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Palladium immobilized on amidoxime‐functionalized magnetic Fe3O4 nanoparticles: a highly stable and efficient magnetically recoverable nanocatalyst for sonogashira coupling reaction
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Hojat Veisi Alireza Sedrpoushan Behrooz Maleki Malak Hekmati Masoud Heidari Saba Hemmati 《应用有机金属化学》2015,29(12):834-839
We describe the synthesis of a novel Fe3O4/amidoxime (AO)/Pd nanocatalyst by grafting of AO groups on Fe3O4 nanoparticles and subsequent deposition of Pd nanoparticles. Prior to grafting of AO, the 2‐cyanoethyl‐functionalized Fe3O4 nanoparticles prepared through combining 2‐cyanoethyltriethoxysilane and Fe3O4 were treated with hydroxylamine. The AO‐grafted Fe3O4 nanoparticles were then used as a platform for the deposition of Pd nanoparticles. The catalyst was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, scanning and transmission electron microscopies, vibrating sample magnetometry, wavelength‐ and energy‐dispersive X‐ray spectroscopies and inductively coupled plasma analysis. Fe3O4/AO/Pd is novel phosphine‐free recyclable heterogeneous catalyst for Sonogashira reactions. Interestingly, the novel catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled seven times without any significant loss in activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
53.
Cobalt manganese oxide nanoparticles as recyclable catalyst for efficient synthesis of 2‐aryl‐1‐arylmethyl‐1H‐1,3‐benzimidazoles under solvent‐free conditions
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Hossein Ahmadian Hojat Veisi Changiz Karami Alireza Sedrpoushan Maryam Nouri Fariba Jamshidi Iman Alavioon 《应用有机金属化学》2015,29(5):266-269
Cobalt manganese oxide nanocatalyst was synthesized and it was found that it is a highly efficient green catalyst for the synthesis of 2‐aryl‐1‐arylmethyl‐1H‐1,3‐benzimidazoles under solvent‐free conditions. The marked advantages of this method are the simple experimental procedures, shorter reaction times, high yields of product, reusable and non‐toxic catalyst and solvent‐free conditions. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
54.
A highly stable and efficient magnetically recoverable and reusable Pd nanocatalyst in aqueous media heterogeneously catalysed Suzuki C–C cross‐coupling reactions
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Surface modification of Fe3O4 nanoparticles with triethoxyethylcyanide groups was used for the immobilization of palladium nanoparticles to produce Fe3O4/Ethyl‐CN/Pd. The catalyst was characterized using Fourier transform infrared, wavelength‐dispersive X‐ray, energy‐dispersive X‐ray and X‐ray photoelectron spectroscopies, field‐emission scanning electron and transmission electron microscopies, and X‐ray diffraction, vibrating sample magnetometry and inductively coupled plasma analyses. In this fabrication, cyano groups played an important role as a capping agent. The catalytic behaviour of Fe3O4/Ethyl‐CN/Pd nanoparticles was measured in the Suzuki cross‐coupling reaction of various aryl halides (Ar? I, Ar? Br, Ar? Cl) with phenylboronic acid in aqueous phase at room temperature. Interestingly, the novel catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled seven times without any significant loss in activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
55.
Biosynthesis of palladium nanoparticles as a heterogeneous and reusable nanocatalyst for reduction of nitroarenes and Suzuki coupling reactions
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A facile and green route for the synthesis of palladium nanoparticles (Pd‐NPs) was developed utilizing non‐toxic and renewable natural green tea extract as the reducing, stabilizing and capping agent. The as‐prepared Pd‐NPs@Oak Gum catalyst was characterized using UV–visible spectroscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and energy dispersive X‐ray spectroscopy. The Pd‐NPs@Oak Gum catalyst could be used as an efficient and heterogeneous catalyst for Suzuki coupling reactions between phenylboronic acid and a range of aryl halides containing iodo, bromo and chloro moieties and also for the reduction of nitroarenes using sodium borohydride in an environmental friendly medium. Excellent yields of products were obtained with a wide range of substrates and the catalyst was recycled multiple times without any significant loss of its catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
56.
