Immobilized copper-layered nickel ferrite on acid-activated montmorillonite, [(NiFe₂O₄@Cu)(H⁺-Mont)], as a superior magnetic nanocatalyst for the green synthesis of xanthene derivatives

Abstract

In this study, the immobilization of copper-layered nickel ferrite on the surface and in the cavities of acidactivated montmorillonite (H + -Mont) was investigated. In this context, magnetic nanoparticles (MNPs) of NiFe 2 O 4 as the prime magnetic cores were prepared. Next, through the reduction of Cu 2+ ions with sodium borohydride, the nanoparticles of Cu 0 were immobilized on the nanocore-surface of NiFe 2 O 4 , and the constituent NiFe 2 O 4 @Cu MNPs were obtained. Moreover, through the activation of montmorillonite K10 (Mont K10) with HCl (4 M) under controlled conditions, the H + -Mont constituent was prepared. The nanostructured NiFe 2 O 4 @Cu was then intercalated within the interlayers and on the external surface of the H + -Mont constituent to afford the novel magnetic nanocomposite (NiFe 2 O 4 @Cu)(H + -Mont). The prepared clay nanocomposite was characterized using FTIR spectroscopy, SEM, EDX, XRD, VSM and BET analyses. The obtained results showed that through acid-activation, the stacked-sheet structure of Mont K10 was exfoliated to tiny segments, leading to a significant increase in the surface area and total pore volume of the H + -Mont constituent as compared to those of montmorillonite alone. SEM analysis also exhibited that the dispersion of NiFe 2 O 4 @Cu MNPs in the interlayers and on the external surface of acid-activated montmorillonite was carried out successfully, and the nanoparticle sizes were distributed in the range of 15-25 nm. The BET surface analysis also indicated that through the immobilization of NiFe 2 O 4 @Cu MNPs, the surface area and total pore volume of the H + -Mont system were decreased. The catalytic activity of (NiFe 2 O 4 @Cu)(H + -Mont) was further studied towards the synthesis of substituted 13-aryl-5H-dibenzo [b,i]xanthene-5,7,12,14(13H) tetraones 3(a-k) and 3,3,6,6-tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H) diones 5(a-k) via the pseudo-one-pot three-component cyclocondensation of 2-hydroxy-1,4-naphthoquinone (Lawsone)/ dimedone and aromatic aldehydes in a mixture of H 2 O-EtOH (1 : 1 mL) as a green solvent at 80-90 C.The (NiFe 2 O 4 @Cu)(H + -Mont) MNPs can be easily separated from the reaction mixture by an external magnetic field and reused for seven consecutive cycles without significant loss of catalytic activity.

BF3@K10: An Efficient Heterogeneous Montmorillonite Catalyst for the Halogenation of N-Heterocycles

“…In addition, the bands at 528 and 467 cm -1 correspond to the deformation vibrations of Si-O-Al and Si-O-Si, respective-ly. 20 A comparison of the IR spectra of the K10 and BF 3 @K10 materials reveals that, owing to the impregnation of boron trifluoride into MMT, the position of the strong band at 1048 cm -1 (stretching vibration of Si-O in tetrahedral sites) has been shifted to 1094 cm -1 .…”

Immobilized Cu(0) nanoparticles on montmorillonite-modified with benzalkonium chloride (MMT-BAC@Cu(0)): as an eco-friendly and proficient heterogeneous nano-catalyst for green synthesis of 5-substituted 1H-tetrazoles

“…Properties such as cation exchange capacity, high surface reactivity, high adsorption capacity, biocompatibility, uses in cosmetics, catalysis, pharmacy, medicine, and sensors can be named as some MMT clay applications. 4,5 Because of their adjustable Brønsted and Lewis acidities, clays are utilized as effective catalysts for various organic transformations. 6,7 Many natural remedies and medicines such as atropine, codeine, morphine, diazepam, metronidazole, azidothymidine, and methotrexate are known as heterocyclic compounds.…”

Synthesis of GO and rGO@Fe3O4@Ni as remarkable nanocatalyst systems for solvent‐free and chemoselective coupling reactions of dimedone with aromatic aldehydes

“…In line with the outlined strategies and to continue our research program that aims to synthesize nanocatalysts as promoters of organic syntheses, [ 60–66 ] herein, we synthesize and characterize GO and rGO@Fe 3 O 4 @Ni nanosystems and investigate their applicability as chemoselective catalysts in multicomponent coupling reactions (MCRs) of dimedone with aromatic aldehydes to afford bisdimedones or xanthenediones in solvent‐free conditions (90°C) (Scheme 2).…”