Organic Inorganic Hybrid Nanocatalyst Research Articles

Palladium fabricated on Fe3O4 as an organic-inorganic hybrid nanocatalyst for the Suzuki and Stille coupling reactions

The Fe3O4@L-Threonine-Pd complex, comprising palladium supported on modified Fe3O4 magnetic nanoparticles (MNPs), has been documented for its use in Stille and Suzuki coupling reactions. The catalyst's environmental friendliness was assessed through a range of techniques including vibrating sample magnetometry (VSM), Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma (ICP), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), energy dispersive X-ray photoelectron spectroscopy (XPS), and X-ray spectroscopy (EDS). Using an external magnet, it is easy to separate nanoparticles from the mixture. The nanocatalyst underwent Metal leaching and heterogeneity testing using the ICP-OES technique, demonstrating its ability to be recovered and reused multiple times without a significant loss of catalytic efficiency or palladium leaching.

A new samarium complex of 1,3-bis(pyridin-3-ylmethyl)thiourea on boehmite nanoparticles as a practical and recyclable nanocatalyst for the selective synthesis of tetrazoles

Boehmite is a natural and environmentally friendly compound. Herein boehmite nanoparticles were primarily synthesized and, then, their surface were modified via 3-choloropropyltrimtoxysilane (CPTMS). Afterwards, a new samarium complex was stabilized on the surface of the modified boehmite nanoparticles (Sm-bis(PYT)@boehmite). The obtained nanoparticles were characterized using thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET), wavelength dispersive X-ray spectroscopy (WDX), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), Inductively coupled plasma mass spectrometry (ICP-MS), dynamic light scattering (DLS), and X-ray diffraction (XRD) pattern. Sm-bis(PYT)@boehmite was used as an environmentally friendly, efficient, and organic–inorganic hybrid nanocatalyst in the homoselective synthesis of tetrazoles in polyethylene glycol 400 (PEG-400) as a green solvent. Notably, Sm-bis(PYT)@boehmite is stable and has a heterogeneous nature. Thus, it can be reused for several runs without any re-activation.

New hybrid approach for desulfurization of diesel fuel using an efficient heterogeneous polyoxometalate nanocatalyst

In this manuscript, the catalytic oxidative desulfurization (CODS) process was proposed to reduce the remove the thiophene (T) and benzothiophene (BT) in diesel fuel. An organic-inorganic hybrid nanocatalyst has been synthesized using 1-Methylimidazolium (MZ) as a transfer agent, CuO nanoparticles as a support, and the highly active mono copper-substituted polyoxotungstate ([PW11CuO39], abbreviated as PW11Cu). Catalytic oxidative desulfurization involves the simultaneous use of extraction technique by an ionic liquid ([BMIM][PF6]) and catalytic oxidation by a suitable heterogeneous catalyst. The experimental condition was optimized by response surface methodology. The removal efficiency in the compounds was as follows: T < BT. In addition, the kinetic behavior of the removal of all sulfur compounds was according to a quasi-first-order model. The nanocomposite was prepared via sol-gel method and finally calcined at 400 °C for 4 h. The materials characterized by means of FT-IR, UV–vis, XRD, and SEM techniques. The response optimization for extractive-catalytic oxidative desulfurization was performed for the removal efficiency of T and BT. The optimum condition was determined as 14.43 min, 40.52 °C for reactor temperature, 86.27 mg for nanocatalyst dosage and 23.99% for oxidant concentration. According to the obtained results, the removal efficiency of thiophene and benzothiophene of diesel fuel could reach 98% and 99%, respectively. The synthesized heterogeneous nanocatalyst could be separated and recycled successfully after 5 times. This system is suggested as an effective strategy with a great potential in the preparation of clean gasoline fuel.

Sum of ranking differences in studies on high performance of catalytic oxidative denitrogenation and desulfurization of model fuel using efficient organic–inorganic hybrid nanocatalyst

Sum of ranking differences in studies on high performance of catalytic oxidative denitrogenation and desulfurization of model fuel using efficient organic–inorganic hybrid nanocatalyst

Synthesis of a new nanocomposite based on sandwich-type silicotungstate and polyvinyl alcohol with superior catalytic activity for deep desulfurization of real/thiophenic mode fuel

