Sustainable Preparation of Supported Metal Nanoparticles and Their Applications in Catalysis

Campelo, J.M.; Luna, Diego; Luque, Rafael; Marinas, J. M.; Romero, Antonio A.

doi:10.1002/cssc.200800227

Cited by 760 publications

(464 citation statements)

References 325 publications

(299 reference statements)

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“…9 Particularly, inorganic supports of high surface-area can be used to immobilize metal nanoparticles and obtain specially active and recyclable catalysts due to the higher stability and dispersion of the particles. 10 Furthermore, the combined use of water as a solvent with metal nanoparticles is a fast-growing area in response to the general upsurge of interest in minimizing the environmental impact of chemistry. 11 With these principles in mind, new possibilities have arisen for the paradigmatic click reaction.…”

Section: Introductionmentioning

confidence: 99%

Copper Nanoparticles in Click Chemistry

2015

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2The challenges of the 21 st century demand scientific and technological achievements which must be developed under sustainable and environmentally benign practices. In this vein, Click Chemistry and Green Chemistry walk hand in hand on a pathway of rigorous principles which help to safeguard the health of our planet against negligent and uncontrolled production. The copper-catalyzed azide-alkyne cycloaddition (CuAAC), the paradigm of a click reaction, is one of the most reliable and widespread synthetic transformations in organic chemistry, with multidisciplinary applications. Nanocatalysis is a Green Chemistry tool which can increase the inherent effectiveness of the CuAAC because of the enhanced catalytic activity of nanostructured metals and their plausible reutilization capability as heterogeneous catalysts.In this account, our contribution to Click Chemistry is described using unsupported and supported copper nanoparticles (CuNPs) as catalysts prepared by chemical reduction. Cu(0)NPs (3.0 ± 1.5 nm) in tetrahydrofuran were found to catalyze the reaction of terminal alkynes and organic azides, in the presence of triethylamine, at rates comparable to those achieved under microwave heating (10-30 min in most cases). Unfortunately, the CuNPs underwent dissolution under the reaction conditions and, consequently, could not be recovered. Compelling experimental evidence on the in-situ generation of highly reactive copper(I) chloride and the participation of copper(I) acetylides was provided.The supported CuNPs were found to be more robust and efficient catalyst than the unsupported counterpart in the following terms: (a) the multicomponent variant of the CuAAC could be applied, (b) with substantial decrease in the metal loading, (c) reactions could be conducted in neat water, and (d) with easy recovery and reutilization of the catalyst. In particular, the catalyst composed of oxidized CuNPs/C (Cu 2 O/CuO, 6.0 ± 2.0 nm) was shown to be highly versatile and 3 very effective in the multicomponent and regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles in water from organic halides as azido precursors; magnetically recoverable CuNPs (3.0 ± 0.8 nm)/MagSilica could be alternatively used for the same purpose under similar conditions. Incorporation of an aromatic substituent at the position 1 of the triazole could be accomplished using the same CuNPs/C catalytic system, but starting from aryl diazonium salts or anilines as azido precursors. CuNPs/C in water also catalyzed the regioselective double-click synthesis ofhydroxy-1,2,3-triazoles from epoxides. Furthermore, alkenes could be also used as azido precursors through a one-pot CuNPs/C-catalyzed azidosulfenylation-CuAAC sequential protocol, providing -methylsulfanyl-1,2,3-triazoles in a stereo-and regioselective manner. In all the types of reaction studied, CuNPs/C exhibited better behavior than some commercial copper catalysts as regards the metal loading, reaction time, yield and recyclability. Therefore, the results of this study also highlight the utility ...

