Fe3O4/SiO2 nanoparticles: an efficient and magnetically recoverable nanocatalyst for the one-pot multicomponent synthesis of diazepines

Broad-spectrum hybrid-driven triple-interface Z-Scheme 1T/2H phase sailboat-like molybdenum disulfide (MoS2)/protonated N-defect nanoporous graphitic carbon nitride (g-C3N4) nanosheets piezo-photocatalyst: Superior degradation and hydrogen evolution

Incorporating piezo-response into photocatalysis holds great promise for eco-friendly strategies in environmental remediation and sustainable energy conversion. Herein, flexible N-defect nanoporous g-C3N4 nanosheets (NPCNs) was prepared via one-step method, then whose surface was protonated. And existed dense 1T/2H phase and vertical interfaces in non-layer-dependent-piezo-response sailboat-like-MoS2 (Sv-MS) formed by in-situ stresses during nucleation and growth by experiments and MD-simulations. Noble-metal-free Z-scheme PC/VM heterojunction with broad-spectrum absorption, enhanced piezo-response and intimate triple-interface was established by electrostatic self-assembly, performing efficient hybrid-driven piezo-photocatalysis. With a systematic modification of morphology, grain size, phase composition, and surface condition of the components, the optimal PC(3.6H)/VM(u2) exhibited high piezo-photocatalytic rates for degradation of organic dyes and antibiotic (RhB (0.565 min-1), MO (0.052 min-1), MB (1.557 min-1), TC (0.062 min-1)) and hydrogen evolution (3528 μmolg-1h-1) under visible-light and ultrasonic-wave, with maintenance under NIR-light (λmax = 1000 nm) attributed to up-conversion effect (RhB: 0.212 min-1, H2: 2355 μmolg-1h-1). Furthermore, the piezo-photocatalytic mechanism was proposed by experiments and DFT-calculations for effective triple-interface Z-Scheme charge migration. This work provides a rational protocol for constructing diverse-energy-triggered, multiple-interfaces and broad-solar-spectrum (UV-Vis-NIR) piezo-photocatalysts in degradation and hydrogen evolution.

Visible-light promoted catalyst-free (VLCF) multi-component synthesis of spiro indolo-quinazolinone-pyrrolo[3,4-a]pyrrolizine hybrids: evaluation of in vitro anticancer activity, molecular docking, MD simulation and DFT studies

A new and highly efficient visible-light-promoted catalyst free (VLCF) strategy for neat and clean synthesis of spiro indolo-quinazolinone-pyrrolo[3,4-a]pyrrolizine hybrids (6a-d) has been introduced. We have performed visible-light triggered 1,3-Dipolar cycloaddition reaction of maleimide (5a-d) with azomethine ylide generated in situ derived from tryptanthrin (3) and L-proline (4) to obtain desired products (6a-d) in good to excellent yield. Authentication and characterization of product was done using various spectroscopic techniques such as IR, 1H NMR, 13C NMR, Mass spectrometry and single crystal XRD analysis. To explain the reaction spontaneity, product stability, reactivity as well as possible mode of the interaction a quantum chemical investigation was performed and depicted through DFT studies. The synthesized compound 6a was also evaluated for anti-proliferative activity against a panel of five cancer cell lines (MCF-7, MDA-MB-231, HeLa, PC-3 and Ishikawa) and normal human embryonic kidney (HEK-293) cell line by using MTT assay. Compound 6a showed very good in vitro anti-proliferative activity (IC50  = 6.58-17.98 μM) against four cancer cell lines and no cytotoxicity against normal HEK-293. In order to evaluate the anticancer potential of compounds 6a-d, molecular docking was performed against wild type and mutant EGFR. The results suggest that all the compounds occupied the active site of both enzymes, with a strong binding energy (-10.2 to -11.5 kcal/mol). These results have been confirmed by molecular dynamics simulation by evaluating root mean square deviation (RMSD) and root mean square fluctuation (RMSF), along with principal component analysis (PCA).Communicated by Ramaswamy H. Sarma.