For preparation of ultra-clean real gasoline fuel, a new cone-like amphiphilic nanocomposite (TBASi2W18Cd4@PVA) has been synthesized by supporting cadmium containing sandwich-type silicotungstate polyoxometalate ((n-C4H9)4N)7H5Si2W18Cd4O68 (TBASi2 W18Cd4) on polyvinyl alcohol (PVA) as an organic-inorganic hybrid nanocatalyst for catalytic oxidative desulfurization (CODS) of real fuel and thiophenic model fuels. The synthesized samples were characterized using elemental analysis, FT-IR, UV–vis, 113Cd NMR, 29Si NMR, XRD and SEM techniques. The catalytic activity of TBASi2W18Cd4@PVA nanocomposite was tested on thiophenic model fuels and real gasoline fuel in the presence of CH3COOH/H2O2 as an oxidant. After examining TBASi2W18Cd4@PVA nanocomposite in the CODS processes, optimum effective properties were investigated. The average efficiency of the nanocatalyst (TBASi2W18Cd4@PVA) was 98% by optimum values of the properties (catalyst dosage, temperature, oxidation system, different types of catalysts). It has great reusability with 96% of effectiveness after five runs. The CODS mechanism is proposed based on the obtained results, the kinetics were in agreement with the pseudo-first-order model. Based on the obtained results, it could be considered as an effective and industrial-scale nanocatalyst for the desulfurization of refractory sulfur compounds in extremely mild conditions.

One‐pot multicomponent synthesis of novel 2‐(piperazin‐1‐yl) quinoxaline and benzimidazole derivatives, using a novel sulfamic acid functionalized Fe3O4 MNPs as highly effective nanocatalyst

The immobilization of sulfonic acid on the surface of Fe3O4 magnetic nanoparticles (MNPs) as a novel acid nanocatalyst has been successfully reported. The morphological features, thermal stability, magnetic properties, and other physicochemical properties of the prepared superparamagnetic core–shell (Fe3O4@PFBA–Metformin@SO3H) were thoroughly characterized using Fourier transform infrared (FTIR), X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDS), field‐emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis–differential thermal analysis (TGA‐DTA), atomic force microscopy (AFM), dynamic light scattering (DLS), Brunauer–Emmett–Teller (BET), and vibrating sample magnetometer (VSM) techniques. It was applied as an efficient and reusable catalyst for the synthesis of 2‐(piperazin‐1‐yl) quinoxaline and benzimidazole derivatives via a one‐pot multiple‐component cascade reaction under green conditions. The results displayed the excellent catalytic activity of Fe3O4@PFBA–metformin@SO3H as an organic–inorganic hybrid nanocatalyst in condensation and multicomponent Mannich‐type reactions. The easy separation, simple workup, excellent stability, and reusability of the nanocatalyst and quantitative yields of products and short reaction time are some outstanding advantages of this protocol.

L-Arginine complex of copper on modified core–shell magnetic nanoparticles as reusable and organic–inorganic hybrid nanocatalyst for the chemoselective oxidation of organosulfur compounds

In this paper, we report the fabrication and characterization of a stable heterogeneous nanostructure catalyst of copper immobilized on Fe3O4@SiO2@l-Arginine, for the oxidation of sulfides and oxidative coupling of thiols. The prepared nanocatalyst has been characterized by different techniques such as FTIR, XRD, SEM, TEM and TGA. These nanoparticles were the effective catalyst for selective oxidation of sulfides and oxidative coupling of thiols using 30% H2O2. The suggested method offers several prominent advantages such as mild condition, use of magnetically reusable catalyst, simple workup procedure, good to high yields of products and great selectivity.

Guanidine complex of copper supported on boehmite nanoparticles as practical, recyclable, chemo and homoselective organic–inorganic hybrid nanocatalyst for organic reactions

Boehmite (BO) nanoparticles (NPs) were prepared via the injection of aqueous NaOH solution to aqueous aluminum nitrate solution at room temperature. Afterwards, a new complex of copper was immobilized on BO‐NPs (Cu‐Guanidine@BO‐NPs). This heterogeneous nanocatalyst was used as a practical, recyclable, chemo and homoselective nanocatalyst in the organic processes, i.e. the preparation of tetrazole five‐membered heterocycles and chemoselective sulfoxidation of sulfides using H2O2 as oxidant. In this sense, the prepared nanocatalyst was characterized by AAS, N2 adsorption–desorption isotherms, WDX, EDS, SEM, and TGA techniques. The reusability of this catalyst was investigated in the described organic reactions for several runs without notable loss of its catalytic activity. Moreover, all of the tetrazole and sulfoxide derivatives were isolated in high Turn Over Number (TON) and Turn Over Frequency (TOF) numbers indicating the high activity and selectivity of Cu‐Guanidine@BO‐NPs in the described reactions.

