- Magnetically nano core–shell Fe3O4@Cu(OH)x: a highly efficient and reusable catalyst for rapid and green reduction of nitro compounds
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Magnetically separable nano core–shell Fe3O4@Cu(OH)x with 22?% Cu content was prepared by the addition of sodium hydroxide to a mixture of CuCl2·2H2O and nano Fe3O4 in water. Characterization of the impregnated copper hydroxide was carried out by X-ray fluorescence (XRF), X-ray diffraction (XRD) atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), value stream mapping (VSM) and Brunauer–Emmett–Teller (BET) analysis. The core–shell nanocatalyst exhibited the excellent catalytic activity toward reduction of various nitro compounds to the corresponding amines with NaBH4. All reactions were carried out in H2O (55–60?°C) within 3–15?min to afford amines in high to excellent yields. Reusability of core–shell Cu(OH)x catalyst was examined 9?times without significant loss of its catalytic activity.
- Shokri, Zahra,Zeynizadeh, Behzad,Hosseini, Seyed Ali,Azizi, Behrooz
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- Arenesulfonic acid-functionalized mesoporous silica decorated with titania: A heterogeneous catalyst for the one-pot photocatalytic synthesis of quinolines from nitroaromatic compounds and alcohols
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Acid-modified mesoporous SiO2 decorated with TiO2 (T-S-ArSO3H) was successfully prepared via the co-condensation of 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane (CSPTMS) and tetraethyl orthosilicate in the presence of commercially available Sachtleben Hombikat UV100 TiO2 particles. The resulting bifunctional catalyst induced the efficient one-pot photocatalytic conversion of nitroaromatic compounds into polyalkylated quinolines in O2-free alcoholic solutions. In this process, a simultaneous reduction of the nitro compound and an oxidation of the alcohol are induced by the photogenerated electrons and holes, respectively. An imine is then produced upon condensation of the generated aldehyde and amino compounds. The cyclization of the produced imine yielding polyalkylated quinoline was found to be catalyzed by the surface attached arene-SO 3H group. The newly synthesized catalyst was characterized by TEM and BET measurements, by FTIR, TGA, as well as by an acid-base titration method.
- Hakki, Amer,Dillert, Ralf,Bahnemann, Detlef W.
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- Simple and Practical Synthesis of Various New Nickel Boride-Based Nanocomposites and their Applications for the Green and Expeditious Reduction of Nitroarenes to Arylamines under Wet-Solvent-Free Mechanochemical Grinding
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In this paper, we report a simple synthesis of four new nickel boride-based nanocomposites, namely Ni2B@ZrCl4, Ni2B@Cu2O, Ni2B@CuCl2 and Ni2B@FeCl3, from commercially available and cheap starting materials. All of the new Ni2B-based nanocomposites were well characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Further, the catalytic applications of these new nanocomposites were successfully evaluated in the wet-solvent-free reduction of aromatic nitro compounds to arylamines with sodium borohydride (NaBH4) at room temperature by a mechanochemical grinding technique. All the introduced catalytic systems provide excellent yields of arylamines in very short reaction times for a wide range of substrates. Also, recoverability and reusability of the new nanocomposites were investigated.
- Mousavi, Hossein,Zeynizadeh, Behzad,Younesi, Reza,Esmati, Mozhgan
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- Stable and reusable platinum nanocatalyst: An efficient chemoselective reduction of nitroarenes in water
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Binaphthyl stabilized Pt nanoparticles (Pt-BNP) have been synthesized, characterized, and utilized as an efficient heterogeneous catalyst for chemoselective reduction of nitroarenes at room temperature in water. Several sensitive functional groups like ketone, ester, acid, amide, halides, and nitrile were well tolerated in this chemoselective reduction. The Pt-BNP catalyst was quantitatively recovered without any major change in particle size and reactivity and then efficiently reused for five catalytic cycles.
- Kotha, Surya Srinivas,Sharma, Nidhi,Sekar, Govindasamy
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- Half-sandwich ruthenium complexes with Schiff base ligands bearing a hydroxyl group: Preparation, characterization and catalytic activities
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Three half-sandwich ruthenium(II) complexes with hydroxyl group functionalized Schiff-base ligands [Ru(p-cymene)LCl] (2a-2c) have been synthesized and characterized. All ruthenium complexes were fully characterized by 1H and 13C NMR spectra, mass spectrometry and infrared spectrometry. The molecular structure of ruthenium complex 2c was confirmed by single-crystal X-ray diffraction methods. Furthermore, these half-sandwich ruthenium complexes were found to exhibit high catalytic activity for nitro compounds reduction using NaBH4 reducing agent in the presence of cetyltrimethylammonium bromide (CTAB) in water at room temperature.
