Giant palladium clusters as catalysts of oxidative reactions of olefins and alcohols

Варгафтик, М. Н.; Zagorodnikov, V. P.; Stolarov, Igor P.; Моисеев, И. И.; Kochubey, D.I.; Likholobov, V. A.; Chuvilin, Andrey; Zamaraev, K. I.

doi:10.1016/0304-5102(89)80066-5

Cited by 188 publications

(104 citation statements)

References 14 publications

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“…The same general procedure was used as above except isolated Pd(DMAP) 4 (OH) 2 complex crystals were used to catalyse the reactions instead of the DMAP stabilised palladium nanoparticle dispersion. The complex crystals were dissolved in water prior to the commencement of the Suzuki reactions.…”

Section: Catalysed Suzuki Reactionsmentioning

confidence: 99%

“…Following this, a sixth reaction was carried out for 2 hours and this reaction mixture was also filtered while hot through a polycarbonate membrane filter (Whatman-UK, 0.2 µm pore diameter). These several reaction cycles were used in order to ensure that any Pd(DMAP) 4 (OH) 2 complex present in the initial nanoparticle dispersion was fully removed from the catalyst. It is noted from above that one reaction cycle was sufficient to remove significant catalytic activity (and presumably Pd complex) from the MWCNT_Complex compositeand it was assumed that the three further reaction cycles would be sufficient to ensure that all of the Pd(II) complexes are removed from the MWCNT/Pd-DMAP NP composite.…”

Section: Interestingly De Vries Et Al Have Identified the Catalysis mentioning

confidence: 99%

“…In order to determine whether these Pd(II) complexes are the active species evolved during the aging of the nanoparticle dispersions, one complex (a square planar Pd(DMAP) 4 ion coordinated to two OH -counter ions), which could be isolated from the aged dispersions [20] was used as a catalyst to promote the reactions of interest.…”

Section: Activity Of Pd(dmap) 4 (Oh) 2 Complexmentioning

confidence: 99%

“…Many different types of transition metal nanoparticles have been used to catalyse a variety of synthetic chemical reactions including the Hydrogenation, Heck, Suzuki, Sonagashiri and Stille reactions [1][2][3][4]. Progress in the field has been rapid with a multitude of reactions now known to be catalysed by nanoparticles stabilised by a variety of surfactants [5], thiols [6], polymers (PVP, etc) [7][8][9] and dendrimers [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Suzuki coupling activity of an aqueous phase Pd nanoparticle dispersion and a carbon nanotube/Pd nanoparticle composite

Sullivan¹,

Flanagan²,

Hain

2009

Catalysis Today

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An aqueous phase dispersion of Pd nanoparticles stabilised by 4-Dimethylaminopyridine (DMAP) promotes model Suzuki coupling reactions. The dispersion contains Pd nanoparticles of 3.4 0.5 nm and a Pd(II) species (Pd(DMAP) 4 (OH) 2 ) which forms following aerobic oxidation of the nanoparticles.The activity of the nanoparticle dispersion in promoting the Suzuki reactions is directly proportional to the size of the halogen on the substrate (as is usual for these coupling reactions) and also to the age of the nanoparticle dispersion.The Pd(DMAP) 4 (OH) 2 complex can be isolated from the dispersion and is found to be very active in promoting the reactions. Its formation following aerobic oxidation of the nanoparticles is proposed as the reason for the improved activity of the dispersion with age.The nanoparticles present in the dispersion can, through displacement of the stabilising ligand, be immobilised onto functionalised Multi Wall Carbon Nanotubes (MWCNT) and the composite formed is an active and recyclable catalyst. This MWCNT/Pd-DMAP NP composite acts as a reservoir of dissolved Pd species, which function as homogeneous catalysts under reaction conditions.