First-row transition metal for isocyanide-involving multicomponent reactions (IMCR)

First-row transition metal catalyzed transformations that are able to construct complex molecules from simple, readily obtainable feedstocks have become a keystone of modern synthetic organic chemistry. Particularly, the multicomponent reaction (MCR) involving carbon-carbon (C-C) as well as carbon-heteroatom (C-X) bond formation plays an essential role in many chemical conversions, and insurgencies in these reactions powerfully improve the overall synthetic efficiency. Recently, MCRs emerges rapidly because of its greener sides like eco-friendly nature, swift and straightforward execution, high atom/step economy, and construction of aimed product with lowest or no by-product, usually in quantitative yield. Curiously, the exceptional divalent carbon atoms of isocyanides make them predominantly useful components in multicomponent reactions. As a result of widespread research over the past few decades, numerous well-designed and effective procedures for the first-row TM-catalyzed MCR to afford the various entities have been reported. These aspects are summarized in this review article. A particular focus on comparative discussion of various first-row transition-metal catalyzed isocyanide-based multicomponent reactions through mechanistic details included in the review article.

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.

Four-Component Cyclization of Naphthol/Thionaphthol/Naphthylamine, Formaldehyde, and DBU in Water

A practical and environmentally benign cascade multicomponent condensation of naphthol/thionaphthol/naphthylamine, formaldehyde, and DBU in water without any catalysts has been achieved. A wide variety of dihydrooxazine, dihydrothiazine, and tetrahydrobenzoquinazoline derivatives N-substituted with a tether bearing a caprolactam unit were afforded in moderate to good yields. The advantages of being cost-effective, metal-free, and easily handled and the use of water as medium made this protocol conform with the principle of green synthesis.

pH-responsive glycine functionalized magnetic iron oxide nanoparticles for SARS-CoV-2 RNA extraction from clinical sample

The recent outbreak of the novel corona virus disease 2019 (COVID-19) has been made a serious global impact due to its high infectivity and severe symptoms. The Severe Acute Respiratory Syndrome (SARS-CoV-2) RNA extraction is considered as one of the most important steps in COVID-19 detection. Several commercially available kits and techniques are currently being used for specific extraction of SARS-CoV-2 RNA. However, such methods are time consuming and expensive due to the requirement of trained labors, and several chemical reagents. To overcome the mentioned limitations, magnetic RNA adsorption methodology of glycine functionalized iron oxide nanoparticles (GNPs) was established. It showed an efficient potential in SARS-CoV-2 RNA extraction due to pH responsive nature of GNPs. The highly magnetic pH responsive GNPs were synthesized by one-pot co-precipitation method. Random morphology and average 20 nm size of GNPs were denoted by Transmission Electron Microscopy (TEM). X-ray diffractometer (XRD) showed the crystalline magnetite nature. Fourier transform infrared spectroscopy (FT-IR) and UV-visible spectrometry confirmed the presence of glycine on the surface of magnetic nanoparticles. Furthermore, the magnetic nature and thermal properties of GNPs were examined by vibrating sample magnetometer (VSM) and thermo-gravimetric analysis (TGA), respectively. In this study, glycine performed the role of RNA adsorbent. The adsorption of RNA onto the surface of GNPs was achieved in acidic medium (pH 6). In contrary, the elution of RNA from the surface of GNPs was achieved in basic medium (pH 8). The purity of obtained RNA was analyzed by UV-visible spectrometry. Further, the obtained RNA was examined for the presence of SARS-CoV-2 specific Envelope (E), RNA dependent RNA polymerase (RDRP) and Nucleocapsid (N) genes using an RT-PCR analysis. It showed the sudden rise in amount of these genes after 25 cycles of RT-PCR and hence indicated the efficient RNA extraction by GNPs. Agarose gel electrophoresis was used for validation of the quantity and quality of RNA extracted from SARS-CoV-2 patient's sample. The reusability studies of GNPs were performed by monitoring the repeated use of GNPs for SARS-CoV-2 RNA extraction. This method possesses potential role in the field of disease diagnosis. The extraction results of RNA from SARS-CoV-2 patient's sample indicated that the GNPs have an outstanding property over the current existing extraction protocols. It leads to the new advancements in extraction and detection of RNA.

GRAPHICAL ABSTRACT

Graphical abstract of the pH responsive SARS-CoV-2 RNA extraction by using glycine functionalized magnetic iron oxide nanoparticles (GNPs) which were prepared by modified cost effective one pot chemical synthesis method. Prepared GNPs were characterized by XRD, FT-IR and UV-Visible spectrometry, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Glycine present on the surface of nanoparticles (NPs) played an important role in pH responsive RNA extraction procedure. When nanoparticles added in acidic (pH < 7) medium, glycine gained positive surface charge hence overall surface charge of NPs became positive. Thereby SARS-CoV-2 RNA adsorption/binding occurred on the surface of GNP. Later, the RNA-GNP complex was separated by an external magnet. Separated complex was added in basic (pH > 7) medium to elute RNA from GNP. This phenomenon occurred due to surface negative charge of glycine that caused charge repulsion with RNA. Eluted RNA was examined qualitatively and quantitatively by RT-PCR, nanodrop technique and agarose gel electrophoresis. Results were compared with kit based extracted RNA.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10853-022-07464-6.