- Jia, Wei-Guo,Wang, Zhi-Bao,Zhi, Xue-Ting
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- Quinolone-Hydroxyquinoline Tautomerism in Quinolone 3-Esters. Preserving the 4-Oxoquinoline Structure To Retain Antimalarial Activity
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Recent publications report in vitro activity of quinolone 3-esters against the bc1 protein complex of Plasmodium falciparum and the parasite. Docking studies performed in silico at the yeast Qo site established a key role for the 4-o
- Horta, Pedro,Ku, Nihal,Henriques, Marta Sofia C.,Paixo, Jos A.,Coelho, Lis,Nogueira, Ftima,O'Neill, Paul M.,Fausto, Rui,Cristiano, Maria Lurdes Santos
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- Synthesis, characterization and catalytic activity of gold complexes with pyridine-based selone ligands
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Three neutral pyridine-based selone compounds, 2,6-bis(1-methylimidazole-2-selone)pyridine (Bmsp), 2,6-bis(1-ethylimidazole-2-selone)pyridine (Besp) and 2,6-bis(1-isopropylimidazole- 2-selone)pyridine (Bpsp) have been synthesized and characterized. Reactions of HAuCl4 with pyridine-based selone ligands result in the formation of the complexes [Au(L)Cl2]+[AuCl2]- (L = Bmsp (1); L = Besp (2) and L = Bpsp (3)), respectively. All compounds have been characterized by elemental analysis, NMR IR spectra and electrospray ionization mass spectroscopic (ESI-MS). The molecular structure of 2 has been determined by X-ray crystallography. Moreover, the gold complexes are efficiently catalyzed nitroarenes reduction to aromatic amines in the presence of sodium tetrahydroborate reducing agent in water.
- Zhang, Hai-Ning,Jia, Wei-Guo,Xu, Qiu-Tong,Ji, Chang-Chun
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- Reduction of aromatic nitro compounds to amines using zinc and aqueous chelating ethers: Mild and efficient method for zinc activation
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A mild, environmentally friendly method for reduction of aromatic nitro group to amine is reported, using zinc powder in aqueous solutions of chelating ethers. The donor ether acts as a ligand and also serves as a co-solvent. Water is the proton source. This procedure is also a new method for the activation of zinc for electron transfer reduction of aromatic nitro compounds. The reduction is accomplished in a neutral medium and other reducing groups remained unaffected. The ethers used are dioxolane, 1,4-dioxane, ethoxymethoxyethane, dimethoxymethane, 1,2-dimethoxyethane, and diglyme.
- Kumar, Pookot Sunil,Lokanatha Rai, Kuriya M.
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- Palladium Immobilized on a Polyimide Covalent Organic Framework: An Efficient and Recyclable Heterogeneous Catalyst for the Suzuki–Miyaura Coupling Reaction and Nitroarene Reduction in Water
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An efficient and recyclable Pd nano-catalyst was developed via immobilization of Pd nanoparticles on polyimide linked covalent organic frameworks (PCOFs) that was facilely prepared through condensation of melamine and 3,3′,4,4′-biphenyltetracarboxylic dianhydride. The Pd nanoparticles (Pd NPs) catalyst was thoroughly characterized by FT-IR, XRD, SEM, TEM. Furthermore, the catalytic activity of Pd NPs catalyst was evaluated by Suzuki–Miyaura coupling reaction and nitroarene reduction in water, respectively. The excellent yields of corresponding products revealing revealed that the Pd NPs catalyst could be applied as an efficient and reusable heterogeneous catalyst for above two reactions. Graphical Abstract: [Figure not available: see fulltext.]
