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1.
A phenoxybutane‐based Schiff base complex of cis‐dioxo‐Mo(VI) was supported on paramagnetic nanoparticles and characterized using powder X‐ray diffraction, infrared, diffuse reflectance and atomic absorption spectroscopies, scanning and transmission electron microscopies and vibrating sample magnetometry. The separable nanocatalyst was tested for the selective epoxidation of cyclohexene, cyclooctene, styrene, indene, α‐pinene, 1‐octene, 1‐heptene, 1‐dodecene and trans‐stilbene using tert‐butyl hydroperoxide (80% in di‐tert‐butyl peroxide–water, 3:2) as oxidant in chloroform. The catalyst was efficient for oxidation of cyclooctene with 100% selectivity for epoxidation with 98% conversion in 10 min. We were able to separate magnetically the nanocatalyst using an external magnetic field and used the catalyst at least six successive times without significant decrease in conversion. The turnover frequency of the catalyst was remarkable (2556 h?1 for cyclooctene). The proposed nanomagnetic catalyst has advantages in terms of catalytic activity, selectivity, catalytic reaction time and reusability by easy separation. 相似文献
2.
Cu(II) Schiff base complex supported on Fe3O4 nanoparticles as an efficient nanocatalyst for the selective aerobic oxidation of alcohols
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Herein, we have prepared a new Cu(II) Schiff base complex supported onto the surface of modified Fe3O4 nanoparticles as highly stable, heterogeneous and magnetically recyclable nanocatalyst for the selective aerobic oxidation of different alcohols. The structure, morphology, chemical composition and magnetic property of the nanocatalyst and its precursors were characterized using FT‐IR, TGA, AAS, ICP‐AES, XRD, SEM, EDS, VSM and N2 adsorption–desorption analyses. Characterization results exhibited the uniform spherical morphology for nanocatalyst and its precursors. A promising eco‐friendly method with short reaction time and high conversion and selectivity for oxidation of various primary and secondary alcohols under O2 atmosphere condition was achieved. The synthesized nanocatalyst could be recovered easily by applying an external magnetic field and reused for least eight subsequent reaction cycles with only negligible deterioration in catalytic performance. 相似文献
3.
In this study, a new polymeric functionalized magnetic nanocatalyst containing a molybdenum Schiff base complex was prepared using a few consecutive steps. Poly (methylacrylate)-coated magnetic nanoparticles were synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the amidation of the methyl ester groups with hydrazine. Polymeric functionalization efficiently provides the advantage that more catalytic units can be grafted on the surface of magnetic nanoparticles. The functionalization process was continued with salicylaldehyde which introduced Schiff base groups on to the surface of the polymeric support. In the final step, the desired catalytic system was prepared via complexation of the Schiff base groups with MoO2(acac)2. The resulting nanoparticles were characterized by infrared spectroscopy, powder X-ray diffraction, scanning and transmission electron microscopy, elemental analysis, inductively coupled plasma optical emission spectrometry, vibrating sample magnetometry and thermogravimetric analysis. This heterogenized catalytic system was also found to be highly active, sustainable and recyclable nanocatalyst in alkene epoxidation. Eventually, the attractive features of the synthesized catalyst such as simple work-up, good stability, magnetic separation, high TOF and high surface area; make it appropriate for oxidation reactions. 相似文献
4.
A Schiff base ligand derived from 5-bromo-2-hydroxybenzaldehyde and 2,2′-dimethylpropylenediamine (H2L) and its corresponding dioxomolybdenum(VI) complex (Mo(O)2L) has been synthesized and characterized by spectroscopic methods. The adsorption of Mo(O)2L on the surface of silica-coated magnetite nanoparticles via hydrogen bonding led to the formation of (α-Fe2O3)–MCM-41–Mo(O)2L as a heterogeneous catalyst. FT-IR and atomic absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize and investigate the new nanocatalyst. A practical catalytic method for the efficient and highly selective oxidation of a wide range of olefins with hydrogen peroxide and tert-butyl hydroperoxide in ethanol over the prepared molybdenum nanocatalyst was investigated. Under reflux conditions, the oxidation of cyclooctene with tert-butyl hydroperoxide or hydrogen peroxide led to the formation of epoxide as the sole product. The catalyst was reused at least six times without a significant decrease in catalytic activity or selectivity, and without detectable leaching of the catalyst. 相似文献
5.