L-cysteine complex of palladium onto mesoporous channels of MCM-41 as reusable, homoselective and organic–inorganic hybrid nanocatalyst for the synthesis of tetrazoles

In this study, ordered structure with a hexagonal arrangement MCM-41 was synthesized and functionalized with L-cysteine group and further palladium particles has been supported on its surface (L-cysteine-Pd@MCM-41). The prepared catalyst is well characterized by various techniques such as low-angle X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption–desorption measurement isotherms, energy-dispersive X-ray spectroscopy (EDS), X-ray Mapping (WDX), scanning electron microscopy (SEM) and inductively coupled plasma (ICP) techniques. The collected data from all techniques provided evidence that palladium complex was immobilized onto MCM-41 pores. The obtained nanocatalyst demonstrated excellent activity as a new heterogeneous catalyst for the homoselective synthesis of 5-substituted 1H-tetrazole derivatives. This method has the advantages of simple methodology, eco-friendly and simplicity in the separation of catalyst, shorter reaction times, and high yields of the product. Finally, easy catalyst recovery was achieved and the catalyst could be recycled for six times without a significant decrease in activity and selectivity.

Palladium fabricated on boehmite as an organic–inorganic hybrid nanocatalyst for C–C cross coupling and homoselective cycloaddition reactions

Pd-adenine@boehmite has been prepared and characterized by FT-IR, BET, SEM, EDS, WDX, TGA, XRD and AAS techniques and further was used as catalyst in organic reactions. The reused catalyst was characterized by TEM, EDS, WDX, AAS and FT-IR techniques.

Quaternized polyhedral oligomeric silsesquioxanes stabilized Pd nanoparticles as efficient nanocatalysts for reduction reaction

Hydrophilic quaternized polyhedral oligomeric silsesquioxane (QPOSS) stabilized palladium nanoparticles hybrids (PdNPs@QPOSS) were successfully constructed for catalytic reduction of organic dyes and nitrophenols. The size of PdNPs can be effectively regulated through the molar ratio between QPOSS and Pd precursors. Uniformly dispersed nano-sized QPOSS encapsulated ultra-fine PdNPs with average diameter of 2.38 nm were obtained as the molar ratio of precursors was 1:8. It was found that low-dose PdNPs@QPOSS nanohybrids as catalysts exhibited outstanding catalytic reduction activity for methylene blue (MB) and nitrophenol (4-NP) with high conversion frequencies (TOF) of 213.7 and 17.8 min−1 respectively, which is superior to commercial Pd/C catalyst. The nanocatalysts we prepared could be stably dispersed in water for one month and there was no significant loss of catalytic activity in four catalytic cycle. The enhanced catalytic activity and good stability can be attributed to QPOSS as a stabilizer having strong coordination with as-generated PdNPs. In addition, we evaluated the decolorizing properties of common organic pollutants including methyl orange (MO), congo red (CR), methyl orange (MO), rhodamine 6G (R6G), rhodamine B (RhB), rhodamine 6G (R6G), and nitrophenol derivatives. The organic-inorganic hybrid nanocatalyst PdNPs@QPOSS is very effective in catalytic reduction of a series of colored dyes and nitrophenols, which also means that the nanohybrid as catalyst has a wide range of applications in industrial degradation of organic pollutants in wastewater.

Sustainable approach to the synthesis of 1,4-disubstitued triazoles using reusable Cu(II) complex supported on hydroxyapatite-encapsulated α-Fe2O3 as organic–inorganic hybrid nanocatalyst

A novel Cu(II) complex supported on hydroxyapatite-encapsulated α-Fe2O3 as organic–inorganic hybrid nanocatalyst (α-Fe2O3@Hap@Cu) was synthesized and used in the preparation of 1,2,3-triazole derivatives under green reaction conditions. In this protocol, water was used as solvent under aerobic conditions at room temperature, with low catalyst loading, while ensuring the recovery and reusability of the catalyst. The catalyst affords excellent selectivity in formation of the desired products in short reaction time (10–35 min) and excellent yields (85–98%). The paramagnetic nature of the catalyst led to its easy and convenient separation by an external magnet and reused for 11 consecutive runs without significant loss in activity. The structure of the catalyst was established by FT-IR, XRD, SEM, TEM, EDX, VSM and TGA analyses.

