Stereoselective reduction of disubstituted aromatics on colloidal rhodium

Nasar, K.; Fache, Fabienne; Lemaire, Marc; Beziat, J.C.; Бессон, М.; Gallezot, P.

doi:10.1016/0304-5102(93)e0199-q

Cited by 80 publications

(44 citation statements)

References 12 publications

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“…The results show that the counter-ion (X À stabiliser) significantly influences the catalytic activities. The rhodium suspensions stabilised by HEA16Cl, HEA16BF 4 and HEA16Ms give analogous activities during the first run. The reaction time varies between 3.6 and 4.3 h. Nevertheless, the CH 3 SO 3 anion gives an emulsion generating a small metal loss.…”

Section: Hea16clmentioning

confidence: 84%

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Arene Hydrogenation with a Stabilised Aqueous Rhodium(0) Suspension: A Major Effect of the Surfactant Counter‐Anion

2003

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A reduced aqueous colloidal suspension of rhodium shows an efficient activity in the catalytic hydrogenation of various benzene derivatives under biphasic conditions at room temperature and under atmospheric hydrogen pressure. The rhodium nanoparticles in the size range of 2 ± 2.5 nm have been synthesised by reducing RhCl 3 ¥ 3 H 2 O with sodium borohydride and were stabilised by highly watersoluble N,N-dimethyl-N-cetyl-N-(2-hydroxyethyl)ammonium salts (HEA16X, X Br, Cl, I, CH 3 SO 3 , BF 4 ). The major influence of the counter-ion of these surfactants on catalytic activity and recycling is described. The best results have been obtained with chloride ammonium salts HEA16Cl.

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Section: Hea16clmentioning

confidence: 84%

“…In numerous cases, the reaction is twice as active when the Rh(0) nanoparticles are stabilised by HEA16Cl than the other standard surfactants HEA16Br, Ms or BF 4 .…”

Section: Full Papersmentioning

confidence: 99%

Arene Hydrogenation with a Stabilised Aqueous Rhodium(0) Suspension: A Major Effect of the Surfactant Counter‐Anion

2003

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“…[58][59][60][61][62][63][64][65][66][67][68] Despite the impressive progress in catalysis, however, only a few NP systems were found to be efficient in asymmetric catalysis till today. [75,86,[95][96][97][98][99][100][101][102][103] The most relevant systems involve Pt and Pd NPs stabilized by cinchonidine, in the hydrogenation of pyruvate derivatives with ee up to 95-98 %. [95, 97-100, 104, 105] Gold catalysis has become a hot topic and many published examples have demonstrated benefits of gold catalysts such as higher activity, milder conditions, and higher selectivity and enantioselectivity.…”

Section: Potential Applicationsmentioning

confidence: 99%

Chiral Gold Nanoparticles

2009

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Monolayer-protected gold nanoparticles have many appealing physical and chemical properties such as quantum size effects, surface plasmon resonance, and catalytic activity. These hybrid organic-inorganic nanomaterials have promising potential applications as building blocks for nanotechnology, as catalysts, and as sensors. Recently, the chirality of these materials has attracted attention, and application to chiral technologies is an interesting perspective. This minireview deals with the preparation of chiral gold nanoparticles and their chiroptical properties. On the basis of the latter, together with predictions from quantum chemical calculations, we discuss different models that were put forward in the past to rationalize the observed optical activity in metal-based electronic transitions. We furthermore critically discuss these models in view of recent results on the structure determination of some gold clusters as well as ligand-exchange experiments examined by circular dichroism spectroscopy. It is also demonstrated that vibrational circular dichroism can be used to determine the structure of a chiral adsorbate and the way it interacts with the metal. Finally, possible applications of these new chiral materials are discussed.

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“…The first example of enantioselective catalysis by NPs was reported in 1994 by Nasar et al [169] They showed that Rh NPs catalysed hydrogenations of disubstituted aromatic rings induced by a chiral amine, R-dioctylcyclohexyl-1-ethylamine as ligand. Bönnemann and co-workers reported the efficiently catalysed hydrogenation of ethyl pyruvate by Pt or Pd NPs with cinchonidine ligands (up to 95-98% ee, see Fig.…”

Section: Ligand-stabilized Npsmentioning

confidence: 99%

Transition‐metal nanoparticles: synthesis, stability and the leaching issue

Pachón

Rothenberg

2008

Applied Organom Chemis

418

202

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This perspective examines the state-of-the-art of catalysis by metal nanoparticles. We outline various methods for preparing metal nanoparticle suspensions, and highlight the role of the stabilizers and the stabilizing principles. Subsequently, we examine some catalytic applications of homometallic and bimetallic nanoparticle suspensions in a variety of reactions. The cases are divided according to the stabilizing agent: polymers, dendrimers, ionic liquids, surfactants, micelles and micoremulsions, ligands and solid supports. We explain the importance of atom/ion leaching (all too frequent in nanoparticle catalysis, especially for the catalytically active group VIII metals) and consider ways of minimizing it. The future perspectives of nanoparticles as catalysts are discussed.

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Stereoselective reduction of disubstituted aromatics on colloidal rhodium

Cited by 80 publications

References 12 publications

Arene Hydrogenation with a Stabilised Aqueous Rhodium(0) Suspension: A Major Effect of the Surfactant Counter‐Anion

Arene Hydrogenation with a Stabilised Aqueous Rhodium(0) Suspension: A Major Effect of the Surfactant Counter‐Anion

Chiral Gold Nanoparticles

Transition‐metal nanoparticles: synthesis, stability and the leaching issue

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