Dendritic Core–Multishell Polymer Templates for the Synthesis of Pt Nanoparticle‐Loaded Porous Silica and their Application as Catalysts for the Enantioselective Hydrogenation of Ethyl Pyruvate

Abstract

Cores célèbre: The synthesis of metal nanoparticle‐loaded mesoporous silica and their application to enantioselective reactions are described. Dendritic core–multishell polymers are used as stabilizers for Pt nanoparticles and as templates for the synthesis of mesoporous silica. The catalysts can be recycled for at least nine cycles with high enantiomeric excesses and full conversion in the reduction of ethyl pyruvate.

Core–shell nanoparticles: synthesis and applications in catalysis and electrocatalysis

“…Then, using a controlled etching technique (by treating the sample with strong base at elevated temperature), allowed formation of a thin shell surrounding the Au-NP core. 250 Mainly comprising ''organic'' materials, special types of coremultishell NPs have been introduced recently involving supramolecular dendritic assemblies, which have potential applications in drug/dye/metal ions delivery 251-257 as well as catalysis [258][259][260] etc. 12).…”

“…12). [258][259][260] 3.1.1.3.3. 244 The particle-size (and also shell thickness) was shown to be easily controllable and in good agreement with calculated values.…”

Pore Structure and Surface Acidity Effects of Ordered Mesoporous Supports on Enantioselective Hydrogenation of Ethyl Pyruvate

“…[25] The leaching stability of Pt nanoparticle-loaded porous silica was also confirmed by the investigations of Haag and coworkers. [13] The prepared samples consisted of comparable amounts of supported Pt on amorphous silica and had undergone the same metal loading and reduction procedure. Thus, an effect of the support on the electronic properties of Pt (metal-support interactions) can be excluded as an explanation for these changes.…”

“…[11] Very promising results for SBA-15-like materials as supports for the catalytically active Pt were published recently. [12,13] It is well accepted that a narrowly distributed Pt crystallite size in the range of 1.5-4.0 nm is beneficial. [3] However, the role of the chemical nature and of the texture of the support has been disputed.…”

Chiral metal nanoparticle-catalyzed asymmetric C–C bond formation reactions

“…37,38 Although the first Oritotype reaction was reported more than 30 years ago, this type of reaction is still being studied. [39][40][41][42][43] Recently, studies were carried out to improve the catalyst system [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] and to reveal its detailed mechanism. [62][63][64][65][66][67] It is generally accepted that the chemisorption layer, through the formation of individual 1 : 1 diastereomeric complexes from substrates and chiral modifiers, is the key to inducing chirality in this reaction.…”