Zufall und Unvermeidlichkeit: Die Entdeckung der Goldkatalyse

Haruta, Masatake

doi:10.1002/ange.201305987

Cited by 17 publications

(4 citation statements)

References 47 publications

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“…[1] Au-based catalysts have attracted much attention for the aerobic oxidation of alcohols, owing to their high activity and selectivity. [5] The size of the Au nanoparticles is one of the most important factors in determining the catalytic behavior of Au-based catalysts. One advantage of this reaction is the avoidance of the problems of over-oxidation and explosion, which may occur during the large-scale aerobic oxidation process, because of the co-existence of oxygen and organic reactants or solvents.…”

Section: Introductionmentioning

confidence: 99%

“…[2] In addition to aerobic oxidation, the oxidant-free and acceptor-free dehydrogenation reaction provides another environmentally benign route for the conversion of alcohols into aldehydes or ketones. [5,6] Some studies have been devoted to elucidating the size effect in the Au-catalyzed aerobic oxidation of alcohols, but the conclusions are quite controversial. Moreover, it has been pointed out that the oxidant-and acceptor-free dehydrogenation of alcohols may provide a promising route for H 2 synthesis and storage.…”

Section: Introductionmentioning

confidence: 99%

“…[4b-g] Au catalysis has become a "hot" research area since the discovery that Au particles a few nanometers in size are catalytically active. [5] The size of the Au nanoparticles is one of the most important factors in determining the catalytic behavior of Au-based catalysts. [5,6] Some studies have been devoted to elucidating the size effect in the Au-catalyzed aerobic oxidation of alcohols, but the conclusions are quite controversial.…”

Section: Introductionmentioning

confidence: 99%

“…[5] The size of the Au nanoparticles is one of the most important factors in determining the catalytic behavior of Au-based catalysts. [5,6] Some studies have been devoted to elucidating the size effect in the Au-catalyzed aerobic oxidation of alcohols, but the conclusions are quite controversial. Tsukuda and co-workers studied the size effect of Au nanoclusters that were stabilized by poly(N-vinyl-2-pyrrolidone) in the aerobic oxidation of p-hydroxybenzyl alcohol and observed some structure-sensitivity for this system.…”

Section: Introductionmentioning

confidence: 99%

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A Comparative Study of Size Effects in the Au‐Catalyzed Oxidative and Non‐Oxidative Dehydrogenation of Benzyl Alcohol

Chen¹,

Fang²,

Zhang³

et al. 2014

Chemistry An Asian Journal

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A hydrotalcite-supported gold catalyst has been found to be efficient for both oxidative and non-oxidative conversions of benzyl alcohol into benzaldehyde. In both cases, the reaction rates were dependent on the size of the Au particles, but the size dependence for the non-oxidative reaction was more pronounced. Our analyses on the intrinsic rates of different sites suggested that all of the atoms on the Au surfaces participated in the oxidative reaction, whereas the edge and corner Au atoms predominantly contributed to the non-oxidative reaction, and that the terrace atoms were at least two orders of magnitude less active than the edge or corner atoms. In both cases, the rate-determining step was CH bond cleavage. The presence of oxygen significantly enhanced the reaction rate. Herein, we propose that the non-oxidative reaction proceeds through a β-H elimination step by the low-coordination-number edge and corner Au atoms, whereas the active oxygen species, which are even generated on the terrace Au atoms, might assist CH bond cleavage under oxidative conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Comparative Study of Size Effects in the Au‐Catalyzed Oxidative and Non‐Oxidative Dehydrogenation of Benzyl Alcohol

Chen¹,

Fang²,

Zhang³

et al. 2014

Chemistry An Asian Journal

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Highly Efficient Transition Metal Nanoparticle Catalysts in Aqueous Solutions

