions include products from nucleophilic addition of various π-nucleophiles (e.g. electron rich alkenes) to the ortho and para positions of one of the phenyl rings. Nanosecond and EPR spectroscopy show that radicals also form. These radicals are thought to give rise to the diarylamines isolated as minor products from the photolysis of la and 1b. In addition to the para addition products and Ph2NH, N-phenylindoles and N-phenylindolinones are isolated when silyl enol ethers and silyl ketene acetals are used as trapping agents, respectively. The indoles and indolinones are generated from initial addition of the nucleophile to the ortho position on 2 followed by cyclization of the resulting intermediate. A product resulting from N addition of the nucleophile to 2 is isolated only when silyl ketene acetals are used. A number of electronic sturcture calculations at different levels of molecular orbital and density functional theory were carried out on Ph2N+. There do not seem to be effects associated with either the charge distribution or the LUMO that would strongly influence ortho/para/N selectivity in nucleophilic trapping. Laser flash photolysis on la provides absolute rate constants for the nucleophilic addition of various alkenes to Ph2N+. These fall in the range of 109-1010 M-1 s-1 and correlate with the oxidation potential of the alkene. From these data it is clear that the more easily oxidized the alkene the faster it will react with Ph2N+.
Theoretical and Experimental Studies: Cu(I)/Cu(II) Catalytic Cycle in CuI/Oxalamide-Promoted C-N Bond Formation
Morarji, Devita V.,Gurjar, Kamlesh K.
, (2019)
In modern Ullmann-Goldberg reactions, cheaper aryl chlorides are poor substrates. Recently, attention has been paid to facile CuI/oxalamide-promoted arylation of heteroatoms (N, O, and S) using cheaper aryl chlorides. However, the mechanism of the reaction and the role of oxalamides have not yet been investigated. In the present investigation, theoretical (density functional theory) and supporting in situ 1H NMR spectroscopy, UV-vis spectroscopy, Fourier transform infrared spectroscopy, and cyclic voltammetry studies have been performed to provide insight into the various aspects of the mechanism. Five different possible pathways have been investigated. [LCu(NHNu)] is the active copper catalytic species, in which L (oxalamide) coordinates Cu(I) through both C=O groups. Our studies show that the reaction follows an outer-sphere single-electron transfer pathway. Moreover, these studies also address the reason for the deactivation of a copper catalyst.
Copper(II) hydroxide complexes of N-heterocyclic carbenes and catalytic oxidative amination of arylboronic acids
Liu, Bo,Liu, Bin,Zhou, Yongbo,Chen, Wanzhi
, p. 1457 - 1464 (2010)
Reactions of the imidazolium salts or their corresponding silver carbene complexes with copper powder afforded unusual copper(II) hydroxide complexes of N-heterocyclic carbenes: [Cu2(μ-OH)(L1)](PF6) 2 (2; L1 = 3,5-bis(N-picolylimidazolylidenylmethy1)pyrazolate), [Cu4(μ3-OH)2(L2)2](PF 6)4 (3; L2 = 3,5-bis(N-pyridylimidazolylidenylmethy1) pyrazolate), and [Cu4(μ3-OH)2(L3) 2](PF6)4 (4; L3 = 3,5-bis(N- pyrimidylimidazolylidenylmethy1)pyrazolate). The same reaction of 3,5-bis(N-thiophenylimidazoliumylmethy1)pyrazole yielded a dinuclear Cu(II)-NHC complex, [Cu2(L4)2] (PF6)2 (5; L4 = 3,5-bis(N-thiophenylimidazolylidenylmethy1)pyrazolate). The complexes have been fully characterized by X-ray diffraction analysis, elemental analysis, and IR and ESI-MS spectra. A catalytic study shows that complex 4 is highly active in the N-arylation reactions of imidazoles and aromatic amines with arylboronic acids in methanol at room temperature under base-free conditions.