Nanomagnetic bisethylferrocene‐containing ionic liquid supported on silica‐coated iron oxide (Fe3O4@SiO2@Im‐bisethylFc [HC2O4]) as a novel catalyst was designed and synthesized. The described catalyst was recycled and used without change in the time and efficiency of the condensation reaction. The Fourier transform‐infrared spectroscopy (FT‐IR), scanning electron microscopy images, X‐ray diffraction patterns, energy‐dispersive X‐ray spectroscopy, transmission electron microscope and vibrating‐sample magnetometer results confirmed the formation of Fe3O4@SiO2@Im‐bisethylFc [HC2O4] magnetic nanoparticle. The novel bis‐coumarin derivatives were identified by 1H‐NMR, 13C‐NMR, FT‐IR and CHNS analysis. 相似文献
6.
Schiff base‐functionalized boehmite nanoparticle‐supported molybdenum and vanadium complexes: efficient catalysts for the epoxidation of alkenes
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Boehmite nanoparticles, with high surface area and high degree of surface hydroxyl groups, were prepared via hydrothermal‐assisted sol–gel processing of aluminium 2‐butoxide. The produced powder was covalently functionalized with 3‐(trimethoxysilyl)propylamine, and then, in order to support vanadium oxosulfate and molybdenum hexacarbonyl complexes, all the terminal amine groups were changed to Schiff bases by refluxing with salicylaldehyde. These catalysts were applied in the epoxidation of cis‐cyclooctene and other olefins with tert‐BuOOH in CCl4. The catalytic procedures for both catalysts were optimized for various parameters such as solvent and oxidant. Recycling experiments revealed that these heterogeneous nano‐catalysts could be repeatedly applied for the epoxidation of alkenes. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
7.
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. 相似文献
8.
In this work, catalytic performance of a molybdenum Schiff base complex‐supported magnetic support as a nanocatalyst was evaluated for the preparation of 2‐amino‐4H‐benzo[h]chromenes through one‐pot, three component reactions of 1‐naphthol, various aldehydes, and malononitrile under solvent‐free conditions. A promising greener and eco‐friendly method with a short reaction time, high yield of products, and simple work‐up procedure was achieved. The nanocatalyst could be easily separated and regenerated from reaction media by an external magnet and reused at least seven consecutive times with small drops in its catalytic performance. 相似文献
9.
Four new kinds of heterogeneous catalysts for olefins epoxidation were obtained by grafting diamines on organic polymer–inorganic hybrid material, zirconium poly (styrene‐phenylvinylphosphonate)‐phosphate (ZPS‐PVPA), and subsequently coordinating with Schiff base Mo(VI) complexes. The catalysts were characterized by IR, XPS, SEM and TEM. All catalysts were evaluated through the epoxidation of olefins using tert‐BuOOH as oxidant. The heterogeneous catalysts possess the advantages of high conversion, selectivity and excellent reusability. The catalysts were easily separated from the reaction systems and could be reused 13 times without significant loss of catalytic activity. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
10.
Mahdi Mirzaee Bahram Bahramian Parichehr Gholampour Samaneh Teymouri Toktam Khorsand 《应用有机金属化学》2019,33(4)
Fe3O4 core nanoparticles were prepared via a solvothermal process, and then they were covered with a surface hydroxyl‐rich boehmite shell via the hydrothermal‐assisted sol–gel processing of aluminum 2‐propoxide. The outer surface of the boehmite shell was subsequently covalently functionalized with 3‐(tri‐methoxysilyl)‐propylamine or 3‐(tri‐methoxysilyl)‐propyl chloride, and the terminal chlorine groups were treated with imidazole. These compounds were used to support the hexa‐carbonyl molybdenum and oxo‐sulfato vanadium (IV) complexes. The supported catalysts were characterized by the FT‐IR, CHN, ICP, and TEM analysis techniques. They were then used in the epoxidation of cis‐cyclooctene. The catalytic procedures were optimized for different parameters such as the solvent, oxidant, and temperature. The reaction progress was investigated by the gas–liquid chromatography analysis. The catalysts used were simply recovered from the solution by applying a magnet, and recycling the experiments revealed that the heterogeneous nanocatalysts could be repeatedly used for the epoxidation of cis‐cyclooctene. The optimized conditions were also successfully used for the epoxidation of some other alkenes. 相似文献
11.
Mahdi Gholamhosseini‐Nazari Somayeh Esmati Kazem D. Safa Alireza Khataee Reza Teimuri‐Mofrad 《应用有机金属化学》2019,33(4)
A novel magnetic ferrocene‐labelled ionic liquid based on triazolium, [Fe3O4@SiO2@Triazol‐Fc][HCO3], has been synthesized and has been successfully introduced as a recyclable heterogeneous nanocatalyst. The catalytic activity of the novel magnetic nanoparticles was evaluated in the one‐pot three‐component synthesis of a wide variety of Betti bases. A simple, facile and highly efficient green method has been developed for the synthesis of kojic acid‐containing Betti base derivatives at room temperature. Additionally, this new protocol has notable advantages such as short reaction times, green reaction conditions, high yields and simple workup and purification steps. Also, the novel nanocatalyst could be easily recovered using an external magnetic field and reused for six consecutive reaction cycles without significant loss of activity. The newly synthesized nanocatalyst was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller measurements. 相似文献
12.