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Section: Introductionmentioning

confidence: 99%

Copper Nanoparticles in Click Chemistry

2015

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“…Metallic nanoparticles have been widely studied in recent years because of their potential use as catalysts (Chimentao et al 2004;Gong and Mullins 2009;Campelo et al 2009;Li et al 2010). Silver nanoparticles are of particular interesting due to their role as substrates in the studies of catalysis (Tsujino and Matsumura 2005;Shimizu et al 2010), surface enhancement, Raman spectroscopy (Debarre et al 2004;Terekhov et al 2011) and in the biomedical field (Xu et al 2006;Liu et al 2010;Krishna Rao et al 2012).…”

Section: Introductionmentioning

confidence: 99%

A novel green one-step synthesis of silver nanoparticles using chitosan: catalytic activity and antimicrobial studies

et al. 2012

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Stable silver nanoparticles were synthesized using chitosan acting as both reducing and stabilizing agent without using any toxic chemicals. This reaction was carried out in an autoclave at a pressure of 15 psi and 120°C temperature by varying the time. The influence of different parameters such as time, change of concentration of silver nitrate and concentration of chitosan on the formation of silver nanoparticles were studied. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, Fourier transform infrared, X-ray diffraction and transmission electron microscopy. The results of catalytic reduction of 4-nitrophenol by sodium borohydride in the presence of green synthesized silver nanoparticles were presented. The antimicrobial activity of silver nanoparticles was tested against Escherichia coli and Micrococcus luteus and was found to be possessing inhibiting property.

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“…The CoFe 2 O 4 NPs not only provide a magnetic component for recyclable support [60][61][62][63] but also play a significant role to promote the oxidation reaction if they are in proximal distance with the Pt NPs.…”

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confidence: 99%

Confined Pt and CoFe₂O₄Nanoparticles in a Mesoporous Core/Shell Silica Microsphere and Their Catalytic Activity

Kang¹,

Eum²,

Lee³

et al. 2011

Bulletin of the Korean Chemical Society

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Confined Pt and CoFe 2 O 4 nanoparticles (NPs) in a mesoporous core/shell silica microsphere, Pt-CoFe 2 O 4 @meso-SiO 2 , were prepared using a bi-functional linker molecule. A large number of Pt NPs in Pt-CoFe 2 O 4 @meso-SiO 2 , ranging from 5 to 8 nm, are embedded into the shell and some of them are in close contact with CoFe 2 O 4 NPs. The hydrogenation of cyclohexene over the Pt-CoFe 2 O 4 @meso-SiO 2 microsphere at 25 o C and 1 atm of H 2 yields cyclohexane as a major product. In addition, it gives oxygenated products. Control experiments with 18O-labelled water and acetone suggest that surface-bound oxygen atoms in CoFe 2 O 4 are associated with the formation of the oxygenated products. This oxidation reaction is operative only if CoFe 2 O 4 and Pt NPs are in close contact. The Pt-CoFe 2 O 4 @meso-SiO 2 catalyst is separated simply by a magnet, which can be re-used without affecting the catalytic efficiency.

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Sustainable Preparation of Supported Metal Nanoparticles and Their Applications in Catalysis

Cited by 760 publications

References 325 publications

Copper Nanoparticles in Click Chemistry

Copper Nanoparticles in Click Chemistry

A novel green one-step synthesis of silver nanoparticles using chitosan: catalytic activity and antimicrobial studies

Confined Pt and CoFe₂O₄Nanoparticles in a Mesoporous Core/Shell Silica Microsphere and Their Catalytic Activity

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Sustainable Preparation of Supported Metal Nanoparticles and Their Applications in Catalysis

Cited by 760 publications

References 325 publications

Copper Nanoparticles in Click Chemistry

Copper Nanoparticles in Click Chemistry

A novel green one-step synthesis of silver nanoparticles using chitosan: catalytic activity and antimicrobial studies

Confined Pt and CoFe2O4Nanoparticles in a Mesoporous Core/Shell Silica Microsphere and Their Catalytic Activity

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Confined Pt and CoFe₂O₄Nanoparticles in a Mesoporous Core/Shell Silica Microsphere and Their Catalytic Activity