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Section: Catalysed Suzuki Reactionsmentioning

confidence: 99%

Section: Interestingly De Vries Et Al Have Identified the Catalysis mentioning

confidence: 99%

Section: Activity Of Pd(dmap) 4 (Oh) 2 Complexmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Suzuki coupling activity of an aqueous phase Pd nanoparticle dispersion and a carbon nanotube/Pd nanoparticle composite

Sullivan¹,

Flanagan²,

Hain

2009

Catalysis Today

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“…It has been suggested that the small size of the metal nanoparticles leads to high surface/volume ratio and consequently high numbers of potential active sites available to the substrates, as a result of large enhancement in their catalytic activity while they are used as catalysts. [1,2] However, nanocatalysts are thermodynamically not stable due to their high excess surfaceenergy, therefore they have a tendency to aggregate unless they are stabilized. The methods for stabilizing nanoparticles mainly involve electrostatic stabilization, steric protection and coordination stabilization by the use of polymers, quaternary ammonium salts, dendrimers, surfactants, polyoxoanions or ligands etc.…”

Section: Introductionmentioning

confidence: 99%

Biphasic Hydrogenation of Olefins by Functionalized Ionic Liquid‐Stabilized Palladium Nanoparticles

Hou

et al. 2008

Adv Synth Catal

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Palladium nanoparticles in the size range of 5-6 nm were prepared conveniently by reducing palladium(II) with atmospheric pressure hydrogen and stabilized by 2,2'-dipyridylamine-functionalized imidazolium cations according to our approach. The efficient catalytic conversion of cyclohexene into cyclohexane by the functionalized ionic liquid-stabilized palladium nanoparticles has been performed under very mild hydrogen pressure (0.1 MPa) and at 35 8C. It was found that the concentration of palladium and the reaction temperature considerably affected the size and degree of aggregation of Pd nanoparticles in ionic liquid, which further changed the performance of the catalyst activity. The synthesized nanocatalysts can be recycled at least five times without any loss of the activity. Finally, the scope of substrates was also investigated. The excellent catalytic activity of the present system can be attributed to good stabilization and high dispersion of palladium nanoparticles.

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Metal Nanoparticles, Synthesis of

Schmid

2005

Encyclopedia of Inorganic Chemistry

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The successful synthesis of metal nanoparticles decisively depends on sufficient stabilisation by protecting materials. This can be reached either by electrostatic repulsion of charged species or by covering the surface atoms with polymers, surfactants, or especially ligand molecules binding to the particles via covalent bonds. Noble metals are in focus, since their salts or complexes can easily be reduced to the oxidation state 0 and the sensitivity towards oxygen is reduced or even avoided like in the case of gold. Nevertheless, nanoparticles of less noble metals can be prepared. Above all, there is an increasing need to get monodispersed particles, since their properties depend on size and shape. There exist so‐called physical methods to generate metal atoms from bulk metals that are then allowed to coalesce to nanoparticles. High temperatures or laser ablations are examples. Chemically based procedures use in any case stabilizing agencies. Among numerous methods, salt reduction dominates. Thermal decomposition of appropriate precursor complexes and soft ligand removal from organometallics have become known as alternative routes. Photolytic and radiolytic techniques exist, but do not play important roles. The synthesis of magnetic metal nanoparticles is of increasing interest with respect to applications. The syntheses mainly follow recipes known from noble metals. Fe, Co, Ni as well as magnetic bimetallic alloy‐like nanoparticles are available. The magnetic characteristics of nanoparticles again depend decisively on size, structure, and shape, even more than in case of the nonmagnetic species. Therefore, synthetic procedures resulting in uniform particles are of great importance.

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Giant palladium clusters as catalysts of oxidative reactions of olefins and alcohols

Cited by 188 publications

References 14 publications

Suzuki coupling activity of an aqueous phase Pd nanoparticle dispersion and a carbon nanotube/Pd nanoparticle composite

Suzuki coupling activity of an aqueous phase Pd nanoparticle dispersion and a carbon nanotube/Pd nanoparticle composite

Biphasic Hydrogenation of Olefins by Functionalized Ionic Liquid‐Stabilized Palladium Nanoparticles

Metal Nanoparticles, Synthesis of

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