Palladium(0) Nanoparticles Embedded in Core–shell Nanogels as Recoverable Catalysts for the Mizoroki–Heck Reaction

Abstract

Core–shell nanogels are attractive stabilizers and supports for catalytically active metallic nanoparticles. Herein, we present the synthesis and the characterization of a nanostructured well‐defined core–shell nanogel with the ability to stabilize Pd0 nanoparticles in its core. This hybrid nanogel displays a remarkable stability in both the solid state and in solution. This feature allowed its successful application as a catalyst for the Mizoroki–Heck reaction between n‐butyl acrylate and a series of bromo‐ and iodoarenes. The yields spanned from good to excellent, and catalyst recycling could be achieved up to three times without a significant activity loss. Three‐phase tests indicated that the hybrid nanogel acts as a Pd0 nanoreservoir. The catalysis proceeds in a quasihomogeneous fashion as part of the catalytic activity occurs outside the nanogel, which explains the observed limited recyclability.

Stabilization of Nanoparticles Produced by Hydrogenation of Palladium–N-Heterocyclic Carbene Complexes on the Surface of Graphene and Implications in Catalysis

“…Functionalization of metal NPs with organic ligands avoids aggregation and controls the particle size and distribution. 19−21 These properties markedly regulate the catalytic applications of metal NPs. However, even the functionalized NPs suffer dynamic changes at the surface during the catalytic reactions, and single atoms and/or metal clusters are released to the reaction media forming new species.…”

RAFT‐vermittelte polymerisationsinduzierte Selbstorganisation (PISA)

“…[267][268][269][270] Metallische Pd 0 -Nanopartikel sind ebenfalls eingearbeitet worden, zum Beispiel in durch PISA erhaltene Nanogele.D iese zeigten eine bemerkenswerte Stabilitäti mf esten Zustand und in Lçsung -e ine Eigenschaft, die den erfolgreichen Einsatz als Katalysator für die Mizoroki-Heck-Reaktion zwischen n-Butylacrylat und einer Reihe von Brom-und Iodarenen ermçglichte. [271] Zusätzlich zu den oben genannten Beispielen wurde bereits eine große Vielfalt von Metall-Hybridnanokatalysatoren (die meisten der eingearbeiteten Metallpartikel) mittels PISA synthetisiert, aber ihre detaillierte Beschreibung liegt außerhalb des Rahmens dieses Aufsatzes.…”

Pd–Co Nanoparticles Supported on Calcined Mg–Fe Hydrotalcites for the Suzuki–Miyaura Reaction in Water with High Turnover Numbers

“…By contrast, a heterogeneous Pd catalyst could obviate these limitations and open up a valuable alternative technology in such processes [13][14][15][16][17]. In recent years, palladium nanoparticles (NPs) supported by various substrates, such as active carbon materials [18,19], silica [20][21][22], polymers [23,24], inorganic mineral [25,26], metal oxides [27][28][29], and covalent organic frameworks (COFs) [30,31] have been designed and applied for the Suzuki-Miyaura reaction. However, these methods usually require high catalyst loadings (from 0.021 to 1 mol % Pd), high-reaction temperatures, and long reaction times.…”