A new magnetically recoverable nanocatalyst designated as Fe3O4@SiO2@PTMS@Mel‐Naph‐VOcomplex was synthesize by covalent binding of a Schiff base ligand derived from melamine and 2‐hydroxy1naphtaldehyde on the surface of silica coated iron oxide magnetic nanoparticles followed by complexation with VO (acac)2. Characterization of the prepared nanocatalyst was accomplished with FT‐IR, XRD, SEM, HRTEM, VSM and atomic absorption techniques. It was found that the epoxidation of geraniol, trans‐2‐hexen‐1‐ol, 1‐octen‐3‐ol, norbornene, and cyclooctene is highly selective, affording quantitative yields of the corresponding epoxides with tert‐butyl hydroperoxide (TBHP) using Fe3O4@SiO2@Mel‐Naph‐VOcomplex as catalyst. High reaction yields, short reaction times, simple experimental and work up procedure, catalyst stability and excellent reusability even after five‐cycles of usage in the case of geraniol are some advantages of this research. 相似文献
13.
In this paper, guanidine groups (Gn) supported on modified magnetic nanoparticles (Fe3O4–4,4′‐MDI) were synthesized for the first time. The catalyst synthesized was characterized by various techniques such as SEM (Scanning Electron Microscopy), TEM (Transmission electron microscopy), XRD ( X‐ray Diffraction ), TGA (Thermogravimetric ananlysis), EDS ( Energy‐dispersive X‐ray spectroscopy ) and VSM (vibrating sample magnetometer). The catalyst activity of modified MNPs–MDI‐Gn, as powerful basic nanocatalyst, was probed through the Knoevenagel and Tandem Knoevenagel–Michael‐cyclocondensation reactions. Conversion was high under optimal conditions, and reaction time was remarkably shortened. This nanocatalyst could simply be separated and recovered from the reaction mixture by simple magnetic decantation and reused many times without significant loss of its catalytic activity. Also, the nanocatalyst could be recycled for at least seven (Knoevenagel condensation) and six (Knoevenagel and Tandem Knoevenagel–Michael‐cyclocondensation) additional cycles after they were separated by magnetic decantation and, washed with ethanol, air‐dried, and immediately reused. 相似文献
14.
The polymer bound Schiff‐base ligand (PS‐SalGlu) has been prepared from polystyrene bound salicylaldehyde and glutamic acid, and its complex (PS‐SalGlu‐Co) has also been synthesized. The polymer ligand and its complex were characterized by infrared spectroscopy, small area X‐ray photoelectron spectroscopy, and inductively coupled plasma‐atomic emission spectro (ICP‐AFS). In the presence of the complex, cyclohexene can be effectively oxidized by molecular oxygen without reductant. The long‐chain linear aliphatic olefins, such as 1‐octene, 1‐decene, 1‐dodecene and 1‐tetradecene, can be directly oxidized by molecular oxygen catalyzed by PS‐SalGlu‐Co, which affords the 1,2‐epoxy alkane. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
15.
Samaneh Mahmoudi‐GomYek Davood Azarifar Masoumeh Ghaemi Hassan Keypour Masoumeh Mahmoudabadi 《应用有机金属化学》2019,33(6)
A novel Cu (II) Schiff‐base complex immobilized on core‐shell magnetic Fe3O4 nanoparticles (Fe3O4@SPNC) was successfully designed and synthesized. The structural features of these nanoparticles were studied and confirmed by using various techniques including FT‐IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDS), vibrating sample magnetometer (VSM), X‐Ray diffraction (XRD), wavelength dispersive X‐ray spectroscopy (WDX), and inductively coupled plasma (ICP). These newly synthesized nanoparticles have been used as efficient heterogeneous catalytic system for one‐pot multicomponent synthesis of new pyrano[2,3‐b]pyridine‐3‐carboxamide derivatives. Notably, the catalyst could be easily separated from the reaction mixture by using an external magnet and reused for several successive reaction runs with no significant loss of activity or copper leaching. The present protocol benefits from a hitherto unreported MNPs‐immobilized Cu (II) Schiff‐base complex as an efficient nanocatalyst for the synthesis of newly reported derivatives of pyrano[2,3‐b]pyridine‐3‐carboxamide from one‐pot multicomponent reactions. 相似文献
16.
