- Metallic nanoparticles immobilized in magnetic metal-organic frameworks: Preparation and application as highly active, magnetically isolable and reusable catalysts
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Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this paper, ultrafine noble metallic nanoparticles are incorporated into cauliflower-like porous magnetic metal-organic frameworks (MOFs). With the restriction effects of the pore/surface structure in the MOFs, "surfactant-free" metallic nanoparticles are successfully obtained on a 2-3 nm scale. In addition, both the thickness of MOFs shell and the content of noble metallic NPs are tunable on the MOFs coating. Moreover, the microspheres exhibit excellent performance for the catalytic reduction of p-nitrophenol with a turnover frequency of 3094 h-1. The uniform cavities in the MOFs shell provide docking sites for p-nitrophenol and act as confinement nanoreactors, which greatly improves the catalytic performance. Most importantly, the magnetically responsive microspheres can be easily recovered by a magnetic field and show excellent reusability. The as-prepared catalyst also shows good activity for the reduction of other nitrobenzenes. Consequently, this work provides a highly active, magnetically isolable, and recyclable catalyst, which can be used for various catalytic industrial processes. The fundamental model can be further employed in a variety of biomedical fields including drug delivery and biological molecules separation. the Partner Organisations 2014.
- Zhang, Hai-Juan,Qi, Sheng-Da,Niu, Xiao-Ying,Hu, Jing,Ren, Cui-Ling,Chen, Hong-Li,Chen, Xing-Guo
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- Silver nanoparticles supported on P, Se-codoped g-C3N4 nanosheet as a novel heterogeneous catalyst for reduction of nitroaromatics to their corresponding amines
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P, Se-codoped g-C3N4 (PSeCN) nanosheet was in situ prepared by facile thermal polymerization of melamine, phosphonitrilic chloride trimer, and selenium black powder as the precursors. It was found as a suitable support for the immobilization of silver nanoparticles (Ag NPs). The prepared nanocatalyst was fully characterized via standard analysis methods including EDX, ICP-OES, XRD, FT-IR, SEM, TEM, and BET. This PSeCN/Ag nanocatalyst with a higher specific surface area compared with CN, showed excellent catalytic activity towards the reduction of several nitroaromatic compounds using sodium borohydride (NaBH4) in short reaction times with high efficiency and good selectivity in water as a green solvent. Significantly, the above-mentioned nanocomposite could be reused six times without appreciable loss of its catalytic activity.
- Elhampour, Ali,Heravi, Majid M.,Nemati, Firouzeh,Piri, Mohadese
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- Cobalt oxide NPs immobilized on environmentally benign biological macromolecule-derived N-doped mesoporous carbon as an efficient catalyst for hydrogenation of nitroarenes
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Highly nitrogen-doped mesoporous carbon (N-mC) material incorporated cobalt oxide nanoparticles was synthesized through simple pyrolysis of environmentally friendly chitosan-polyaniline-Co(OAc)2 precursor in one-step. The as-prepared catalyst named CoO&at;N-mC with 14.65 ?wtpercent nitrogen content was characterized by different analysis techniques. The heterogeneous catalyst exhibits outstanding catalytic activity for the reduction of a variety of nitroaromatic compounds in the presence of NaBH4 as a reducing agent in water as a green solvent at 75 ?°C. Utilization of natural biological macromolecules such as chitosan as green and cheap starting material with harmless aniline and earth-abundant cobalt salt, facile synthesis, excellent product yield, short reaction time, high chemoselectivity, sustainable and mild reaction condition, and reusability of catalyst for at least five cycles without any significant decline in the catalytic efficiency are some prominent merits of this new nanocatalyst.
- Elhampour, Ali,Nanadegani, Zahra Soleimani,Nemati, Firouzeh,Rangraz, Yalda
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- Synthesis of water soluble Pd-Piperidoimidazolin-2-ylidene complexes and their catalytic activities in neat water
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Through the strategy of water soluble N-heterocyclic carbene (NHC) ligand, Pd-catalyzed reactions were developed in aqueous media. Therefore, four new piperidoimidazolinium salts (1a-d) consisting of sulfonate (a), esther (b, c) and carboxylic acid (d) functionalities and their water-soluble Pd-NHC complexes (2a-d) were synthesized. The new compounds were characterized by elemental analysis, FTIR, TGA, UV–vis and NMR spectroscopy. The catalytic activities of water soluble Pd-NHC complexes (2a-d) were investigated using the Suzuki-Miyaura (S-M) reaction and the reduction of nitroarenes. We found that the water-soluble polar or ionic groups on piperidoimidazolin-2-ylidine had an effect on the catalytic activity. The water-soluble catalyst can be recycled efficiently and reused six times with only a very slight loss of catalytic activity.
