Thermosensitive Gold Nanoclusters Stabilized by Well-Defined Vinyl Ether Star Polymers:  Reusable and Durable Catalysts for Aerobic Alcohol Oxidation

Kanaoka, Shokyoku; Yagi, Naoto; Fukuyama, Yukiko; Aoshima, Sadahito; Tsunoyama, Hironori; Tsukuda, Tatsuya; Sakurai, Hidehiro

doi:10.1021/ja0735599

Cited by 207 publications

(150 citation statements)

References 22 publications

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“…Aoshima and co-workers overcame these problems by using a unimolecular micellar polymer, star(EOEOVE), as a scaffold for preventing aggregation. 161 Au:star(EOEOVE) clusters could be dispersed in water at temperatures below 40°C and they oxidized benzyl alcohol into benzoic acid. Au:star(EOEOVE) clusters were precipitated above 40°C due to star(EOEOVE) having a lower critical solution temperature for phase separation in water ( Figure 17).…”

Section: Star Polymer-stabilized Au Clusters (Au:eoeove)mentioning

confidence: 99%

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Tsukuda

2012

Bulletin of the Chemical Society of Japan

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232

230

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Metal clusters consisting of fewer than 100 atoms (diameter <2 nm) are highly promising as a new class of building units for functional materials because of their novel and size-dependent properties. Nevertheless, basic and applied studies of metals clusters have been hampered by the lack of specific guidelines for design and precise synthetic methods. This account surveys recent investigations of gold clusters focusing on our effort toward an atomic-level understanding and control of their size-specific properties. We have developed a size-controlled method for synthesizing gold clusters protected by ligands, stabilized by polymers, and supported on solids. Remarkable size-effects on stabilities and various properties including catalysis were observed. Their mechanisms are discussed based on fundamental knowledge of bare gold clusters in the gas phase.

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Section: Star Polymer-stabilized Au Clusters (Au:eoeove)mentioning

confidence: 99%

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Tsukuda

2012

Bulletin of the Chemical Society of Japan

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232

230

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“…[6][7][8][9][10][11][12][13] Among various MNPs, gold nanoparticles (GNPs) are particularly interesting due to their remarkable size-and shapedependant optical and catalytic properties and numerous potential applications. [11,[14][15][16][17][18] Consequently, several methods are available in the literature to produce GNPs ranging from rods, [9,19] cubes/polyhedra, [20][21][22][23] multipods, [14,24] to triangular nanoplates [4,25] and nanoprisms. [26] Conventional approaches for the production of anisotropic GNPs rely on the availability of surfactants, polymeric or biological templates that preferentially adsorb on specific crystallographic facets and hence modify the relative growth rates of the facets.…”

Section: Introductionmentioning

confidence: 99%

Templateless Synthesis of Polygonal Gold Nanoparticles: An Unsupported and Reusable Catalyst with Superior Activity

Rashid¹,

Mandal²

2008

Adv Funct Materials

146

108

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We report the synthesis of polygonal gold nanoparticles (GNPs) by an in situ reduction technique using ferric ammonium citrate as reducing agent in absence of any surfactant or polymeric template. Transmission electron microscopic analysis and selected area electron diffraction patterns confirmed the formation of well‐crystalline polygonal GNPs grown preferentially along the (111) direction, which is consistent with the results of X‐ray diffractometry analysis. The results of control experiments of HAuCl4 with tri‐ammonium citrate in presence of different externally added metal ions like Fe3+, Ni2+, Cu2+, Zn2+, and Al3+ suggested the ion‐induced growth mechanism in the formation of polygonal GNPs. The purified polygonal GNPs were then successfully used as catalyst in the borohydride reduction of three isomeric nitrophenols and also in the aerobic oxidation of different D‐hexoses (e.g., D‐glucose, D‐mannose, D‐fructose). The catalytic activity of these polygonal GNPs is higher by a factor of 300–1000, depending on the GNP's sample type, in nitrophenol reduction compared to that of spherical GNPs. Similar activity enhancement was also observed in the aerobic oxidation of different D‐hexoses. These polygonal GNPs catalyst are very stable and could be reused several times in the borohydride reduction of nitrophenols without much losing in their virgin catalytic activity.

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“…Recently, homogeneous-heterogeneous switching catalysts have become of great interest to chemists, because they have the advantages of both homogeneous (high activity) and heterogeneous (recovery and recyclability) catalysts [1][2][3][4]. For example, Ikegami and Aoshima have developed homogeneous-heterogeneous switching catalysts by using thermosensitive polymers, such as poly(N-isopropylacrylamide) and poly[2-(2-ethoxy)ethoxyethyl vinyl ethers].…”

Section: Introductionmentioning

confidence: 99%

Application of “Boomerang” Linear Polystyrene-Stabilized Pd Nanoparticles to a Series of C-C Coupling Reactions in Water

et al. 2015

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Abstract:The application of a catch-and-release system for soluble Pd species between water (reaction medium) and polystyrene (polymer support) was examined in the Suzuki coupling reaction with 2-bromothiophene and the Heck reaction with styrene or bromobenzene. Although a slight increase in particle size was observed by TEM after re-stabilization of the Pd species on linear polystyrene, no agglomeration was observed.

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Thermosensitive Gold Nanoclusters Stabilized by Well-Defined Vinyl Ether Star Polymers: Reusable and Durable Catalysts for Aerobic Alcohol Oxidation

Cited by 207 publications

References 22 publications

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Templateless Synthesis of Polygonal Gold Nanoparticles: An Unsupported and Reusable Catalyst with Superior Activity

Application of “Boomerang” Linear Polystyrene-Stabilized Pd Nanoparticles to a Series of C-C Coupling Reactions in Water

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