Fe3O4@SiO2@propyltriethoxysilane@o‐phenylendiamine as an environmentally‐benign functionalized silica‐coated magnetic organometallic nanomaterial has been synthesized and characterized by Fourier transforms infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM) images and energy dispersive X‐ray (EDX) and vibrating sample magnetometer (VSM) analyses. Then, its catalytic activity was investigated for the one‐pot three‐component condensation reaction between dimedone, malononitrile and various substituted aromatic aldehydes to afford the corresponding 2‐amino‐4H‐chromene derivatives under mild reaction conditions. This nanocatalyst can be easily recovered from the reaction mixture by using a magnet and reused for at least five times without significant decrease in catalytic activity. 相似文献
17.
Synthesis and characterization of 4‐AMTT‐Pd(II) complex over Fe3O4@SiO2 as supported nanocatalyst for Suzuki‐Miyaura and Mizoroki‐heck cross‐coupling reactions in water
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Immobilization of Pd(II) nanoparticles on silica‐coated modified magnetite particles has been readily achieved via a surface modification of Fe3O4 particles with 4‐amino‐5‐methyl‐4‐H‐1,2,4‐triazole‐3‐thiol (4‐AMTT) as a ligand. This magnetite nanocatalyst was characterized by various analyses such as FT‐IR, SEM/EDX, ICP‐AES, VSM, TEM, XRD, XPS and TGA. This nanocatalyst showed admirable catalytic activity for Suzuki‐Miyaura and Mizoroki‐Heck cross‐coupling reactions under mild conditions in water, and could be simply separated by an outer magnet and reused for several times. 相似文献
18.
Kazem Karami Nasrin Jamshidian Mohammad Mehdi Nikazma Pablo Hervés Amir Rezaei Shahreza Ali Karami 《应用有机金属化学》2018,32(1)
We report a simple process for the synthesis of Fe3O4@SiO2/APTMS (APTMS = 3‐aminopropyltrimethoxysilane) core–shell nanocatalyst support. The new nanocatalyst was prepared by stabilization of Pd(cdha)2 (cdha = bis(2‐chloro‐3,4‐dihydroxyacetophenone)) on the surface of the Fe3O4@SiO2/APTMS support. The structure and composition of this catalyst were characterized using various techniques. An efficient method was developed for the synthesis of a wide variety of biaryl compounds via fluoride‐free Hiyama cross‐coupling reactions of aryl halides with arylsiloxane, with Fe3O4@SiO2/APTMS/Pd(cdha)2 as the catalyst under reaction conditions. This methodology can be performed at 100°C through a simple one‐pot operation using in situ generated palladium nanoparticles. High catalytic activity, quick separation of catalyst from products using an external magnetic field and use of water as green solvent are attributes of this protocol. 相似文献
19.
In the present work, an innovative leach proof nanocatalyst based on dendritic fibrous nanosilica (DFNS) modified with ionic liquid loaded Fe3O4 NPs and CuI salts was designed and applied for the rapid synthesis of imidazo[1,2‐a]pyridines from the reaction of phenyl acetylene, 2‐aminopyridine, and aldehydes in aqueous medium. The structure of the synthesized nanocatalyst was studied by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FT‐IR), flame atomic absorption spectroscopy (FAAS), energy‐dispersive X‐ray (EDX), and X‐ray diffraction (XRD), vapor–liquid–solid (VLS), and adsorption/desorption analysis (Brunauer–Emmett–Teller [BET] equation) instrumental techniques. CuI/Fe3O4NPs@IL‐KCC‐1 with high surface area (225 m2 g?1) and porous structure not only exhibited excellent catalytic activity in aqueous media but also, with its good stability, simply recovered by an external magnet and recycled for eight cycles without significant loss in its intrinsic activity. Higher catalytic activity of CuI/Fe3O4NPs@IL‐KCC‐1 is due to exceptional dendritic fibrous structure of KCC‐1 and the ionic liquid groups that perform as strong anchors to the loaded magnetic nanoparticles (MNPs) and avoid leaching them from the pore of the nanocatalyst. Green reaction media, shorter reaction times, higher yields (71–97%), easy workup, and no need to use the chromatographic column are the advantages of the reported synthetic method. 相似文献
20.
For the first time, a novel, straightforward and inexpensive route for immobilization of metals in Schiff base complex form is reported applying 2,4‐toluenediisocyanate as a precursor of primary amine group. A nickel(II) Schiff base complex supported on nano‐TiO2 was designed and synthesized as an effective heterogeneous nanocatalyst for organic reactions, and well characterized using various techniques such as Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray analysis and thermogravimetric analysis. The catalytic efficiency of the complex was evaluated in selective oxidation of sulfide to sulfoxide by hydrogen peroxide as an oxidant under solvent‐free conditions at room temperature, which successfully resulted in high yield and high conversion of products. Effective factors including solvent type, oxidant and catalyst amount were also optimized. The catalyst shows outstanding reusability and could be impressively recovered for six consecutive cycles without significant change of its catalytic efficiency. 相似文献