Modification of boehmite nanoparticles with Adenine for the immobilization of Cu(II) as organic–inorganic hybrid nanocatalyst in organic reactions

Boehmite nanoparticles are aluminum oxide hydroxide (γ‐AlOOH) particles, which has large specific surface area (>120 m2 g−1) and can be prepared using an inexpensive procedure in water. Herein, we present an economical, simple, and environmentally friendly route for the preparation of a copper catalyst on Adenine coated boehmite nanoparticles (Cu–Adenine@boehmite). This catalyst has been characterized by several techniques such as SEM, XRD, AAS, ICP and TGA analysis. Cu–Adenine@boehmite was applied as highly efficient and reusable nanocatalyst in carbon–carbon coupling reactions between various aryl halides and sodium tetraphenyl borate, phenylboronic acid, or 3,4-diflorophenylboronic acid under aerobic conditions, palladium-free and phosphine-free ligand. Also this catalyst was applied for the synthesis of polyhydroquinoline derivatives. In continuation, selective oxidation of sulfides to sulfoxides using hydrogen peroxide (H2O2) was studied in the presence of Cu–Adenine@boehmite as catalyst. The synthesis of sulfoxides using H2O2 in the presence of Cu–Adenine@boehmite does not generate waste and any byproducts. This catalyst was reused for several times in CC coupling reaction without loss of its catalytic activity. Reused catalyst was characterized by SEM, XRD and ICP techniques. Heterogeneity and stability of Cu–Adenine@boehmite were studied by hot filtration test, poisoning test and ICP analysis.

Green and efficient organic–inorganic hybrid nanocatalyst for oxidative desulfurization of gasoline

A new organic–inorganic hybrid nanocomposite (TBA‐Si2W18Mn4@SAB) was synthesized by supporting quaternary ammonium salt of sandwich‐type polyoxometalate (TBA‐Si2W18Mn4) on sodium‐activated bentonite (SAB) for catalysing an oxidative desulfurization (ODS) process. The synthesized materials were characterized by means of elemental analysis, 29Si NMR, Fourier transform infrared and UV–visible spectroscopies, X‐ray diffraction and scanning electron microscopy. The proposed ODS process was successfully developed on the basis of the catalytic oxidation of organosulfur compounds using TBA‐Si2W18Mn4@SAB as catalyst and CH3COOH/H2O2 as oxidizing agent. The removal of the sulfur content of gasoline reached 97% at a temperature of 35°C after 1 h using 0.10 g of the prepared catalyst. Various experiments were conducted to investigate the effects of reaction time, catalyst amount, reaction temperature and catalyst type on sulfur removal efficiency. The heterogeneous TBA‐Si2W18Mn4@SAB catalyst was found to be reusable for five times. The obtained data illustrated that the use of the TBA‐Si2W18Mn4@SAB/CH3COOH/H2O2 oxidation system could be a convenient strategy for reducing the sulfur content of gasoline fuel under moderate reaction conditions.

Fabrication of Core-Shell-Structured Organic-Inorganic Hybrid Nanocatalyst for the Expedient Synthesis of Polysubstituted Oxazoles via Tandem Oxidative Cyclization Pathway.

The quest for designing efficient heterogeneous catalytic systems for tandem oxidative cyclization reactions has provided a great impetus to research efforts, as it enables the step-economic construction of complex heterocyclic molecules as well as confers the benefits of a facile catalytic recovery. In the present study, we disclose a new core–shell-structured organic–inorganic hybrid copper nanocatalyst fabricated via the covalent grafting of 2,2′-dipyridyl ketone ligand on amine-functionalized silica-encapsulated magnetite nanoparticles, followed by its metallation with cupric acetate for the tandem oxidative cyclization of amines and β-ketoesters, leading to the production of biologically active polysubstituted oxazole moieties. This programmed catalytic protocol proceeds via the formation of intermolecular C–C and C–N bonds by single-step synthesis and accommodates a broad combination of reaction coupling partners.

Efficient and selective oxidation of alcohols in water employing palladium supported nanomagnetic Fe3O4@hyperbranched polyethylenimine (Fe3O4@HPEI.Pd) as a new organic–inorganic hybrid nanocatalyst

Palladium immobilized magnetic nanoFe3O4@hyperbranched polyethylenimine (Fe3O4@HPEI.Pd) was prepared according to a simple and cost effective pathway and it was employed as a new efficient and selective organic–inorganic hybrid nanocatalyst for the aqueous oxidation of primary and secondary alcohols to their corresponding products in good yields applying oxone (potassium hydrogen monopersulfate) and H2O2 as an oxidant at room temperature. Moreover, the catalytic system was reused at least 13 times without significant loss of activity. The complete characterization of this efficient nanocatalyst was investigated by FTIR, UV–Vis, TEM, SEM, XRD, TGA, VSM, ICP and EDX techniques.