- ?ak?r, Sinem,Türkmen, Hayati
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- Magnetically Recoverable Gold Nanorods as a Novel Catalyst for the Facile Reduction of Nitroarenes Under Aqueous Conditions
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Abstract: In this work, cysteine-functionalized Fe3O4@Carbon magnetic nanoparticles were used for the synthesis of gold nanorods. Fe3O4@C nanoparticles were first prepared by synthesis of Fe3O4magnetic nanoparticles (MNPs), and then carbon-coated MNPs (Fe3O4@C) were synthesized by glucose carbonization using a hydrothermal method. Finally, the gold NRs were loaded on the modified surface of Fe3O4@C MNPs. The designed magnetically recoverable gold nanorods, after full characterization by FTIR, SEM, TEM, TGA, VSM, XRD, and ICP-OES, were applied to the reduction of nitroarenes. The Fe3O4@C@Cys–Au nanorods showed higher performance than Fe3O4@C@Cys–Au nanospheres in a selective facile reduction of nitroarenes to the corresponding aminoarenes in aqueous medium at room temperature using NaBH4. Graphical Abstract: [Figure not available: see fulltext.]
- Lamei, Kamran,Eshghi, Hossein,Bakavoli, Mehdi,Rostamnia, Sadegh
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p. 491 - 501
(2017/02/18)
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- Analysis of structure-activity relationships for the 'B-region' of N-(4-t-butylbenzyl)-N′-[4-(methylsulfonylamino)benzyl]-thiourea analogues as TRPV1 antagonists
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The structure-activity relationships for the 'B-region' of N-(4-t-butylbenzyl)-N′-[4-(methylsulfonylamino)benzyl]thiourea analogues have been investigated as TRPV1 receptor antagonists. A docking model of potent antagonist 2 with the sensor region of TRPV1 is proposed.
- Lee, Jeewoo,Jin, Mi-Kyoung,Kang, Sang-Uk,Su, Yeon Kim,Lee, Jiyoun,Shin, Myoungyoup,Hwang, Jaemin,Cho, Sookhyun,Choi, Yeon-Sil,Choi, Hyun-Kyung,Kim, Sung-Eun,Suh, Young-Ger,Lee, Yong-Sil,Kim, Young-Ho,Ha, Hee-Jin,Toth, Attila,Pearce, Larry V.,Tran, Richard,Szabo, Tamas,Welter, Jacqueline D.,Lundberg, Daniel J.,Wang, Yun,Lazar, Jozsef,Pavlyukovets, Vladimir A.,Morgan, Matthew A.,Blumberg, Peter M.
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p. 4143 - 4150
(2007/10/03)
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- KINETICS AND MECHANISM OF HYDROGENATION OF NITROBENZENE BY SYSTEM
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The initial rate of nitrobenzene hydrogenation catalyzed homogenously by cobaloximes is second order in cobalt and is inhibited by an excess of nitrobenzene.It also strongly depends upon cobaloxime:amino ratio.These observations were rationalized in terms of binuclear nitrobenzene-complexed intermediate as crucial in the catalytic cycle.This assumption was further supported by the unusual selectivity of cobaloxime systems, which does not catalyze hydrogenation of ortho-substituted nitrobenzenes.
- Tyrlik, Stanislaw,Kwiecinski, Michal,Kawczynski, Lech
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p. 1947 - 1957
(2007/10/02)
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- Carbazole methyl malonates
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A process for the preparation of α-methyl-carbazole-2-acetic acids, which comprises reacting an α-methyl-3-oxocyclohexane malonic acid di-lower alkyl ester with a substituted phenylhydrazine, and thereafter sequentially oxidizing and hydrolyzing the reaction product to obtain the desired acid, is described.
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- Process for producing 3-anilino-5-pyrazolones
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A process for producing a 3-anilino-5-pyrazolone which comprises reacting a β-anilino-β-alkoxy-acrylate with a hydrazine in the presence of a compound having a pKa of about 8 up to about 14.
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