- Dong, Zhenhua,Pan, Hongguo,Gao, Pengwei,Xiao, Yongmei,Fan, Lulu,Chen, Jing,Wang, Wentao
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p. 299 - 306
(2021/05/10)
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- Selective Encapsulation and Unusual Stabilization of cis-Isomers by a Spherical Polyaromatic Cavity
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To explore new cavity functions, we herein employed cis-trans stereoisomers with a N=N, C=C, or C=N unit as guest indicators for a polyaromatic capsule. Thanks to the rigid, spherical cavity with a diameter of ～1 nm, azobenzene and stilbene derivatives ar
- Yuasa, Mana,Sumida, Ryuki,Tanaka, Yuya,Yoshizawa, Michito
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supporting information
(2022/02/02)
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- Cu-Catalyzed Cross-Coupling of Nitroarenes with Aryl Boronic Acids to Construct Diarylamines
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The development and study of a simple copper-catalyzed reaction of nitroarenes with aryl boronic acids to form diarylamines that uses phenyl silane as the stoichiometric terminal reductant is described. This cross-coupling reaction requires as little as 2 mol % of CuX and 4 mol % of diphosphine for success and tolerates a broad range of functional groups on either the nitroarene or the aryl boronic acid to afford the amine in good yield. Mechanistic investigations established that the cross-coupling reaction proceeds via a nitrosoarene intermediate and that copper is required to catalyze both the deoxygenation of the nitroarene to afford the nitrosoarene and C-NAr bond formation of the nitrosoarene with the aryl boronic acid.
- Guan, Xinyu,Zhu, Haoran,Driver, Tom G.
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p. 12417 - 12422
(2021/10/12)
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- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- Rhodium nanoparticles supported on 2-(aminomethyl)phenols-modified Fe3O4 spheres as a magnetically recoverable catalyst for reduction of nitroarenes and the degradation of dyes in water
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A magnetic nanostructured catalyst (Fe3O4@SiO2-Amp-Rh) modified with 2-(aminomethyl)phenols (Amp) was designed and prepared, which is used to catalyze the reduction of aromatic nitro compounds into corresponding amines and the degradation of dyes. The 2-aminomethylphenol motif plays a vital role in the immobilization of rhodium nanoparticles to offer extraordinary stability, which has been characterized by using various techniques, including transmission electron microscopy (TEM), thermal gravimetric analyzer (TGA), X-Ray Diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). A variety of nitroaromatic derivatives have been reduced to the corresponding anilines in water with up to yields of 99% within 1?h at room temperature. In addition, the catalyst system is effective in catalyzing the reduction of toxic pollutant 4-nitrophenol and the degradation of MO, MB and RhB dyes. Importantly, this catalyst Fe3O4@SiO2-Amp-Rh can be easily recovered by an external magnetic field because of the presence of magnetic core of Fe3O4, and the activity of Fe3O4@SiO2-Amp-Rh does not decrease significantly after 7 times’ recycling, which indicates that the catalyst performed high reactivity as well as stability. Graphical abstract: [Figure not available: see fulltext.]
- Chen, Tian,Chen, Zhangpei,Hu, Jianshe,Lv, Kexin,Reheman, Aikebaier,Wang, Gongshu
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- Magnetically‐recoverable Schiff base complex of Pd(II) immobilized on Fe3O4@SiO2 nanoparticles: an efficient catalyst for the reduction of aromatic nitro compounds to aniline derivatives
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Fe3O4@SiO2/Schiff base/Pd(II) is reported as a magnetically recoverable heterogeneous catalyst for the chemoselective reduction of aromatic nitro compounds to the corresponding amines through catalytic transfer hydrogenation (CTH). In this regard, a small amount of the nanocatalyst (0.52?mol% Pd) and hydrazine hydrate, showing safe characteristics and perfect ability as the hydrogen donor, were added to the nitro substrates. The experiments described the successful reduction of aromatic nitro compounds with good to excellent yields and short reaction times. The catalyst, due to its magnetic property, could be simply separated from the reaction mixture by a permanent magnet and reused in seven consecutive reactions without considerable loss in its activity. Moreover, the leaching of Pd was only 3.6% after the seventh run. Thus, the most striking feature of this method is to use a small amount of the magnetic nanocatalyst along with a cheap and safe hydrogen source to produce the important amine substances selectively, which makes the method economical, cheap, environmentally friendly, and simple. Graphic abstract: [Figure not available: see fulltext.]