Synthesis of N-Benzylideneaniline by Schiff base reaction using Kinnow peel powder as Green catalyst and comparative study of derivatives through ANOVA techniques

The cheap and easy availability of the Kinnow peel waste has reported various applications due to presence of multifunctional groups. Therefore, in present study we explored its application to synthesize N-Benzylideneaniline and its derivatives based on Schiff base reaction. Kinnow peel powder is characterized by FTIR, TEM, SEM, XRD, EDX, and TGA for functional groups, morphology, surface, elements and thermal stability. Benzaldehyde, aniline, and their derivatives such as 4-methyl benzaldehyde, 4-hydroxy benzaldehyde, 4-methoxy benzaldehyde, and 4-methoxy aniline have been used to compare the efficacy of the Schiff base reaction using analysis of variance (ANOVA) and it has been observed that combination of Aniline and benzaldehyde for Schiff base reaction provided 85% yield of relative product.

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.

Selective hydrogenolysis of 5-hydroxymethylfurfural to 2,5-dimethylfuran over cobalt nanoparticle inlaid cobalt phyllosilicate

Fabrication of biofuels and chemicals from renewable biomass is highly desirable to replace petrochemicals. Hydrogenolysis of biomass derived 5-hydroxymethylfurfural (HMF) is a promising way to obtain furanic fuels. In this paper, we describe the preparation of a CoSi-PS catalyst derived from cobalt phyllosilicate using a silica sol as the silica source. CoSi-PS exhibited excellent catalytic performance for the hydrogenolysis reaction of HMF to produce liquid 2,5-dimethylfuran (DMF) biofuel. 100% conversion of HMF and 97.5% selectivity for DMF were achieved at 170 °C and 1.5 MPa H₂ for 4 h, which was superior to most of the reported catalysts. The excellent performance can be attributed to the strong interactions between the metal and support, highly dispersed cobalt nanoparticles and the Lewis acid sites induced by the coordinated unsaturated Co(II) sites in phyllosilicate.

para-Aminobenzoic acid-capped hematite as an efficient nanocatalyst for solvent-free CO2 fixation under atmospheric pressure

Utilization of carbon dioxide by converting it into value-added chemicals is a sustainable remedy approach that stipulates abundant, cheap, non-toxic and efficient catalytic materials. In this study, we have demonstrated the use of para-aminobenzoic acid-capped hematite (PABA@α-Fe₂O₃) as an efficient nanocatalyst for the conversion of epoxides to cyclic carbonates utilizing CO₂. The developed PABA@α-Fe₂O₃ nanocatalyst along with a cocatalyst, tetrabutylammonium iodide (TBAI), was able to convert a variety of epoxide substrates into their corresponding cyclic carbonates under atmospheric pressure and solvent-free conditions. The efficient catalytic activity of the material is attributed to the synergistic effect between α-Fe₂O₃ and the amine group of the PABA molecule present on the surface. Furthermore, the recyclability study and post-catalytic analysis revealed that the developed catalyst can be used for multiple catalytic cycles due to the stable and robust nature of the nanocatalyst. The choice of the PABA@α-Fe₂O₃ nanocatalyst is indeed a sustainable approach from the CO₂ capture and utilization point of view.

An efficient and green one-pot synthesis of tetrahydrobenzo[a]xanthenes, 1,8-dioxo-octahydroxanthenes and dibenzo[a,j]xanthenes by Fe3O4@Agar-Ag as nanocatalyst

Agar-coated Fe₃O₄ nanoparticles (Fe₃O₄@agar) were prepared simply through in situ co-precipitation of Fe²⁺ and Fe³⁺ ions via NH₄OH in an aqueous solution of Agar. Coating of Ag⁺ ions on the surface of the latter followed by mild reduction of Ag⁺ with NaBH₄ gives Fe₃O₄@Agar-Ag NPs. The magnetic Fe₃O₄@Agar-Ag nanocatalyst was characterized thoroughly by FT-IR, XRD, SEM, TEM, VSM, EDX, TGA, and ICP analyses. Its catalytic activity was assessed in the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one, 14-aryl-14H-dibenzo[a,j]xanthenes, and 1,8-dioxo-octahydroxanthene derivatives through a one-pot condensation of dimedone, 2-naphthol, and aryl aldehydes in EtOH. This novel method represents lots of advantages compared to the previous researches, such as avoiding the toxic catalysts, easy method for isolation of the products, satisfying yields, totally clean conditions, and simplicity of the methodology. This catalytic system is attributed to an eco-friendly process, high catalytic activity, and facility of recovery using an external magnet. A novel and magnetically recyclable catalyst known as Fe3O4@Agar-Ag NPs as a heterogeneous catalyst were synthesized by a simple method. Using this facile, efficient, and eco-friendly Nanocomposite, for the different models of xanthene reaction was represented.