An in situ generated complex of copper(I) and a biguanide, namely metformin, was found to be a highly efficient homogeneous catalyst in N/O-arylation reactions. The O-arylation of substituted phenols with various aryl iodides and bromides was also achieved using this copper catalyst to afford diaryl ethers in good to excellent yields in DMF. This heterogeneous copper catalyst also promotes the N-arylation of imidazole with a variety of aryl halides (Cl, Br, I) in acetonitrile. 相似文献
57.
Hojat Veisi Mostafa Amiri Amir Hossein Hamidian Javad Malakootikhah Leila Fatolahi Alireza Faraji 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):689-696
Hydantoin bromide is an effective catalyst for chemoselective thioacetalization of aldehydes in the presence of ketones under neutral conditions. In addition, a simple and efficient procedure for the deprotection of 1,3-dithianes and 1,3-dithiolanes of aromatic, aliphatic, and α,β-unsaturated aldehydes and ketones in solvent-free conditions to the corresponding parent carbonyl compounds was successfully carried out with hydantoin bromide in excellent yields. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
58.
Hossein Miar Naimi Hojat Ghonoodi 《Analog Integrated Circuits and Signal Processing》2011,67(2):137-141
Using an analytical approach, new estimation of phase error in LC-Tank quadrature oscillators is proposed. The mismatches
between passive components of LC tanks are considered as the reasons of the phase error. Closed form equations relating LC
mismatches to phase errors are presented. Decreasing quality factor (Q) and increasing coupling factor (k) causes phase error
be less sensitive to mismatches in LC tanks. On the other hand phase noise is inversely proportional to quality factor (Q),
and directly proportional to coupling factor (k), so there is a tradeoff between phase noise and phase error. To evaluate
the analysis, a 5 GHz quadrature LC-Tank oscillator is simulated using TSMC 0.18 μm model technology. The results confirm
the simplicity and high accuracy of the proposed analysis. 相似文献
59.
Hojat Veisi Alireza Sedrpoushan Saba Hemmati Davood Kordestani 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):769-775
Abstract Trichloroisocyanuric acid (TCCA) and N-chlorosuccinimide (NCS) were found to be mild and efficient reagents for the direct oxidative conversion of sulfur compounds to the corresponding arenesulfonyl chlorides in good-to-excellent yields through the oxidative chlorination. The overall process is simple and practical, and it provides convenient access to a variety of aryl or heteroarylsulfonyl chlorides. The mild reaction conditions and the broad substrate scope render this method attractive and complementary to existing syntheses of aryl or heteroarylsulfonyl chlorides. 相似文献
60.
Sulfamic acid heterogenized on functionalized magnetic Fe3O4 nanoparticles with diaminoglyoxime as a green,efficient and reusable catalyst for one‐pot synthesis of substituted pyrroles in aqueous phase
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Surface functionalization of magnetic nanoparticles is an elegant way to bridge the gap between heterogeneous and homogeneous catalysis. We have conveniently loaded sulfonic acid groups on amino‐functionalized Fe3O4 nanoparticles affording sulfamic acid‐functionalized magnetic Fe3O4 nanoparticles (MNPs/DAG‐SO3H) as an active and stable magnetically separable acidic nanocatalyst, which was characterized using X‐ray diffraction, Fourier transform infrared and energy‐dispersive X‐ray spectroscopies, scanning and transmission electron microscopies, vibrating sample magnetometry and elemental analysis. The catalytic activity of MNPs/DAG‐SO3H was probed through one‐pot synthesis of N‐substituted pyrroles from γ‐diketones and primary amines in aqueous phase at room temperature. The heterogeneous catalyst could be recovered easily by applying an external magnet device and reused many times without significant loss of its catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献