Silica Microparticles Supported Gold and Copper Ferrite Nanoparticles: A Magnetically Recyclable Bimetallic Catalyst for Sonogashira Reaction

Abstract

Abstract:Novel silica supported gold and copper ferrite nanoparticles (NPs) have been synthesized, characterized and used as a separable dual catalyst in Sonogashira type reaction. These Au·CuFe2O4@Silica NPs show a high efficiency as catalyst in the alkynylation not only of aryl iodides but also aryl bromides. By using only 0.5 mol% loading and t-BuOK as base in N,Ndimethylacetamide as solvent, aryl iodides react at 115 ºC in 1 d, whereas for aryl bromides the cross-coupling takes place at 130 ºC in 2 d. The catalyst can be successfully recycled using an external magnet for four consecutive runs.

The CuFe2O4@SiO2@ZrO2/SO42−/Cu nanoparticles: an efficient magnetically recyclable multifunctional Lewis/Brønsted acid nanocatalyst for the ligand- and Pd-free Sonogashira cross-coupling reaction in water

“…4 More importantly, the presence of copper as a co-catalyst promotes the Glaser-type homo-coupling of terminal acetylenes to generate a by-product (Scheme 1); thus, various attempts have been developed to perform the reaction under copper-free and Pdfree conditions in a mild, safe, ecofriendly, and cost-effective manner; in this regard, one strategy is the use of cheaper and safer alternative transition metals including Ni, 5 Cu, 6 Fe, 7 and Co. 8 Among these, the potential of Cu for application in the C-N as well as C-C cross coupling reactions is well-known; 9 moreover, several achievements have been reported for the Cu-catalyzed Sonogashira reaction; the recent examples include the use of Cu 2 O/RGO, 10 Cu/ Mn bimetallic, 9 CuI/PPh 3 /K 2 CO 3 , 11 CuI/K 3 PO 4 /1,4-dioxane, 12 and Au$CuFe 2 O 4 @silica as catalysts for this reaction. 2 Recently, Sun and coworkers 13 have reported the application of a Cu-MOF derived from two-phase Cu/Cu 2 O-rGO as an efficient catalyst for the Sonogashira reaction.…”

Starch functionalized creatine for stabilization of gold nanoparticles: Efficient heterogeneous catalyst for the reduction of nitroarenes

“…6). The XPS spectrum in the Au 4f region showed an intense doublet at 83.6 and 87.4 eV confirming complete reduction of Au(III) to Au(0) (Figure 6a) [48]. Also, XPS analysis for the N 1s region confirmed the presence of nitrogen in the structure by appearing a peak centered at 400 eV (Figure 6b) [49,50].…”

Iron oxide modified with pyridyl‐triazole ligand for stabilization of gold nanoparticles: An efficient heterogeneous catalyst for A3 coupling reaction in water

“…X‐ray diffraction (XRD) analysis of the prepared catalyst showed the presence of Fe 3 O 4 NPs by screening Bragg's reflections at 2 θ = 30.18°, 35.5°, 43.4°, 53.5°, 57.2° and 62.8° corresponding to the (210), (311), (400), (422), (511) and (440) planes of Fe 3 O 4 NPs, respectively . Due to low loading weight of Au, peaks relating to metallic gold were weak and appeared at 2 θ = 38°, 44.2°, 65° and 78° (Figure ) …”

“…[111] Due to low loading weight of Au, peaks relating to metallic gold were weak and appeared at 2θ= 38°, 44.2°, 65°and 78° (Figure 7). [112,113] The X-ray photoelectron spectrum (XPS) of the Fe 2p region shows two main binding energy peaks corresponding to the electronic states of Fe 2p 3 (Figure 8a). [114][115][116] In the case of the XPS spectrum for the Au 4f region, a doublet peak at 83.9 and 87.5 eV corresponding to Au(0) was observed, comprising the only Au species in the material (Figure 8b).…”