Well-defined nanomagnetic nitrilotriacetic acid complex of Cu(ii) supported on silica-coated nanosized magnetite: a new highly efficient and magnetically separable catalyst for C-N bond formation

A nitrilotriacetic acid (NTA) complex of Cu(ii) supported on silica-coated nanosized magnetite Fe3O4@SiO2-Pr-DEA-[NTA-Cu(ii)]2 was prepared as a new well-defined magnetically separable nanomaterial and fully characterized via IR, XRD, FESEM, TEM, TGA, DLS, BET, VSM, solid-state UV-vis spectroscopy, EDX, ICP-OES, and FESEM-EDX map analyses. Thereafter, it was successfully applied as a new easily magnetically separable and reusable heterogeneous nanocatalyst for the Buchwald-Hartwig C-N bond formation reaction in DMF at 110 °C. Using this method, various kinds of nitrogen heterocycles, such as imidazoles, 2-methyl-1H-imidazole, benzimidazole, indole, and 10H-phenothiazine as well as aliphatic secondary amines such as piperidine, piperazine, morpholine, dimethylamine, and diethylamine, were reacted with aryl halide compounds, and the desired products were obtained with good to excellent yields. In all cases, the applied catalyst could be recovered easily and rapidly using an external magnet and reused 7 times without significant loss of catalytic activity.

Nickel ferrite decorated noble metal containing nitrogen-doped carbon nanotubes as potential magnetic separable catalyst for dinitrotoluene hydrogenation

The 2,4-toluenediamine (TDA) is one of the most important chemicals in the polyurethane industry, produced by the catalytic hydrogenation of 2,4-dinitrotoluene (DNT). The development of novel catalysts that can be easily recovered from the reaction mixture is of paramount importance. In our work, a NiFe2O4/N-BCNT supported magnetic catalyst was prepared by a modified coprecipitation method. The catalyst support alone also showed activity in the synthesis of TDA. Platinum nanoparticles were deposited on the catalyst support surface by a fast, relatively simple, and efficient sonochemical method, resulting in a readily applicable catalytically active system. The prepared catalyst exhibited high activity in hydrogenation tests, which was proved by the exceptionally high DNT conversion (100% for 120 min at 333 K) and TDA yield (99%). Furthermore, the magnetic catalyst can be easily recovered from the reaction medium by the action of an external magnetic field, which can greatly reduce catalyst loss during separation.

Transferrin Immobilized Graphene Oxide Nanocomposite for Targeted Cancer Chemodynamic Therapy via Increasing Intracellular Labile Fe2+ Concentration

Recently, different alternative regulated cell death (RCD) pathways, viz., necroptosis, pyroptosis, ferroptosis, cuproptosis etc., have been explored as important targets for the development of cancer medications in recent years, as these can change the immunogenicity of the tumor microenvironment (TME) and will finally lead to the inhibition of cancer progression and metastasis. Here, we report the development of transferrin immobilized graphene oxide (Tfn@GOAPTES) nanocomposite as a therapeutic strategy toward cancer cell killing. The electrostatic immobilization of Tfn on the GOAPTES surface was confirmed by different spectroscopy and microscopy techniques. The Tfn immobilization was found to be ∼74 ± 4%, whereas the stability of the protein on the GO surface suggested a robust nature of the nanocomposite. The MTT assay suggested that Tfn@GOAPTES exhibited cytotoxicity toward HeLa cells via increased lipid peroxidation and DNA damage. Western blot studies resulted in decreased expression of acetylation on lysine 40 of α-tubulin and increased expression of LC3a/b for Tfn@GOAPTES treated HeLa cells, suggesting autophagy to be the main cause of the cell death mechanism. Overall, we predict that the present approach can be used as a therapeutic strategy for cancer cell killing via selective induction of a high concentration of intracellular iron.

Synthesis, modifications, and applications of iron-based nanoparticles

Magnetic nanoparticles (MNPs) are appealing materials as assistant to resolve environmental pollution issues and as recyclable catalysts for the oxidative degradation of resistant contaminants. Moreover, they can significantly influence the advancement of medical applications for imaging, diagnostics, medication administration, and biosensing. On the other hand, due to unique features, excellent biocompatibility, high curie temperatures and low cytotoxicity of the Iron-based nanoparticles, they have received increasing attention in recent years. Using an external magnetic field, in which the ferrite magnetic nanoparticles (FMNPs) in the reaction mixtures can be easily removed, make them more efficient approach than the conventional method for separating the catalyst particles by centrifugation or filtration. Ferrite magnetic nanoparticles (FMNPs) provide various advantages in food processing, environmental issues, pharmaceutical industry, sample preparation, wastewater management, water purification, illness therapy, identification of disease, tissue engineering, and biosensor creation for healthcare monitoring. Modification of FMNPs with the proper functional groups and surface modification techniques play a significant role in boosting their capability. Due to flexibility of FMNPs in functionalization and synthesis, it is possible to make customized FMNPs that can be utilized in variety of applications. This review focuses on synthesis, modifications, and applications of Iron-based nanoparticles.

Chemical characterization and effect of Ziziphora clinopodioides green-synthesized silver nanoparticles on cytotoxicity, antioxidant, and antidiabetic activities in streptozotocin-induced hepatotoxicity in Wistar diabetic male rats

The present research studied the cytotoxicity, antioxidant, and antidiabetic activities of biogenically synthesized silver nanoparticles (AgNPs) using Ziziphora clinopodioides (Z. clinopodioides) as a green mediator. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) were employed to determine AgNPs. In the in vivo experiment, the model rats were categorized into different groups receiving 50, 100, 200, and 400 μg/kg of AgNPs and diabetic, positive, and normal groups (n = 10) using a random division. A single dose of streptozotocin (STZ) at 60 mg/kg was administered to induce diabetes and hepatotoxicity in rats. The administration of AgNPs was performed via intragastric administration for 25 days. On the final day, the levels of glucose and biochemical enzymes, namely aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine transaminase (ALT), and gamma-glutamyltransferase (GGT), were assessed in the serum. Following tissue processing, liver sections with a thickness of 5 μm were prepared. Later, the total volume of different liver components, such as hepatocytes, sinusoids, portal vein, central vein, hepatic arteries, and bile ducts, was measured. The portal vein and bile duct volumes did not vary significantly in groups treated by AgNPs. However, the volume of the central vein and hepatic arteries exhibited noticeable variations in groups treated by AgNPs. After administration of streptozotocin, the volume of hepatocytes and sinusoids increased significantly. However, treatment with a high dose of AgNPs significantly decreased the volume of hepatocytes and sinusoids. In diabetic rats, administering AgNPs reduced the fasting blood glucose levels compared to the model group. In addition, AgNPs decreased the elevated levels of AST and ALP enzymes in a manner that depended on the dosage of AgNPs used. This research demonstrates the hepatoprotective and antidiabetic properties of AgNPs, suggesting their potential implications as hepatoprotective and antidiabetic supplements to prevent diabetes.

Magnetic nanocomposite based on chitosan-gelatin hydrogel embedded with copper oxide nanoparticles: A novel and promising catalyst for the synthesis of polyhydroquinoline derivatives

Nanocatalysts are vital in several domains, such as chemical processes, energy generation, energy preservation, and environmental pollution mitigation. An experimental study was conducted at room temperature to evaluate the catalytic activity of the new gelatin-chitosan hydrogel/CuO/Fe3O4 nanocomposite in the asymmetric Hantzsch reaction. All components of the nanocomposite exhibit a synergistic effect as a Lewis acid, promote the reaction. Dimedone, ammonium acetate, ethyl acetoacetate, and other substituted aldehydes were used to synthesize diverse polyhydroquinoline derivatives. The nanocomposite exhibited exceptional efficacy (over 90 %) and durability (retaining 80 % of its original capacity after 5 cycles) as a catalyst in the one-pot asymmetric synthesis of polyhydroquinoline derivatives. Also, turnover numbers (TON) and turnover frequency (TOF) have been checked for catalyst (TON and TOF = 50,261 and 100,524 h-1) and products. The experiment demonstrated several benefits, such as exceptional product efficacy, rapid reaction time, functioning at ambient temperature without specific requirements, and effortless separation by the use of an external magnet after the reaction is finished. The results suggest the development of a magnetic nanocatalyst with exceptional performance. The composition of the Ge-CS hydrogel/CuO/Fe3O4 nanocomposite was thoroughly analyzed using several methods including FT-IR, XRD, FE-SEM, EDX, VSM, BET, and TGA. These analyses yielded useful information into the composition and characteristics of the nanocomposite, hence further enhancing the knowledge of its possible uses.

Microwave-Assisted Silanization of Magnetite Nanoparticles Pre-Synthesized by a 3D Microfluidic Platform

Magnetite nanoparticles (Fe3O4 NPs) are among the most investigated nanomaterials, being recognized for their biocompatibility, versatility, and strong magnetic properties. Given that their applicability depends on their dimensions, crystal morphology, and surface chemistry, Fe3O4 NPs must be synthesized in a controlled, simple, and reproducible manner. Since conventional methods often lack tight control over reaction parameters and produce materials with unreliable characteristics, increased scientific interest has been directed to microfluidic techniques. In this context, the present paper describes the development of an innovative 3D microfluidic platform suitable for synthesizing uniform Fe3O4 NPs with fine-tuned properties. On-chip co-precipitation was performed, followed by microwave-assisted silanization. The obtained nanoparticles were characterized from the compositional and microstructural perspectives by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, supplementary physicochemical investigations, such as Fourier Transform Infrared Spectroscopy (FT-IR), Kaiser Test, Ultraviolet-Visible (UV-Vis) Spectrophotometry, Dynamic Light Scattering (DLS), and Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) analyses, demonstrated the successful surface modification. Considering the positive results, the presented synthesis and functionalization method represents a fast, reliable, and effective alternative for producing tailored magnetic nanoparticles.

Functionalization of Fe3O4@SiO2 nanoparticles with Cu(i)-thiosemicarbazone complex as a robust and efficient heterogeneous nanocatalyst for N-arylation of N-heterocycles with aryl halides

In this research, the functionalized silica-coated magnetite nanoparticles with Cu(i)-thiosemicarbazone complex (Fe3O4@SiO2-[CuL]) has been designed and synthesized as a magnetically retrievable nanocatalyst. Different techniques were employed to characterize the structure of Fe3O4@SiO2-[CuL] comprising FT-IR, FE-SEM, TEM, DLS, XRD, EDX, TGA, AAS, and VSM analysis. The catalytic performance of Fe3O4@SiO2-[CuL] was perused in Ullmann-type N-arylation of nucleobases, xanthines, and other N-heterocycles with diverse aryl halides which acquired the desired N-aryl products in good to excellent yields. Fe3O4@SiO2-[CuL] is a thermal and chemical stable, easy to prepare and recyclable, inexpensive, and ecofriendly catalyst that needs no additional additive or ligand as promoters. This catalyst could be separated without difficulty by a simple magnet and reused for at least seven sequential runs without a significant decline in its catalytic performance.

Synthesis of Fe3O4@SiO2@Pr-NH2@DAP as a magnetic recyclable nano-catalyst for efficient synthesis of pyranothiazolopyrimidines and 4H-pyrans under solvent-free condition

In this research, we describe the synthesis of silica-coated nano-Fe3O4 particles, which were successfully modified by diaminopyrimidine, and their physicochemical properties were characterized using FT-IR, XRD, TEM, FE-SEM, EDX, EDX-mapping, and TGA. The catalytic activity of this novel nano-catalyst was evaluated by three-component reactions for the preparation of pyranothiazolopyrimidines and 4H-pyrans under solvent-free conditions. Recyclability of the catalyst up to six consecutive rounds, atom economy, high yield and purity of desired products, and easy work-up method are some of the exciting features of this system that make it more favorable from a green chemistry point of view.

Recent advances in the application of magnetic nanocatalysts in multicomponent reactions

Recently, the preparation and applications of magnetic nanostructures have attracted increasing attention in nanocatalysis studies, and magnetic nanoparticle (MNP) functionalized catalysts have been applied in important reactions such as Suzuki-Miyaura and Heck couplings. The modified nanocomposites demonstrate significant catalytic efficiency and excellent benefits in the context of catalyst recovery methods. This review discusses the recent modified magnetic nanocomposites in the field of catalytic applications along with the synthetic processes that are usually employed.

Hard-Soft Core-Shell Architecture Formation from Cubic Cobalt Ferrite Nanoparticles

Cubic bi-magnetic hard-soft core-shell nanoarchitectures were prepared starting from cobalt ferrite nanoparticles, prevalently with cubic shape, as seeds to grow a manganese ferrite shell. The combined use of direct (nanoscale chemical mapping via STEM-EDX) and indirect (DC magnetometry) tools was adopted to verify the formation of the heterostructures at the nanoscale and bulk level, respectively. The results showed the obtainment of core-shell NPs (CoFe₂O₄@MnFe₂O₄) with a thin shell (heterogenous nucleation). In addition, manganese ferrite was found to homogeneously nucleate to form a secondary nanoparticle population (homogenous nucleation). This study shed light on the competitive formation mechanism of homogenous and heterogenous nucleation, suggesting the existence of a critical size, beyond which, phase separation occurs and seeds are no longer available in the reaction medium for heterogenous nucleation. These findings may allow one to tailor the synthesis process in order to achieve better control of the materials' features affecting the magnetic behaviour, and consequently, the performances as heat mediators or components for data storage devices.

Ionic liquid-loaded triazine-based magnetic nanoparticles for promoting multicomponent reaction

A novel hybrid magnetic ionic-liquid as a heterogeneous catalyst was synthesized by hybridization of imidazolium based-ionic liquid onto the nitrogen rich magnetic nanocomposite. The resulting catalyst (n-Fe₃O₄@SiO₂-TA-SO₃H IL) has two advantages besides recyclability: (i) high capacity of functional-SO₃H group with imidazolium-IL cation for promoting symmetric and asymmetric Hantzsch reaction and (ii) easy recovery. Caused by the polymeric and magnetic nature of the n-Fe₃O₄@SiO₂-TA-SO₃H IL, large quantities of acidic groups were bound to the n-Fe₃O₄@SiO₂-TA surface, which reduced the catalyst mass applied to the catalytic reaction. Moreover, superior catalytic performance and outstanding recyclability of n-Fe₃O₄@SiO₂-TA-SO₃H IL in mild condition make this method a green pathway for manufacture of satisfactory chemicals.

Fe3O4@Glycerol-Cu as a novel heterogeneous magnetic nanocatalyst for the green synthesis of 2-amino-4H-chromenes

In the present study, the Fe₃O₄@Glycerol-Cu complex supported magnetically as a nanoparticle was prepared by grafting. Firstly, Fe₃O₄ NPs were synthesized by FeCl₃.6H₂O and FeCl₂.4H₂O according to the reported method, and subsequently, the prepared MNP with 3-chloropropyltrimethoxysilane. After that, the support-glycerol was functionalized on the surface of MNP-(CH₂)₃Cl for graft and stabilization of copper metal. Our purpose is to use the Fe₃O₄@Glycerol-Cu as a green, recoverable, novel, and affordable nanocatalyst in the effective synthesis of 2-amino-4H-chromenes. FT-IR, XRD, TGA, BET, VSM, TEM, and SEM-EDX techniques were examined to characterize this nanocatalyst. This result demonstrates that copper and organic compounds have appropriately reacted, with the support of MNP-(CH₂)₃Cl, and the crystalline structure have preserved in the MNP-(CH₂)₃Cl/Glycerol-Cu nanocatalyst confirmed the formation of the base Cu complex grafted on the surface of the nanoparticles. Finally, as can be seen, the nanoparticle size is 5-15 nm. This heterogeneous nanocatalyst illustrated excellent recyclable behavior, and can be used several times without notable reduction of its activity.

Greener Syntheses of Coumarin Derivatives Using Magnetic Nanocatalysts: Recent Advances

Coumarins (2H-1-benzopyran-2-ones) are an important group of biological heterocyclic compounds present in various parts of many plant species, encompassing an array of biological and pharmaceutical activities. In view of the importance of coumarins in heterocyclic chemistry and biological sciences and recent advances in the design of magnetic nanocatalysts, we present herein recent developments pertaining to their synthesis exclusively using magnetic nanoparticles, which can be retrieved easily and thus conform to the tenets of greener synthesis. The preparation of various types of coumarins such as Pechmann-based coumarins, bis coumarins, pyranocoumarins, and coumarin derivatives bearing amine moiety, linked to nicotinonitriles, N-coumarin-2-furanone, and pyrrole-linked chromene derivatives using nanocatalysts with a Fe₃O₄ core are described. This review covers the synthetic developments in the recent years 2012-2021 and focuses entirely on the synthesis of coumarins in the presence of magnetic nanocatalysts using greener approaches such as solvent-free conditions or deploying alternative activation methods, namely microwave or ultrasound irradiation.

Silica-coated modified magnetic nanoparticles (Fe3O4@SiO2@(BuSO3H)3) as an efficient adsorbent for Pd2+ removal

It is crucial to fabricate cost-effective and efficient strategies for monitoring and eliminating hazardous metals in the water supplies. Among the many techniques, adsorption is one of the most powerful and facile ways for eliminating pollutants from effluents. It is also crucial to engineering high-performance low-cost adsorbents. In this regard, herein, Fe₃O₄@SiO₂@(BuSO₃H)₃ as a modified core-shell magnetic silica nanoparticle embodies good selectivity to extract toxic metal ions from aquatic media. The present work investigated the removal performance of the magnetic adsorbent towards Pd²⁺ cation amongst the other heavy metal ions including Co²⁺, Pb²⁺, Hg²⁺, Cd²⁺, Cu²⁺, Zn²⁺ in aqueous solution. The flame atomic absorption spectrometry (FAAS) was utilized to assess the removal efficiency of the adsorbent. Several experimental parameters including elution condition, initial Pd(II) concentration, adsorbent dosage, initial pH of the solution, and contact time were explored to achieve the optimal conditions. The data of adsorption were very well with the Langmuir isotherm model, according to the adsorption isotherm mechanism experiments. In conclusion, this study lays the way for the development of novel magnetic adsorbents with high removal efficiencies for the removal of toxic metal ions from aqueous environment.

Single-ion chelation strategy for synthesis of monodisperse Pd nanoparticles anchored in MOF-808 for highly efficient hydrogenation and cascade reactions

Ultrafine Pd nanoparticles are prepared using a single-ion precursor on a MOF-808 carrier. The ligand 2,3-pyrazinedicarboxylic acid (Pza) is dispersed in porous MOF-808 via grafting on formic acid sites, and thus Pd²⁺ ions are chelated by Pza to form a new single-ion precursor Pd@MOF-808-Pza. Then a Pd-nano@MOF-808-Pza catalyst is prepared by direct reduction of this precursor using NaBH₄. Material characterization reveals the homogeneous dispersion of 3-6 nm Pd nanoparticles within the MOF-808 matrix. Pd-nano@MOF-808-Pza exhibits excellent catalytic activity in the hydrogenation of unsaturated nitrogen-containing compounds, and other typical reactions, such as the Knoevenagel condensation, Suzuki/Heck cross-coupling, and hydrogen tandem reactions. In addition, density functional theory (DFT) calculations are carried out to elucidate the chelation of Pd²⁺ ions by Pza on MOF-808 and propose mechanisms of hydrogenation reactions. This work provides an effective reduction catalyst, and more importantly, a single-ion chelation strategy for design and synthesis of metal supported catalysts.

CuCe-Ferrite/TiO2 Nanocomposite as an Efficient Magnetically Separable Photocatalyst for Dye Pollutants Decolorization

In this work, a magnetically separated photocatalyst with great efficiency CuCe-Ferrite/TiO2 composite was prepared and characterized by X-ray diffraction (XRD), UV–Vis spectrophotometry, Fourier transformer infra-red spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM). Single-phase cubic spinel was formed by calcining the prepared sample at a temperature of 550 °C, according to the results. Different concentrations of reactive red 250 (RR250) dye photodegradation was evaluated using different doses of CuCe-ferrite/ TiO2 and TiO2 NPs. Higher efficiency of RR250 photodegradation up to 100% was obtained using CuCe-ferrite/ TiO2. The photodegradation efficiency was confirmed using chemical oxygen demand (COD) test of both treated and untreated samples. The oxidation process was mostly mediated by photogenerated .O2− according to scavenger test results. The catalyst possess higher photodegradation efficiency even after regeneration for ten times.

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Synthesis of Cu(OH)2 nanowires modified by Fe3O4@SiO2 nanocomposite via green and innovative method with antibacterial activity and investigation of magnetic behaviours

In this study, green synthesis of modified Cu(OH)₂ nanowires by Fe₃O₄@SiO₂ core-shell nanospheres was easily performed via chemical reduction. In other words, the direct coating of Cu(OH)₂ on Fe₃O₄@SiO₂ was successfully realized without the extra complicated procedures. Various concentrations of synthesized nanocomposites were tested on pathogenic and nosocomial bacteria. In this study, the structural information and characterization of Fe₃O₄@SiO₂/Cu(OH)₂ nanowires (FSCNWs) were obtained using FE-SEM, FT-IR, EDX and X-ray diffraction. This nanocomposite can effectively kill important infectious bacteria, including Staphylococcus aureus, Escherichia coli, Staphylococcus saprophyticus, Pseudomonas aeruginosa and Klebsiella pneumoniae. Studies have shown that FSCNW nanocomposites affect common antibiotic-resistant bacteria. This result confirms the function of FSCNW as an effective, beneficial and environmentally friendly antibacterial agent that can used in a wide range of applications in medicine. FSCNWs can be separated conveniently from bacteria-containing solutions using a magnet. Compared with nanocomposites based on other metals such as silver and gold, the use of FSCNWs in water treatment has been recommended because of the precursor of copper for its low price and less toxicity. In addition to its special properties such as mild reaction conditions, green synthesis methods, admissible magnetic properties, easy separation, high antibacterial activity and beneficial efficiency.

Ag NPs supported chitosan-agarose modified Fe3O4 nanocomposite catalyzed synthesis of indazolo[2,1-b]phthalazines and anticancer studies against liver and lung cancer cells

In this article we report a novel Ag NPs fabricated chitosan-agarose composite functionalized core-shell type Fe₃O₄ nanoparticle (Ag/CS-Agar@Fe₃O₄). The biogenic material was analyzed over a number of physicochemical methods like, FT-IR, FE-SEM, TEM, EDX, XRD, VSM and ICP-OES. In catalytic exploration we aimed the synthesis of diverse 2H-indazolo0-b]phthalazine-trione derivatives via one-pot three component coupling of phathalalhydrazide, dimedone and different aldehydes. It afforded good to excellent yields under solvent-less conditions. Robustness of the catalyst was justified by catalyst recyclability for consecutive 10 times, hot filtration and leaching tests. Again, biological activity of the material was evaluated by studying the antioxidant and cytotoxicity properties over lung and liver cancer cell lines. Antioxidant potential of Ag/CS-Agar@Fe₃O₄ was assessed by DPPH radical scavenging studies and the corresponding IC50 was found to be 96.57 μg/mL. Liver and lung cancer studies over Ag/CS-Agar@Fe₃O₄ was carried out by MTT assay against HepG2 and A549 cell lines. The corresponding IC50 values were found as 192.35 and 365.28 μg/mL respectively. % Cell viability of the nanomaterial decreased dose dependently over both the cell lines without any cytotoxicity on normal cell line. The results demonstrates Ag/CS-Agar@Fe₃O₄ nanocomposite to be an efficient chemotherapeutic drug against the lung and hepatocellular carcinoma cells.

Functionalized hybrid magnetic catalytic systems on micro- and nanoscale utilized in organic synthesis and degradation of dyes

Herein, a concise review of the latest developments in catalytic processes involving organic reactions is presented, focusing on magnetic catalytic systems (MCSs). In recent years, various micro- and nanoscale magnetic catalysts have been prepared through different methods based on optimized reaction conditions and utilized in complex organic synthesis or degradation reactions of pharmaceutical compounds. These biodegradable, biocompatible and eco-benign MCSs have achieved the principles of green chemistry, and thus their usage is highly advocated. In addition, MCSs can shorten the reaction time, effectively accelerate reactions, and significantly upgrade both pharmaceutical synthesis and degradation mechanisms by preventing unwanted side reactions. Moreover, the other significant benefits of MCSs include their convenient magnetic separation, high stability and reusability, inexpensive raw materials, facile preparation routes, and surface functionalization. In this review, our aim is to present at the recent improvements in the structure of versatile MCSs and their characteristics, i.e., magnetization, recyclability, structural stability, turnover number (TON), and turnover frequency (TOF). Concisely, different hybrid and multifunctional MCSs are discussed. Additionally, the applications of MCSs for the synthesis of different pharmaceutical ingredients and degradation of organic wastewater contaminants such as toxic dyes and drugs are demonstrated.

Sono and nano: A perfect synergy for eco-compatible Biginelli reaction

In this study, we evaluated the performance of nano-γ-Fe2O3–SO3H catalyst in the Biginelli reaction and synthesized 3,4-dihydropyrimidine-2-(1H)-ones. This reaction was carried out under solvent-free and ultrasonic irradiation conditions and belonged to one-pot multicomponent reactions (MCRs) with an adopted aromatic aldehyde, ethyl acetoacetate, and urea as starting materials for the beginning of the reaction. The synthesized materials were efficient in synthesizing 3,4-dihydropyrimidine-2-(1H)-ones via the Biginelli reaction under reaction conditions. Thus, the advantages of using nano-γ-Fe2O3–SO3H in the Biginelli reaction are short reaction time, high efficiency, green method, solvent free, and cost-effective. Furthermore, nano-γ-Fe2O3–SO3H as a heterogeneous catalyst can be recycled five times without significantly reducing catalytic activity.

Effect of different molecular coatings on the heating properties of maghemite nanoparticles

In this work, the effect of different molecular coatings on the alternating magnetic field-induced heating properties of 15 nm maghemite nanoparticles (NPs) in water dispersions was studied at different frequencies (159-782 kHz) and field amplitudes (100-400 G). The original hydrophobic oleate coating was replaced with dimercaptosuccinic acid (DMSA) or polyethylene glycol trimethoxysilane (PEGTMS), while cetrimonium bromide (CTAB) or stearic acid-poloxamer 188 (SA-P188) was intercalated or encapsulated, respectively, to transfer the dispersions into water. Surface modification, based on intercalation processes, induced clustering phenomena with the formation of spherical-like assemblies (CTAB and SA-P188), while ligand-exchange strategies kept the particles isolated. The clustering phenomenon has detrimental effects on the heating performances compared with isolated systems, in line with the reduction of Brown relaxation times. Furthermore, broader comprehension of the heating phenomenon in this dynamic system is obtained by following the evolution of SPA and ILP with time and temperature beyond the initial stage.

Supported l-tryptophan on Fe3O4@SiO2 as an efficient and magnetically separable catalyst for one-pot construction of spiro[indene-2,2'-naphthalene]-4'-carbonitrile derivatives

In this work, l-tryptophan functionalized silica-coated magnetic nanoparticles were readily prepared and evaluated as a recyclable magnetic nanocatalyst for the synthesis of spiro[indene-2,2′-naphthalene]-4′-carbonitrile derivatives through the one-pot four-component reaction of malononitrile, cyclohexanone, aromatic aldehydes, and 1,3-indandione. This novel magnetic nanocatalyst was confirmed to be effective and provide products in moderate to excellent yields under reflux conditions. The structure of obtained nanoparticles was characterized using FT-IR, XRD, VSM, EDX, elemental mapping, FE-SEM, and TGA. This synthetic protocol provides several benefits such as excellent yields in short reaction times (64–91%), saving costs, reusability of the catalyst using an external magnet (seven runs), and low catalyst loading.

l-Tryptophan functionalized silica-coated magnetic nanoparticles were prepared and evaluated as a magnetic nanocatalyst for the synthesis of spiro[indene-2,2′-naphthalene]-4′-carbonitrile derivatives through the one-pot four-component reaction.

First biocatalytic synthesis of piperidine derivatives via an immobilized lipase-catalyzed multicomponent reaction

A robust and reusable biocatalyst was constructed via immobilization of lipase onto magnetic halloysite nanotubes for the synthesis of piperidine derivatives.