et al. 2016

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Al igand design is proposed for transition metal nanoparticle (TMNP) catalysts in aqueous solution. Thus, at ris(triazolyl)-polyethylene glycol (tris-trz-PEG) amphiphilic ligand, 2,i su sed for the synthesis of very small TMNPs with Fe,C o, Ni, Cu, Ru, Pd, Ag, Pt, and Au. These TMNP-2 catalysts were evaluated and compared for the model 4-nitrophenol reduction, and proved to be extremely efficient. High catalytic efficiencies involving the use of only afew ppm metal of PdNPs,RuNPs,and CuNPs were also exemplified in Suzuki-Miyaura, transfer hydrogenation, and click reactions, respectively.Since the seminal discoveries by Haruta [1] and Hutchings, [2] catalysis of chemical reactions by transition metal nanoparticles (TMNPs) has attracted considerable interest owing to its efficiency, greenness,c onvenient use,a nd improved understanding of reaction mechanisms. [3][4][5][6][7][8][9] Thes upport and medium have been shown to play an essential role in TMNP catalysis,but relatively little attention has been paid to TMNP surface ligand design. Yetb oth TMNP formation in micelles or inverted micelles and catalysis therein are also strongly dependent on the stereoelectronic parameters of the stabilizing agents. [10][11][12][13] Catalysis in water offers great advantages in terms of green chemistry,a nd has recently been actively investigated. [14][15][16][17][18][19][20][21] Fori nstance,a mphiphilic dendrimers are unimolecular micelles, [18][19][20] and this property has recently been exploited for catalysis in water with little as parts per million (ppm) amounts of molecular or TMNP catalysts.[21] The synthesis and use in catalysis of amphiphilic dendrimers as nanoreactors represents avery productive sophistication, but it is time-consuming,a nd one can conceptualize ar elated approach using simpler amphiphilic ligands.Toward this goal, we suggest the design of weak, but multidentate bulky ligands that offer both easy displacement from TMNP surface by substrates for catalysis and sufficient TMNP stabilization. As ar esult, we report the amphiphilic tripodal ligand tris(1,2,3-triazolyl)-polyethylene glycol (tristrz-PEG), 2,t hat led to the synthesis of very small TMNPs with various transition metals (Fe, Co,Ni, Cu, Ru, Ag, Pt, Pd, and Au). These TMNP-2 complexes are shown to be remarkably efficient catalysts of several major green reactions.F irst, 4-nitrophenol (4-NP) reduction by NaBH 4 in water was used as am odel NP surface reaction to demonstrate the catalyst efficiencya nd compare all of these metals with one another. Then RuNP-catalyzed transfer hydrogenation of nitrobenzene with i-propanol as the hydrogen source in water/i-propanol, PdNP-catalyzed Suzuki-Miyaura crosscoupling reaction between bromobenzene and phenylboronic acid in water/EtOH, and CuNP-catalyzed azide-alkyne 1,3-cycloaddition (CuAAC, click) reaction in water were shown to work using extremely low amounts (down to afew ppm) of catalysts.Thes ynthesis of the tris-trz-PEG ligand 2 starts with the preparation of tris(1-benzyl-1H-1,2,3-triazo...

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ZnAl‐Hydrotalcite‐Supported Au₂₅Nanoclusters as Precatalysts for Chemoselective Hydrogenation of 3‐Nitrostyrene

et al. 2017

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Chemoselective hydrogenation of 3-nitrostyrene to 3-vinylaniline is quite challenging because of competitive activation of the vinyl group and the nitro group over most supported precious-metal catalysts.Aprecatalyst comprised of thiolated Au 25 nanoclusters supported on ZnAl-hydrotalcite yielded gold catalysts of aw ell-controlled size( ca. 2.0 nm)even after calcination at 500 8 8C. The catalyst showed excellent selectivity (> 98 %) with respect to 3-vinylaniline,a nd complete conversion of 3-nitrostyrene over broad reaction duration and temperature windows.T his result is unprecedented for gold catalysts.I nc ontrast to traditional catalysts,t he gold catalyst is inert with respect to the vinyl group and is only active with regard to the nitro group,asdemonstrated by the results of the control experiments and attenuated total reflection infrared spectra. The findings may extend to design of gold catalysts with excellent chemoselectivity for use in the synthesis of fine chemicals.

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Zufall und Unvermeidlichkeit: Die Entdeckung der Goldkatalyse

Cited by 17 publications

References 47 publications

A Comparative Study of Size Effects in the Au‐Catalyzed Oxidative and Non‐Oxidative Dehydrogenation of Benzyl Alcohol

A Comparative Study of Size Effects in the Au‐Catalyzed Oxidative and Non‐Oxidative Dehydrogenation of Benzyl Alcohol

Highly Efficient Transition Metal Nanoparticle Catalysts in Aqueous Solutions

ZnAl‐Hydrotalcite‐Supported Au₂₅Nanoclusters as Precatalysts for Chemoselective Hydrogenation of 3‐Nitrostyrene

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Zufall und Unvermeidlichkeit: Die Entdeckung der Goldkatalyse

Cited by 17 publications

References 47 publications

A Comparative Study of Size Effects in the Au‐Catalyzed Oxidative and Non‐Oxidative Dehydrogenation of Benzyl Alcohol

A Comparative Study of Size Effects in the Au‐Catalyzed Oxidative and Non‐Oxidative Dehydrogenation of Benzyl Alcohol

Highly Efficient Transition Metal Nanoparticle Catalysts in Aqueous Solutions

ZnAl‐Hydrotalcite‐Supported Au25Nanoclusters as Precatalysts for Chemoselective Hydrogenation of 3‐Nitrostyrene

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Product

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ZnAl‐Hydrotalcite‐Supported Au₂₅Nanoclusters as Precatalysts for Chemoselective Hydrogenation of 3‐Nitrostyrene