Synthesis of N,N'-alkylidene bisamides and Suzuki-Miyaura coupling reaction derivatives with Pd organometallic catalyst anchored to channels of mesoporous silica MCM-41

At first, an organometallic catalyst namely, Pd-DPyE@MCM-41@MNP was prepared through magnetic (Fe3O4) nanoparticles-doped into channels of mesoporous silica MCM-41 and then, anchoring a novel complex composed of di(4-pyridyl)ethylene and palladium on the inner surface of the support. This immobilized catalyst was successfully identified via VSM, ICP-OES, TEM, FTIR, TGA, SEM, BET, XRD, EDX and elemental mapping analyses. After that, it was used as a versatile, heterogeneous, and magnetically reproducible catalyst in the generation of N,N'-alkylidene bisamides (1a-13a, 8-20 min, 90-98%, 50 °C, solvent-free) and Suzuki-Miyaura coupling (SMC) reaction derivatives (1b-26b, 10-140 min, 86-98%, 60 °C, PEG-400). The VSM plot of Pd-DPyE@MCM-41@MNP displays that this nanocatalyst can be easily recycled by applying an external magnetic field. In both synthetic paths, this nanocatalyst was reused at least seven times without palladium leaching and significantly reducing its catalytic performance. Also, stability and heterogeneous nature of catalyst were approved via ICP-OES technique and hot filtration test.

Antifungal activity of Fe3O4@SiO2/Schiff-base/Cu(II) magnetic nanoparticles against pathogenic Candida species

The antifungal efficacy and cytotoxicity of a novel nano-antifungal agent, the Fe3O4@SiO2/Schiff-base complex of Cu(II) magnetic nanoparticles (MNPs), have been assessed for targeting drug-resistant Candida species. Due to the rising issue of fungal infections, especially candidiasis, and resistance to traditional antifungals, there is an urgent need for new therapeutic strategies. Utilizing Schiff-base ligands known for their broad-spectrum antimicrobial activity, the Fe3O4@SiO2/Schiff-base/Cu(II) MNPs have been synthesized. The Fe3O4@SiO2/Schiff-base/Cu(II) MNPs was characterized by Fourier Transform-Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Energy-dispersive X-ray (EDX), Vibrating Sample Magnetometer (VSM), and Thermogravimetric analysis (TGA), demonstrating successful synthesis. The antifungal potential was evaluated against six Candida species (C. dubliniensis, C. krusei, C. tropicalis, C. parapsilosis, C. glabrata, and C. albicans) using the broth microdilution method. The results indicated strong antifungal activity in the range of 8-64 μg/mL with the lowest MIC (8 μg/mL) observed against C. parapsilosis. The result showed the MIC of 32 μg/mL against C. albicans as the most common infection source. The antifungal mechanism is likely due to the disruption of the fungal cell wall and membrane, along with increased reactive oxygen species (ROS) generation leading to cell death. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay for cytotoxicity on mouse L929 fibroblastic cells suggested low toxicity and even enhanced cell proliferation at certain concentrations. This study demonstrates the promise of Fe3O4@SiO2/Schiff-base/Cu(II) MNPs as a potent antifungal agent with potential applications in the treatment of life-threatening fungal infections, healthcare-associated infections, and beyond.

Green synthesis of quinazoline derivatives using a novel recyclable nano-catalyst of magnetic modified graphene oxide supported with copper

A new magnetic nano-catalyst system based on graphene oxide was designed and manufactured (GO@Fe3O4@3-chloropropyltrimethoxysilane@(Z)-N'-(2-hydroxybenzylidene)-4-(pyridin-4-yl)benzohydrazide@Cu(II)), and it was checked and confirmed by various analyzes such as FTIR, XRD, EDX, MAPPING, TGA/DSC, VSM and FESEM. This nano-catalyst was used in the three-component one-pot synthesis of quinazoline derivatives. The products were obtained using this efficient catalyst with high efficiency in short time and solvent-free conditions. Easy separation and acceptable recyclability are other advantages of this new nano-catalyst. Also, the catalyst can be recycled 4 times without a significant change in its efficiency.