Preparation and application of a magnetic organic-inorganic hybrid nanocatalyst for the synthesis of α-aminonitriles

This article is the first report of the catalytic application of copper ferrite-coated chitosan in organic reactions as a bio-nanocomposite. CuFe2O4/chitosan was used as a hybrid nanocatalyst for the multicomponent Strecker synthesis of α-aminonitriles by using aryl aldehydes, trimethylsilyl cyanide (TMSCN) and aromatic amines at room temperature in ethanol as a green solvent. The catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The nanocatalyst was recovered and reused several times without significant loss of catalytic activity. The organic products were obtained easily without need for column chromatography in good-to-excellent yields. A facile and highly efficient synthesis of α-aminonitriles is reported via a one-pot threecomponent condensation reaction of aryl aldehydes, trimethylsilyl cyanide and aniline at room temperature in the presence of CuFe2O4/chitosan as a hybrid nanocatalyst in ethanol as a green solvent.

Magnetically separable silica@Fe3O4 core–shell supported nano-structured copper(II) composites as a versatile catalyst for the reduction of nitroarenes in aqueous medium at room temperature

In this paper, the fabrication of a highly efficient magnetically separable organic–inorganic hybrid nanocatalyst has been reported by covalently immobilizing the copper(II) acetylacetonate complex over amine functionalized silica@magnetite nanoparticles. The prepared nanocatalyst was characterized by electron microscopy techniques (SEM and TEM with EDS), X-ray diffraction (XRD), vibrational sampling magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR) and atomic absorption spectroscopy (AAS) techniques. The catalytic performance of the resulting nano-composites was examined for the degradation of various organic nitro-analogues in aqueous medium at room temperature using sodium-borohydride as the source of hydrogen. This nano-catalytic system selectively reduces the nitro group even in presence of other sensitive functional groups. To achieve the best catalytic efficacy, various parameters such as catalyst loading, reaction time, effect of various bases and solvents etc. were optimized. The reaction kinetics for the reduction of o-nitroaniline to benzenediamine was studied by UV–vis spectroscopy, and its apparent rate constant was determined and compared with different copper nanocatalysts. The identification of organic residues and purity of the obtained products was analysed by GC–MS. The acquisition of this nanocatalyst has been demonstrated by employing the catalyst in hot filtration and reusability test, and the results obtained from the tests show negligible metal leaching. The nano-catalytic system can be efficiently recovered using simple magnet and reused for multiple cycles without appreciable loss in its catalytic activity. In addition, the stability of the recycled catalyst has been proved by SEM and VSM techniques. It is noteworthy that the key-features like mild reaction conditions, simple work-up procedure, high turnover frequency (TOF), no use of toxic organic solvents, ease in recovery and reusability of the catalyst makes the present protocol more fascinating from an environmental and economic point of view.

Zirconium(IV)-modified silica@magnetic nanocomposites: Fabrication, characterization and application as efficient, selective and reusable nanocatalysts for Friedel–Crafts, Knoevenagel and Pechmann condensation reactions

Abstract A highly efficient and magnetically retrievable zirconium(IV) based nanocatalyst has been synthesized by covalent grafting of 3-hydroxy-2-methyl-1,4-naphthoquinone onto amine functionalized silica coated magnetic nanoparticles followed by complexation with ZrOCl2. The structural and magnetic properties of obtained nanocatalyst are identified by TEM, SEM, XRD, EDS, VSM and FT-IR analyses. The potential of resultant organic–inorganic hybrid nanocatalyst was effectively evaluated for the range of organic transformations such as Friedel–Crafts, Knoevenagel and Pechmann condensation reactions. The magnetically recoverable nano-hybrid catalyst presented high TON and chemoselectivity with the ease of reusability for multiple cycles without any appreciable loss in its catalytic activity.

Silver nanoparticles distributed into polyaniline bridged silica network: A functional nanocatalyst having synergistic influence for catalysis

A novel organic–inorganic hybrid nanocatalyst, Ag nanoparticles supported poly[N-(3-Trimethoxy silyl)propyl]aniline ([email protected]), was prepared by a simple one-step method. X-ray diffraction analysis, field emission transmission electron microscopy and X-ray photo electron spectroscopy reveal the coexistence of Ag nanoparticles (average size ∼ 10 nm) and PTMSPA in [email protected] N2 adsorption–desorption experiments provide the textural properties of the catalyst, such as surface area (86.6 m2/g), pore volume (1.3 × 10− 1 cm3/g) and pore size (4.2 nm). UV–visible spectroscopy was used to follow the kinetics of reduction of 4-nitrophenol (4-NP) by sodium borohydride (NaBH4) in the presence of [email protected] catalyst.