- Azadi, Sedigheh,Esmaeilpour, Mohsen,Sardarian, Ali Reza
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p. 809 - 821
(2021/07/20)
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- Highly efficient hydrogenation reduction of aromatic nitro compounds using MOF derivative Co-N/C catalyst
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The direct hydrogenation reduction of aromatic nitro compounds to aromatic amines with non-noble metals is an attractive area. Herein, the pyrolysis of Co(2-methylimidazole)2 metal-organic framework successfully produces a magnetic Co-N/C nanocomposite, which exhibits a porous structure with a high specific area and uniform Co nanoparticle distribution in nitrogen-doped graphite. In addition, the Co-N/C catalysts possess high cobalt content (23%) with highly active β-Co as the main existing form and high nitrogen content (3%). These interesting characteristics endow the Co-N/C nanocomposite with excellent catalytic activity for the hydrogenation reduction of nitro compounds under mild conditions. In addition, the obtained Co-N/C nanocomposites possess a broad substrate scope and good cycle stability for the reduction of halogen-substituted or carbonyl substituted phenyl nitrates. This journal is
- Dai, Yuyu,Li, Xiaoqing,Wang, Likai,Xu, Xiangsheng
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p. 22908 - 22914
(2021/12/24)
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- Selective Reduction of Nitroarenes to Arylamines by the Cooperative Action of Methylhydrazine and a Tris(N-heterocyclic thioamidate) Cobalt(III) Complex
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We report an efficient catalytic protocol that chemoselectively reduces nitroarenes to arylamines, by using methylhydrazine as a reducing agent in combination with the easily synthesized and robust catalyst tris(N-heterocyclic thioamidate) Co(III) complex [Co(κS,N-tfmp2S)3], tfmp2S = 4-(trifluoromethyl)-pyrimidine-2-thiolate. A series of arylamines and heterocyclic amines were formed in excellent yields and chemoselectivity. High conversion yields of nitroarenes into the corresponding amines were observed by using polar protic solvents, such as MeOH and iPrOH. Among several hydrogen donors that were examined, methylhydrazine demonstrated the best performance. Preliminary mechanistic investigations, supported by UV-vis and NMR spectroscopy, cyclic voltammetry, and high-resolution mass spectrometry, suggest a cooperative action of methylhydrazine and [Co(κS,N-tfmp2S)3] via a coordination activation pathway that leads to the formation of a reduced cobalt species, responsible for the catalytic transformation. In general, the corresponding N-arylhydroxylamines were identified as the sole intermediates. Nevertheless, the corresponding nitrosoarenes can also be formed as intermediates, which, however, are rapidly transformed into the desired arylamines in the presence of methylhydrazine through a noncatalytic path. On the basis of the observed high chemoselectivity and yields, and the fast and clean reaction processes, the present catalytic system [Co(κS,N-tfmp2S)3]/MeNHNH2 shows promise for the efficient synthesis of aromatic amines that could find various industrial applications.
- Ioannou, Dimitris I.,Gioftsidou, Dimitra K.,Tsina, Vasiliki E.,Kallitsakis, Michael G.,Hatzidimitriou, Antonios G.,Terzidis, Michael A.,Angaridis, Panagiotis A.,Lykakis, Ioannis N.
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p. 2895 - 2906
(2021/02/27)
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- Synthesis, Structure, and Catalytic Hydrogenation Activity of [NO]-Chelate Half-Sandwich Iridium Complexes with Schiff Base Ligands
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A series of N,O-coordinate iridium(III) complexes with a half-sandwich motif bearing Schiff base ligands for catalytic hydrogenation of nitro and carbonyl substrates have been synthesized. All iridium complexes showed efficient catalytic activity for the hydrogenation of ketones, aldehydes, and nitro-containing compounds using clean H2 as reducing reagent. The iridium catalyst displayed the highest TON values of 960 and 950 in the hydrogenation of carbonyl and nitro substrates, respectively. Various types of substrates with different substituted groups afforded corresponding products in excellent yields. All N,O-coordinate iridium(III) complexes 1-4 were well characterized by IR, NMR, HRMS, and elemental analysis. The molecular structure of complex 1 was further characterized by single-crystal X-ray determination.
- Lv, Wen-Rui,Li, Rong-Jian,Liu, Zhen-Jiang,Jin, Yan,Yao, Zi-Jian
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p. 8181 - 8188
(2021/05/26)
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- Rhodium-terpyridine Catalyzed Transfer Hydrogenation of Aromatic Nitro Compounds in Water
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A rhodium terpyridine complex catalyzed transfer hydrogenation of nitroarenes to anilines with i-PrOH as hydrogen source and water as solvent has been developed. The catalytic system can work at a substrate/catalyst (S/C) ratio of 2000, with a turnover frequency (TOF) up to 3360 h?1, which represents one of the most active catalytic transfer hydrogenation systems for nitroarene reduction. The catalytic system is operationally simple and the protocol could be scaled up to 20 gram scale. The water-soluble catalyst bearing a carboxyl group could be recycled 15 times without significant loss of activity.
- Liu, Yuxuan,Miao, Wang,Tang, Weijun,Xue, Dong,Xiao, Jianliang,Wang, Chao,Li, Changzhi
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supporting information
p. 1725 - 1729
(2021/06/01)
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- Selective Carbon-Carbon Bond Amination with Redox-Active Aminating Reagents: A Direct Approach to Anilines?
