N‐Heterocyclic Carbene‐Protected Ag Nanoparticles Immobilized on Polyacrylonitrile Fiber as Efficient Catalysts for a Three‐Component Coupling Reaction

Abstract

Metal nanoparticles (NPs) are routinely stabilized by the introduction of capping agents or their distribution on supports. In this context, we report the preparation and characterization of N-heterocyclic carbene (NHC)-stabilized silver NPs supported on polyacrylonitrile fiber (PANF). As a result, Ag loadings of up to 8 % and particle sizes of 11.0±3.2 nm were achieved. This novel nanocomposite catalyst demonstrated high activity in addition to excellent stability and reusability in the three-component reaction between alkynes, haloalkanes, and amines. In this system, the AgNPs were stabilized by both a support effect and a ligand effect. The unique NHC-protected AgNP structure and the PANF support provide a synergistic effect in the deprotonation of C -H bonds, with turnover numbers of up to 3500. This catalyst was successfully recycled over eight runs without any significant loss in activity, and with no significant aggregation of the AgNPs. Moreover, implementation of a flow system with PANF-NHC@Ag as catalyst leads to an efficient productivity of 57 mmol h .

Highly Selective and Sensitive Detection of Hydrogen Sulfide by the Diffraction Peak of Periodic Au Nanoparticle Array with Silver Coating

“…Figure b presents the Ag 3d spectrum energy region of the Au nanosphere array with silver coating. The peaks at 374.02 and 368.02 eV were ascribed to the metallic Ag 3d 3/2 and Ag 3d 5/2 , respectively. − Figure d shows the Ag 3d XPS spectrum of the Au nanosphere array with silver coating after detecting 2 μM H 2 S. The two peaks shifted to higher binding energies, which were at 374.08 and 368.08 eV. Apart from metallic Ag, the peaks at 374.10 and 368.10 eV also existed, which were attributed to the Ag + of Ag 2 S .…”

Monomeric and Polymeric Mesoionic N-Heterocyclic Carbene-Tethered Silver Nanoparticles: Synthesis, Stability, and Catalytic Activity

“…Furthermore, as shown in Figure 2e, the XRD profile of both AgNP1 and AgNP2 showed signals at 38.2, 44.4, 64.6, and 77.6°, which correspond to the (111), ( 200), (220), and (311) planes of the fcc lattice of Ag, respectively, thus further proving the crystallinity of their core. The resulting values perfectly agree with prior literature reports of NHC-functionalized AgNPs 43,45 and demonstrate the successful reduction of molecular species to AgNPs. In addition, TGA was used to determine the composition of the nanoparticles.…”

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

“…The latter reacts with phenylacetylene adsorbed on the surface of the catalyst to give propargylamines. As evident from the literature reports, the mechanism for AuNP-catalyzed AHA coupling is completely different from than that of AgNPs (Scheme 9), 56 where DCM rst reacts with amine to form an iminium ion, which then interacts with the metal-phenyl acetylide complex to form propargylamines.…”