Synthesis of palladium nanoparticles stabilized on Schiff base-modified ZnO particles as a nanoscale catalyst for the phosphine-free Heck coupling reaction and 4-nitrophenol reduction

Recently, the development of heterogeneous nanocatalytic systems using solid supports has been gaining importance due to some advantages such as easy handling, high thermal stability, high efficiency, reusability, and so on. Therefore, the design of catalyst supports for the preparation of stable heterogeneous catalytic systems is of great importance. In this work, Schiff base-modified ZnO particles have been developed (ZnO-Scb) as a novel support. A heterogeneous nanocatalyst system has then been prepared by immobilizing palladium nanoparticles (Pd NPs) on the ZnO-Scb surface as the support. The resulting palladium nanocatalyst (Pd-ZnO-Scb) structure has been characterized by different analytical techniques (FT-IR, XRD, TEM, FE-SEM, elemental mapping and EDS) and used to catalyze the Heck coupling reactions and 4-nitrophenol (4-NP) reduction. Test results revealed that Pd-ZnO-Scb could effectively couple various aryl halides with styrene in yields of up to 98% in short reaction times. Pd-ZnO-Scb was also efficiently used in the complete 4-NP reduction within 135 s at room temperature. Additionally, it was found that Pd-ZnO-Scb was more effective than other reported catalysts in the Heck coupling reaction. Moreover, the recycling tests indicated that Pd-ZnO-Scb could be easily isolated from the reaction medium and reused in seven consecutive catalytic runs while retaining its nanostructure.

β-Cyclodextrin-Functionalized Fe3O4-Supported Pd-Nanocatalyst for the Reduction of Nitroarenes in Water at Mild Conditions

In this study, a novel heterogeneous catalyst (Fe₃O₄@β-CD@Pd) has been developed by the deposition of palladium nanoparticles on the β-cyclodextrin-functionalized surface of magnetic Fe₃O₄. The catalyst was prepared by a simple chemical co-precipitation method and characterized extensively by using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-optical emission spectrometry (ICP-OES) analyses. Herein, the applicability of the prepared material was evaluated for the catalytic reduction of environmentally toxic nitroarenes to the corresponding anilines. The catalyst Fe₃O₄@β-CD@Pd showed excellent efficiency for the reduction of nitroarenes in water under mild conditions. A low catalyst loading of 0.3 mol % Pd is found to be efficient for reducing nitroarenes in excellent to good (99-95%) yields along with high TON values (up to 330). Nevertheless, the catalyst was recycled and reused up to the 5th cycle of reduction of nitroarene without any loss of significant catalytic activity.

Fe3O4/SiO2 decorated trimesic acid-melamine nanocomposite: a reusable supramolecular organocatalyst for efficient multicomponent synthesis of imidazole derivatives

This article describes supramolecular Fe3O4/SiO2 decorated trimesic acid-melamine (Fe3O4/SiO2-TMA-Me) nanocomposite that can be prepared with features that combine properties of different materials to fabricate a structurally unique hybrid material. In particular, we have focused on design, synthesis and evaluation a heterogeneous magnetic organocatalyst containing acidic functional-groups for the synthesis of biologically important imidazole derivatives in good to excellent yields. The introduced Fe3O4/SiO2-TMA-Me nanomaterial was characterized by different techniques such as FTIR, XRD, EDX, FESEM, TEM, TGA and DTA. As a noteworthy point, the magnetic catalytic system can be recycled and reused for more than seven consecutive runs while its high catalytic activity remains under the optimized conditions.

Nano-[Fe3O4@SiO2/N-propyl-1-(thiophen-2-yl)ethanimine][ZnCl2] as a nano magnetite Schiff base complex and heterogeneous catalyst for the synthesis of pyrimido[4,5-b]quinolones

Nano-[Fe₃O₄@SiO₂/N-propyl-1-(thiophen-2-yl)ethanimine][ZnCl₂] as a nano magnetite Schiff base complex was designed and fully characterized by various analyses such as Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric analysis (DTA), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and transmission electron micrographs (TEM). The presented nano magnetite Schiff base complex was used as a heterogeneous catalyst for the synthesis of pyrimido[4,5-b]quinolones by the reaction of aryl aldehyde, dimedone and 6-amino-1,3-dimethyluracil in EtOH : H₂O (7 : 3) as a solvent at 60 °C.