Magnetically recoverable nickel-palladium alloy nanocatalysts for direct C-H arylation reactions

Novel magnetically recoverable nanocatalyst comprising nickel-palladium (NiPd) alloy nanoparticles (NPs) supported on reduced graphene oxide (rGO) modified with cobalt ferrite (CoFe₂O₄) NPs was fabricated for the direct C-H arylation of imidazopyridine, imidazole, indolizine and furan with aryl halides. To prepare the presented catalyst, rGO nanosheets were first modified with as-synthesized CoFe₂O₄ NPs and then the obtained CoFe₂O₄-rGO nanocomposites served as a support material for the synthesis of bimetallic NiPd alloy NPs at various compositions. The obtained CoFe₂O₄-rGO/NiPd nanocatalysts were characterized by many advanced analytical techniques including TEM, STEM-EDS, XRD, XPS, and ICP-MS. Next, to optimize the reaction conditions, CoFe₂O₄-rGO/NiPd nanocatalysts with different alloy compositions and their monometallic counterparts (CoFe₂O₄-rGO/Ni and CoFe₂O₄-rGO/Pd) were initially tested in the direct C-H arylation of imidazopyridine with bromobenzene. Among all tested nanocatalysts under the optimum reaction conditions, CoFe₂O₄-rGO/Ni₂₀Pd₈₀ showed the best catalytic activity in terms of the isolated product yields. The C-H arylation reactions were studied over a broad substrate scope (35 examples from 36 substrates) and gave the related biaryl products in good to excellent yields. Besides a broad substrate scope, the late-stage C-H arylation of zolimidine, a gastroprotective drug, was realized under the optimized reaction conditions. Moreover, the CoFe₂O₄-rGO/Ni₂₀Pd₈₀ nanocatalysts were recovered from the reaction medium using a simple magnet and reused in the C-H arylation reactions up to five consecutive runs without a significant drop in the product yield. This study shows that magnetically recoverable Pd nanoalloys are promising heterogeneous catalysts to be used in sustainable C-H functionalization reactions.

Ultrasound-Assisted Iodination of Imidazo[1,2-α]pyridines Via C-H Functionalization Mediated by tert-Butyl Hydroperoxide

A novel metal catalyst-free and environmentally friendly method for the regioselective iodination of imidazo[1,2-α]pyridines at their C3 position is disclosed, which has a wide substrate scope and could be sustainable. This reaction proceeds through ultrasound acceleration in the presence of a green alcohol solvent. Compared with a conventional heating system, the reaction efficiency and the rate are significantly improved and the iodine atom economy is maximized using ultrasound techniques.

Synthesis of triarylpyridines with sulfonate and sulfonamide moieties via a cooperative vinylogous anomeric-based oxidation

Herein, novel magnetic nanoparticles with pyridinium bridges namely Fe3O4@SiO2@PCLH-TFA through a multi-step pathway were designed and synthesized. The desired catalyst and its corresponding precursors were characterized with different techniques such as Fourier transform infrared (FT-IR) spectroscopy, 1H NMR, 13C NMR, Mass spectroscopy, energy dispersive X-ray (EDX) analysis, thermogravimetric/derivative thermogravimetry (TG/DTG) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). In addition, the catalytic application of the prepared catalyst in the synthesis of new series of triarylpyridines bearing sulfonate and sulfonamide moieties via a cooperative vinylogous anomeric-based oxidation was highlighted. The current trend revealed that the mentioned catalyst shows high recoverability in the reported synthesis.

Magnetic nanoparticles (Fe3O4 NPs) fabricated composite microgels and their applications in different fields

This article encircles the research progress of Fe3O4 NPs loaded composite microgel particles. Preparation methodologies, properties and applications of Fe3O4 NPs loaded composite microgel particles are elaborated here. The effect of different factors on the stability and tunable properties of Fe3O4 NPs loaded composite microgel particles was also investigated in detail. These composite particles have exceptional magnetic properties that make them demanding composite nano-formulation in different fields. Applications of these composite microgel particles in different fields as micro-reactor, drug delivery vehicles, and in adsorption and catalysis have also been elaborated in detail. These composite microgel particles can easily be recovered from the reaction mixture by applying an external magnet due to the presence of fabricated Fe3O4 NPs.

