Heck Reactions Catalyzed by Ultrasmall and Uniform Pd Nanoparticles Supported on Polyaniline

Yu, Lei; Huang, Ya‐Ping; Zheng, Wei; Ding, Yuanhua; Su, Chenliang; Xu, Qing

doi:10.1021/acs.joc.5b01358

Cited by 116 publications

(53 citation statements)

References 47 publications

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“…As depicted in Figure , no significant loss in catalytic activity was observed after five cycles. The ICP analysis of the catalyst after first usage showed constant Pd loading from 6.0 wt. % to 5.95 wt.…”

Section: Resultsmentioning

confidence: 99%

Cyclodextrin‐Grafted Silica‐Supported Pd Nanoparticles: An Efficient and Versatile Catalyst for Ligand‐Free C−C Coupling and Hydrogenation

et al. 2016

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Silica is an extremely versatile support, which is capable of hosting metal nanoparticles (NPs) and enhancing their stability and reactivity. In this study, a novel cyclodextrin/silica support for Pd NPs, which we have denoted Pd/Si‐CD, has been prepared. The highly efficient and homogeneous impregnation of small palladium nanoparticles on this support has been carried out under conventional conditions, and ultrasound irradiation has been shown to have a beneficial effect on catalyst preparation. The catalyst exhibited excellent activity in ligand‐free C−C Suzuki and Heck couplings with a large number of aryl iodide and bromides, in which microwave irradiation use cuts down reaction time. Pd/Si‐CD have shown high activity and selectivity in the hydrogenation reaction, and the semihydrogenation of phenyl acetylene was also studied with excellent results.

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Section: Resultsmentioning

confidence: 99%

Cyclodextrin‐Grafted Silica‐Supported Pd Nanoparticles: An Efficient and Versatile Catalyst for Ligand‐Free C−C Coupling and Hydrogenation

et al. 2016

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“…As can be seen, MNP@SiO 2 -SBA exhibits a typical type-IV curve with an H2 hysteresis loop. [47,48] Appearance and increase in intensity of Pd 3d doublet corresponding to Pd(0) were observed from XPS measurements followed by a decrease in Pd(II) doublet intensity. The obtained results indicate that MNPs do not block the intrachannel space, allowing molecules to enter the channels for subsequent modifications.…”

Section: Catalyst Synthesis and Characterizationmentioning

confidence: 90%

N‐heterocyclic carbene–palladium(II) complex supported on magnetic mesoporous silica for Heck cross‐coupling reaction

Nuri

Mansoori

Bezaatpour

2019

Applied Organom Chemis

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Magnetic mesoporous silica was prepared via embedding magnetite nanoparticles between channels of mesoporous silica (SBA-15). The prepared composite (Fe 3 O 4 @SiO 2 -SBA) was then reacted with 3-chloropropyltriethoxysilane, sodium imidazolide and 2-bromopyridine to give 3-(pyridin-2-yl)-1Himidazol-3-iumpropyl-functionalized Fe 3 O 4 @SiO 2 -SBA as a supported pincer ligand for Pd(II). The functionalized magnetic mesoporous silica was further reacted with [PdCl 2 (SMe 2 ) 2 ] to produce a supported N-heterocyclic carbene-Pd(II) complex. The obtained catalyst was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, vibrating sample magnetometry, Brunauer-Emmett-Teller surface area measurement and X-ray diffraction. The amount of the loaded complex was 80.3 mg g −1 , as calculated through thermogravimetric analysis. The formation of the ordered mesoporous structure of SBA-15 was confirmed using low-angle X-ray diffraction and transmission electron microscopy. Also, X-ray photoelectron spectroscopy confirmed the presence of the Pd(II) complex on the magnetic support. The prepared magnetic catalyst was then effectively used in the coupling reaction of olefins with aryl halides, i.e. the Heck reaction, in the presence of a base. The reaction parameters, such as solvent, base, temperature, amount of catalyst and reactant ratio, were optimized by choosing the coupling reaction of 1-bromonaphthalene and styrene as a model Heck reaction. N-Methylpyrrolidone as solvent, 0.25 mol% catalyst, K 2 CO 3 as base, reaction temperature of 120°C and ultrasonication of the catalyst for 10 min before use provided the best conditions for the Heck cross-coupling reaction. The best results were observed for aryl bromides and iodides while aryl chlorides were found to be less reactive. The catalyst exhibited noticeable stability and reusability.

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“…The linking of homogeneous catalyst with the solid support renovates it to heterogeneous catalyst thereby addressing many of the above discussed shortcomings of the homogeneous catalysis. The various supports such as silica, polymer matrix, polydopamine have been used to stabilize Pd nanoparticles for a wide variety of organic transformations . However, the kinetics and catalytic activity of the catalysts immobilized in bulk heterogeneous matrices are the bottlenecks in their wide range uses unlike homogeneous catalysts.…”

Section: Introductionmentioning

confidence: 99%

Palladium Acetate and Pd Nanoparticles Loaded Hexamethylenetetramine Anchored Magnetically Retrievable Assemblies for Catalyzing Mizoroki‐Heck Type Mono and Gem‐Dicoupling Reactions

Rathod

Kumar

et al. 2020

ChemistrySelect

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Fe3O4 nanoparticles have been covalently coated and chemically modified to anchor hexamethylenetetramine (Fe3O4@HMTA) for hosting Pd catalysts such as palladium acetate and palladium nanoparticles. Thus prepared nanocatalyst assemblies have been extensively characterized for their chemical, physical, thermal and magnetic properties. The turnover number and turnover frequency of these catalysts in a model Mizoroki‐Heck coupling reaction involving 3‐acrylomorpholine and iodobenzene with a base as solvent are found to be 186 and 46 h−1, respectively, which are better than that reported in literature. This was attributed to synergistic effect of local basic environment of HMTA rich in tertiary nitrogen content. Gem‐dicoupled products are formed when reactions are performed in the presence of 1 equivalent of acrylate and 2.1 equivalents of aryl iodide, and gem‐hetero‐dicoupled product is obtained when reaction is performed in sequential manner. The mechanisms of the formation of the gem‐homo‐dicoupled and gem‐hetero‐dicoupled products have been elucidated by using the results obtained from NMR and single crystal X‐ray crystallography studies.

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Heck Reactions Catalyzed by Ultrasmall and Uniform Pd Nanoparticles Supported on Polyaniline

Cited by 116 publications

References 47 publications

Cyclodextrin‐Grafted Silica‐Supported Pd Nanoparticles: An Efficient and Versatile Catalyst for Ligand‐Free C−C Coupling and Hydrogenation

Cyclodextrin‐Grafted Silica‐Supported Pd Nanoparticles: An Efficient and Versatile Catalyst for Ligand‐Free C−C Coupling and Hydrogenation

N‐heterocyclic carbene–palladium(II) complex supported on magnetic mesoporous silica for Heck cross‐coupling reaction

Palladium Acetate and Pd Nanoparticles Loaded Hexamethylenetetramine Anchored Magnetically Retrievable Assemblies for Catalyzing Mizoroki‐Heck Type Mono and Gem‐Dicoupling Reactions

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