19482-11-2Relevant articles and documents
Transformation of Trifluorotoluenes Triggered by Titanium(IV) Chloride-Catalyzed Hydrodefluorination using Hydrosilanes
Yamada, Takayuki,Saito, Kodai,Akiyama, Takahiko
, p. 62 - 66 (2016)
The titanium tetrachloride-catalyzed hydrodefluorination reaction of trifluorotoluene derivatives was developed using triethylsilane as the reducing agent. The reaction produced various toluene derivatives with high chemoselectivities by means of readily accessible reagents. This hydrodefluorination process was extended to the intramolecular Friedel-Crafts benzylation reaction, furnishing polycyclic aromatics of various ring sizes in good yields.
Pillar[5]arene-based N-heterocyclic carbene ligand for Pd-catalysed Suzuki reaction
Xiao, Xue-Dong,Liu, Jia-Qi,Bai, Ya-Li,Wang, Rui-Hua,Wang, Jun-Wen
, p. 29 - 36 (2017)
A pillar[5]arene-based N-heterocyclic carbene ligand was prepared by reaction of bromoethoxy pillar[5]arene with excess 1-methylimidazole at 130?°C in the absence of solvent and used as a catalyst for the Suzuki coupling reaction. Excellent yields were obtained when the Suzuki reactions were carried out under ambient atmosphere in ethanol, employing 0.2?mol% ligand, 1?mol% PdCl2(CH3CN)2 and 1.5?mmol of K2CO3. The novel pillar[5]arene-based imidazolium salt is a promising material for the construction of highly active supramolecular catalytic systems.
Engineering of highly active Au/Pd supported on hydrogenated urchin-like yolk@shell TiO2 for visible light photocatalytic Suzuki coupling
Rohani, Sahar,Ziarati, Abolfazl,Ziarani, Ghodsi Mohammadi,Badiei, Alireza,Burgi, Thomas
, p. 3820 - 3827 (2019)
Efficient smart photocatalysts and their surface engineering are necessary for the effective conversion of light energy into chemical energy in photocatalyzed organic reactions. Herein, we designed a hydrogenated urchin-like yolk@shell TiO2 structure decorated with Au and Pd nanoparticles (HUY@S-TOH@AuPd) as a robust photocatalyst for C-C coupling reactions. The resulting architecture exhibits considerable photocatalytic performance in Suzuki coupling reactions under visible light irradiation with a turnover frequency (TOF) value as high as 7095 h-1. The beauty of this engineered structure lies on the following four points: (I) the urchin-like structure provided a large accessible surface area for high light harvesting as well as high noble metal anchoring; (II) the yolk@shell mesoporous architecture improved the absorption of light by multiple scattering; (III) the presence of Ti3+ species on the surface of TiO2 decreased the band gap of the structure to the visible region; (IV) the enriched electron density of Pd through the injection of hot electrons from Au as well as the flow of electrons from the titanium dioxide semiconductor to the metals accelerated the rate-determining step. The merging of bimetallic plasmonic nanoparticles and urchin like yolk-shell hydrogenated titanium dioxide architecture can open an avenue for designing photocatalysts with high stability and promising activity as well as high direct harvesting of visible light for a broad range of photocatalytic organic reactions.
Mesoporous palladium-copper ferrites as highly efficient and magnetically separable catalysts for Suzuki coupling reaction
Tong, Jinhui,Su, Lingdi,Bo, Lili,Cai, Xiaodong,Zhang, Qianping,Wang, Qizhao
, p. 240 - 246 (2016)
Mesoporous Cu-Pd ferrites were prepared by using MCM-41 and SBA-15 mesoporous molecular sieves as hard templates and well characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ICP-atomic emission spectroscopy, N2 adsorption-desorption and X-ray photoelectric spectroscopy (XPS). Compared with samples prepared by the sol-gel auto-combustion methods, the as-prepared mesoporous ferrites have shown uniform pore size and much higher specific surface areas. The samples showed a remarkably high activity in connection with the Suzuki coupling reaction, especially Cu0.99Pd0.01Fe2O4 prepared by using MCM-41 as template obtained an excellent TOF as high as 36.9 × 103 h-1 and no obvious decrease in the activity was observed after ten consecutive runs.
Palladium(II) thiosemicarbazone-catalyzed Suzuki-Miyaura cross-coupling reactions of aryl halides
Pandiarajan, Devaraj,Ramesh, Rengan,Liu, Yu,Suresh, Rajamanickam
, p. 33 - 37 (2013)
A new air-and moisture-stable palladium(II) complex bearing pyridoxal thiosemicarbazone ligand has been synthesized. The synthesized complex was characterized by analytical and spectral methods. The molecular structure of the complex was confirmed by X-ray diffraction method. The palladium(II) complex was used as potential catalyst for Suzuki-Miyaura coupling reaction of several aryl halides under optimized conditions.
Room-temperature Suzuki-Miyaura reaction catalyzed by palladium nanoparticles in lactate-anion ionic liquid
Wang, Furong,Tang, Sisi,Ma, Hao,Wang, Lefu,Li, Xuehui,Yin, Biaolin
, p. 1225 - 1232 (2014)
A palladium nanoparticle catalyst (PdNPs[Bmim]Lac) has been prepared by a simple, mild and efficient chemical approach using 1-butyl-3-methylimidazolium lactate ([Bmim]Lac) ionic liquid) as a stabilizer. This catalyst exhibits excellent activity, stability, recyclability and simple manipulation in Suzuki-Miyaura reactions at room temperature in air.
DNA as a bioligand supported on magnetite for grafting palladium nanoparticles for cross-coupling reaction
Kandathil, Vishal,Kempasiddaiah, Manjunatha,Nataraj, Sanna Kotrappanavar,Patil, Siddappa A.,Somappa, Sasidhar Balappa
, (2020)
The utilization of deoxyribonucleic acid (DNA) in nanotechnology is a promising area of research wherein the distinct properties of DNA are exploited for the design and development of new materials and applications. The biodegradability and natural profusion of DNA makes it highly suitable for use in various fields. In this report, we have treated DNA as a bioligand, supported on functionalized magnetite for the grafting of palladium (Pd) nanoparticles to make Pd-DNA bio-nanocatalyst. The Pd-DNA was subjected to Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Brunauer–Emmett–Teller, energy dispersive X-ray spectroscopy, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and inductively coupled plasma optical emission spectrometry analysis. The prepared Pd-DNA was found to be highly efficient in catalyzing Suzuki–Miyaura cross-coupling reaction with excellent yields when compared with commercially available palladium-based catalysts. Also, the Pd-DNA could be easily recovered from the reaction mass using an external magnet and recycled up to six times without substantial loss of activity. Furthermore, Felbinac, a non-inflammatory drug, was synthesized in quantitative yields using the Pd-DNA bio-nanocatalyst.
Palladium nanoparticles supported on functional ionic liquid modified magnetic nanoparticles as recyclable catalyst for room temperature Suzuki reaction
Wang, Jiayi,Xu, Beiling,Sun, Haiyang,Song, Gonghua
, p. 238 - 241 (2013)
Palladium nanoparticles were successfully immobilized on amine functionalized ionic liquid modified magnetic nanoparticles leading to a magnetically recoverable Pd catalyst, which exhibits high catalytic activity in the Suzuki coupling reaction at room temperature. The catalyst can be separated from the reaction mixture by applying a permanent magnet externally and can be reused for several times without significant loss of activity.
Synthesis, characterization and evaluation of bulky bis(pyrazolyl)palladium complexes in Suzuki-Miyaura cross-coupling reactions
Ocansey, Edward,Darkwa, James,Makhubela, Banothile C. E.