Palladium oxide-decorated mesoporous silica on graphene oxide nanosheets as a heterogeneous catalyst for the synthesis of β-substituted indole derivatives

In this work, an efficient and facile strategy has been adopted for the stepwise synthesis of the RGO-MSiO2/PdO hybrid nanomaterial (HY-NM). Herein, a hybrid nanostructure of mesoporous silica over graphene oxide (GO) sheets has been developed followed by immobilizing palladium oxide nanoparticles (PdO NPs), and then it has been utilized for catalyzing a multicomponent reaction (MCR). To authenticate the successful synthesis of the HY-NM and successive immobilization of PdO NPs, various physicochemical characterization techniques were utilized such as SEM, EDAX, HR-TEM, HR-XRD, TGA, BET, FT-IR, and XPS analysis. The activity of the HY-NM has been determined by performing the catalyst-mediated synthesis of β-substituted indole derivatives (yield 90-98%). The excellent catalytic activity of the prepared HY-NM could be observed due to its high surface area and large porosity, which facilitates the penetration and interaction of reactant molecules with the catalytic active species. This protocol eliminates the requirement of further purification after the isolation of the product from the reaction mixture. The ease of handling, recyclability of the catalyst, and simple work-up procedure are the main features of this protocol. The synthesized HY-NM could be recycled for multiple catalytic cycles making it a very effective heterogeneous catalyst.

Magnetite nanoparticles grafted with murexide-terminated polyamidoamine dendrimers for removal of lead (II) from aqueous solution: synthesis, characterization, adsorption and antimicrobial activity studies

In this study, new, efficient, eco-friendly and magnetically separable nanoadsorbents, MNPs-G1-Mu and MNPs-G2-Mu, were successfully prepared by covalently grafting murexide-terminated polyamidoamine dendrimers on 3-aminopropyl functionalized silica-coated magnetite nanoparticles, and used for rapid removal of lead (II) from aqueous medium. After each adsorption process, the supernatant was successfully acquired from reaction mixture by the magnetic separation, and then analyzed by employing ICP-OES. Chemical and physical characterizations of new nanomaterials were confirmed by XRD, FT-IR, SEM, TEM, and VSM. Maximum adsorption capacities (q_m) of both prepared new nanostructured adsorbents were compared with each other and also with some other adsorbents. The kinetic data were appraised by using pseudo-first-order and pseudo-second-order kinetic models. Adsorption isotherms were found to be suitable with both Langmuir and Freundlich isotherm linear equations. The maximum adsorption capacities for MNPs-G1-Mu and MNPs-G2-Mu were calculated as 208.33 mg g^-1 and 232.56 mg g^-1, respectively. Antimicrobial activities of nanoparticles were also examined against various microorganisms by using microdilution method. It was determined that MNPs-G1-Mu, MNPs-G2-Mu and lead (II) adsorbed MNPs-G2-Mu showed good antimicrobial activity against S. aureus ATTC 29213 and C. Parapsilosis ATTC 22019. MNPs-G1-Mu also showed antimicrobial activity against C. albicans ATTC 10231.

Algal magnetic nickel oxide nanocatalyst in accelerated synthesis of pyridopyrimidine derivatives

This research presents a novel biological route for the biosynthesis of nickel oxide nanoparticles (NiO NPs) using marine macroalgae extract as a reducing and coating agent under optimized synthesis conditions. XRD and TEM analyses revealed that phytosynthesized NiO NPs are crystalline in nature with a spherical shape having a mean particle size of 32.64 nm. TGA results indicated the presence of marine-derived organic constituents on the surface of NiO NPs. It is found that biogenic NiO NPs with BET surface area of 45.59 m²g^-1 is a highly efficient catalyst for benign one-pot preparation of pyridopyrimidine derivatives using aqueous reaction conditions. This environmentally friendly procedure takes considerable advantages of shorter reaction times, excellent product yields (up to 96%), magnetically viable nanocatalyst (7 runs), low catalyst loadings, and free toxic chemical reagents.

The first PdO nanoparticle catalyzed one pot synthesis of propargylamine through A3-coupling of an aldehyde, alkyne and amine

Palladium(ii) oxide (PdO) nanoparticles (Nps) were prepared by an environmentally benign hydrothermal method with a new capping agent quercetin.