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Amines are among the most fundamental motifs in chemical synthesis, and the introduction of amine building blocks via selective C—C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification. Herein, we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents, which are easily prepared from hydroxylamine. Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions. Good compatibility and valuable applications of the transformation were also displayed.
- Qiu, Xu,Wang, Yachong,Su, Lingyu,Jin, Rui,Song, Song,Qin, Qixue,Li, Junhua,Zong, Baoning,Jiao, Ning
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p. 3011 - 3016
(2021/09/13)
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- Method for synthesizing heteroatom- substituted aromatic compound from styrene compound
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The invention discloses a method for synthesizing a heteroatom-substituted aromatic compound from a styrene compound, which comprises the following steps of: mixing a styrene compound with a general formula (I) and a heteroatom-containing compound with a general formula (II), and reacting in the presence of an acid additive and an organic solvent to obtain a heteroatom-substituted compound with ageneral formula (III). According to the synthesis method disclosed by the invention, a large amount of styrene compounds are used as raw materials and react to generate aromatic amine or phenol compounds under the action of no metal catalysis; and compared with the traditional aromatic amine and phenol synthesis method, the method has the advantages of high yield, simple conditions, low waste discharge amount, no metal participation, simple reaction equipment, easiness in industrial production and the like.
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Paragraph 0201-0204
(2021/02/06)
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- Synthesis of Substituted Anilines from Cyclohexanones Using Pd/C-Ethylene System and Its Application to Indole Synthesis
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The synthesis of anilines and indoles from cyclohexanones using a Pd/C-ethylene system is reported. A simple combination of NH4OAc and K2CO3 under nonaerobic conditions was found to be the most suitable to perform this reaction. Hydrogen transfer between cyclohexanone and ethylene generates the desired products. The reaction tolerates a variety of substitutions on the starting cyclohexanones.
- Maeda, Katsumi,Matsubara, Ryosuke,Hayashi, Masahiko
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supporting information
p. 1530 - 1534
(2021/03/08)
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- Selective primary aniline synthesis through supported Pd-catalyzed acceptorless dehydrogenative aromatization by utilizing hydrazine
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By utilizing hydrazine (N2H4) as the nitrogen source in the presence of a hydroxyapatite-supported Pd nanoparticle catalyst (Pd/HAP), various primary anilines can be selectively synthesized from cyclohexanonesviaacceptorless dehydrogenative aromatization. The strong nucleophilicity of N2H4and the stability of the hydrazone intermediates can effectively suppress the formation of the undesired secondary aniline byproducts.
- Lin, Wei-Chen,Yamaguchi, Kazuya,Yatabe, Takafumi
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supporting information
p. 6530 - 6533
(2021/07/07)
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- Shape-dependent reactivity and chemoselectivity of nanogold towards nitrophenol reduction in water
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Although the catalytic activity of nano-gold surfaces for the reduction of nitro compounds has been known, the effect of their shape has been rarely evaluated. Here, the synthesis, characterization, and application of both gold nanoworms (GNW) and gold nanospheres (GNS) are described. Both GNW and GNS were characterized using SEM, TEM, UV–Vis, FTIR, and XPS spectroscopy. The catalytic efficiency of GNW with an average dimensions of 2 × 250 nm (D × L) towards the hydrogenation of nitrophenol, a pollutant present in industrial wastewater, is higher (TOF 3675 h?1) than that of spherical GNS (10 ± 1 nm), for which TOF is 1838 h?1 in water using NaBH4 as the reductant. The selectivity of 4-aminophenol is 100% for both GNS and GNW.
- Aziz, Md Abdul,Nafiu, Sodiq Adeyeye,Shaikh, M. Nasiruzzaman
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- Ultrasound-assisted rapid reduction of nitroaromatics to anilines using gallium metal
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The reduction of nitroaromatic compounds to anilines is widely used throughout organic synthesis. Typical methods of performing this transformation utilize hydrogenation over a pyrophoric catalyst or a finely divided reducing metal, which often affords heterogeneous mixtures that are difficult to purify. Herein, we report for the first time the use of gallium metal as a reducing agent in organic synthesis. The reaction proceeds under aerobic conditions and affords homogeneous mixtures for a convenient workup. Using this method, twelve anilines were obtained in 33% to quantitative yields with short reaction times of 10-60 minutes.
- Bento, Ian,Bernaldez, Mabel,Noguchi, Ryden,Kawakami, Joel
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supporting information
p. 1404 - 1407
(2020/03/31)
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- