Cyclodextrin‐Grafted Silica‐Supported Pd Nanoparticles: An Efficient and Versatile Catalyst for Ligand‐Free C−C Coupling and Hydrogenation

Abstract

Silica is an extremely versatile support, which is capable of hosting metal nanoparticles (NPs) and enhancing their stability and reactivity. In this study, a novel cyclodextrin/silica support for Pd NPs, which we have denoted Pd/Si‐CD, has been prepared. The highly efficient and homogeneous impregnation of small palladium nanoparticles on this support has been carried out under conventional conditions, and ultrasound irradiation has been shown to have a beneficial effect on catalyst preparation. The catalyst exhibited excellent activity in ligand‐free C−C Suzuki and Heck couplings with a large number of aryl iodide and bromides, in which microwave irradiation use cuts down reaction time. Pd/Si‐CD have shown high activity and selectivity in the hydrogenation reaction, and the semihydrogenation of phenyl acetylene was also studied with excellent results.

Sonochemically-Promoted Preparation of Silica-Anchored Cyclodextrin Derivatives for Efficient Copper Catalysis

“…On the basis of our experience with covalently-functionalized silica [54,55], the modification of silica surfaces via the grafting of organic compounds can lead to improve catalytic activity and may increase sorption capacity. With the aim of obtaining different silica-support-grafted β-CDs for Cu(II) species using a short and reliable synthetic protocol, two different routes were compared.…”

Eco-Friendly Physical Activation Methods for Suzuki–Miyaura Reactions

“…Martina et al have reported [102] the synthesis of a novel cyclodextrin/silica support to host Pd nanoparticles with enhanced stability and reactivity, according to Scheme 47. The authors ascribed the formation of homogeneously dispersed Pd nanoparticles of small size to the presence of a coordinating group.…”

“…Silica is a remarkably versatile support and one that is able to host metal nanoparticles (NPs) and improve their reactivity and stability. Martina et al [102], have recently prepared a novel cyclodextrin/silica support for Pd NPs (Pd/Si-CD) (Scheme 45). Cyclodextrin (CD) grafting into an inorganic silica framework provided a hybrid organic/inorganic material suitable for further metal impregnation.…”

Biogenic synthesis of palladium nanoparticles using Boswellia sarrata and their applications in cross‐coupling reactions

“…However, in the last few years, the importance of palladium‐based heterogeneous catalytic systems has received significant attention because of their facile recovery and reusability. Precedently, carbon, [ 7 ] magnetic materials, [ 8 ] silica, [ 9 ] hydroxyapatite, [ 10 ] zeolites, [ 11 ] Pd/DNA, [ 12,13 ] metal organic frameworks (MOFs), [ 14 ] organic polymers, [ 15 ] clays, [ 16 ] and bio‐supports [ 17,18 ] have been employed for as support for this purpose. In the recent years, palladium nanoparticles (PdNPs) have garnered tremendous attention in heterogeneous catalysis due to their excellent catalytic activity.…”