, p. 13826 - 13834 (2018)
Pyrazole-containing compounds have been used in recent times as ligands to stabilize metal complexes used as pre-catalysts in cross-coupling reactions. With various substituents at various positions in the pyrazole ring, the overall electrophilic and steric properties of the metal complexes can be fine-tuned. Herein, we report the synthesis of bulky pyrazole-based ligands by condensation of methyl 4-(bromomethyl)benzoate or benzyl bromide with various substituted pyrazole compounds. These ligands were utilised in the synthesis of bis(pyrazolyl)palladium(ii) complexes. The complexes' catalytic activity in Suzuki-Miyaura cross-coupling reactions was evaluated. Phenyl bearing pre-catalyst 7, at a catalyst loading of 0.33 mol%, successfully converted 98% of bromobenzene and phenylboronic acid to biphenyl in 4 h at 140 °C, while the tertiary butyl bearing pre-catalyst 8 converted up to 81% of the same substrates to biphenyl. An increase in conversion was seen for all pre-catalysts when an electron-withdrawing substituent was present on the aryl halide substrate, and the opposite was observed when the electron-withdrawing group was present on the phenyl boronic acid.
Fe3O4-SAHPG-Pd0 nanoparticles: A ligand-free and low Pd loading quasiheterogeneous catalyst active for mild Suzuki–Miyaura coupling and C-H activation of pyrimidine cores
Azizollahi, Hamid,Eshghi, Hossein,García-López, José-Antonio
, (2020/09/17)
This paper reports a green magnetic quasiheterogeneous efficient palladium catalyst in which Pd0 nanoparticles have been immobilized in self-assembled hyperbranched polyglycidole (SAHPG)-coated magnetic Fe3O4 nanoparticles (Fe3O4-SAHPG-Pd0). This catalyst has been used for effective ligandless Pd catalyzed Suzuki–Miyaura coupling reactions of different aryl halides with substituted boronic acids at room temperature and in aqueous media. Herein, SAHPG is used as support; it also acts as a reducing agent and stabilizer to promote the transformation of PdII to Pd0 nanoparticles. Also, this environmental friendly quasiheterogeneous catalyst is employed for the first time in the synthesis of new pyrimido[4,5-b]indoles via oxidative addition/C-H activation reactions on the pyrimidine rings, which were obtained with higher yield and faster than when Pd(OAc)2 was used as the catalyst. Interestingly, the above-mentioned catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled several times with no significant decrease in the catalytic activity.
Hexagonal Boron Nitride Supported N-Heterocyclic Carbene-Palladium(II): A New, Efficient and Recyclable Heterogeneous Catalyst for Suzuki–Miyaura Cross-Coupling Reaction
Antony, Arnet Maria,Kandathil, Vishal,Kempasiddaiah, Manjunatha,Sasidhar,Patil, Shivaputra A.,Patil, Siddappa A.
, p. 1293 - 1308 (2020/10/06)
Abstract: In this study, a new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed and synthesized. The structure of the h-BN@NHC-Pd heterogeneous catalyst was characterized by various techniques such as Fourier transform infrared spectra (FT-IR), ultraviolet–visible spectroscopy (UV–Visible), inductively coupled plasma-optical emission spectroscopy (ICP-OES), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller surface area analysis (BET). Then catalytic activity of h-BN@NHC-Pd heterogeneous catalyst was studied in the Suzuki–Miyaura cross-coupling reactions between aryl halides and arylboronic acids in aqueous medium at room temperature. The effects of varying solvents, bases, temperature, time and catalytic ratios on the performance of the Suzuki–Miyaura cross-coupling reaction were investigated. Moreover, h-BN@NHC-Pd heterogeneous catalyst could be easily recovered through simple filtration or centrifugation method and could be reused five times without significant loss of its catalytic efficiency. Furthermore, stability of the h-BN@NHC-Pd heterogeneous catalyst after recycling was confirmed through FESEM and FT-IR techniques. The h-BN@NHC-Pd heterogeneous catalyst shows remarkable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easily separable and high stability without leaching. Graphic Abstract: A new stable and powerful hexagonal boron nitride supported N-heterocyclic carbene-palladium(II) complex (h-BN@NHC-Pd) heterogeneous catalyst was designed, synthesized, characterized and catalytic activity was studied in the Suzuki–Miyaura cross-coupling reactions. [Figure not available: see fulltext.]