Nano-[Fe₃O₄@SiO₂/N-propyl-1-(thiophen-2-yl)ethanimine][ZnCl₂] as a nano magnetite Schiff base complex was designed and successfully tested for the synthesis of pyrimido[4,5-b]quinolones.

Synthesis of rare-earth metal complexes with a morpholine-functionalized β-diketiminato ligand and their catalytic activities towards C–O and C–N bond formation

Unusual tridentate β-diketiminato rare-earth metal chlorides LRECl(µ-Cl)2Li(THF)2 (RE = Y (1a), Yb (1b), Lu (1c); L = MeC(NDipp)CHC(Me)N(CH2)2NC4H8O; Dipp = 2,6-iPr2C6H3) and the corresponding dialkyl complexes LRE(CH2SiMe3)2 (RE = Y...

Ag2CO3 containing magnetic nanocomposite as a powerful and recoverable catalyst for Knoevenagel condensation

In this paper, the synthesis, characterization and catalytic application of a novel magnetic silica-supported Ag2CO3 (MS/Ag2CO3) with core-shell structure are developed. The MS/Ag2CO3 nanocomposite was prepared through chemical modification of magnetic MS nanoparticles with AgNO3 under alkaline conditions. The structure, chemical composition and magnetic properties of MS/Ag2CO3 were investigated by using VSM, PXRD, FT-IR, EDX and SEM techniques. The MS/Ag2CO3 nanocomposite was used as an effective catalyst for the Knoevenagel condensation under solvent-free conditions at 60 °C in an ultrasonic bath. The recovery and leaching tests were performed to study the nature of the MS/Ag2CO3 catalyst under applied conditions.

Green Synthesis of New Category of Pyrano[3,2-c]Chromene-Diones Catalyzed by Nanocomposite as Fe3O4@SiO2-Propyl Covalented Dapsone-Copper Complex

Nanomagnetic dapsone-Cu supported on the silica-coated Fe3O4 (Fe3O4@SiO2-pr@dapsone-Cu) nanocomposite was synthesized and characterized by Fourier transform infrared (FT-IR), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), zeta potential, vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). This newly synthesized nanocomposite was chosen to act as a green, efficient, and recyclable Lewis acid for the multicomponent synthesis of new derivatives of pyrano[3,2-c]chromene-diones through the reaction of aromatic aldehydes, indandione, and 4-hydroxycoumarin in water. All of the synthesized compounds are new and are recognized by FT-IR, NMR, and elemental analysis; this avenue is new and has advantages such as short reaction times, high productivity, economical synthesis, and use of green solvent, H2O, as a medium. The catalyst is magnetically recoverable and can be used after six runs without a decrease in the efficiency.

Nickel(II) Nanoparticles Immobilized on EDTA-Modified Fe3O4@SiO2 Nanospheres as Efficient and Recyclable Catalysts for Ligand-Free Suzuki-Miyaura Coupling of Aryl Carbamates and Sulfamates

A highly efficient and air-, thermal-, and moisture-stable nickel-based catalyst with excellent magnetic properties supported on silica-coated magnetic Fe₃O₄ nanoparticles was successfully synthesized. It was well characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, thermogravimetric analysis, dynamic light scattering (DLS), X-ray photoelectron spectroscopy, vibration sample magnetometry, energy-dispersive X-ray analysis, inductively coupled plasma analysis, and nitrogen adsorption-desorption isotherm analysis. The Suzuki-Miyaura coupling reaction between aryl carbamates and/or sulfamates with arylboronic acids was selected to demonstrate the catalytic activity and efficiency of the as-prepared magnetic nanocatalyst. Using the mentioned heterogeneous nanocatalyst in such reactions generated corresponding products in good to excellent yields in which the catalyst could easily be recovered from the reaction mixture with an external magnetic field to reuse directly for the next several cycles without significant loss of its activity.

N-Arylation of (hetero)arylamines using aryl sulfamates and carbamates via C–O bond activation enabled by a reusable and durable nickel(0) catalyst

An effective and general aryl amination protocol has been developed using a magnetically recoverable Ni(0) based nanocatalyst.

Carbon dioxide utilization in the efficient synthesis of carbamates by deep eutectic solvents (DES) as green and attractive solvent/catalyst systems

Deep eutectic solvents as a green solvent/catalyst system for directly synthesizing carbamates from amines, CO₂ and alkyl halides.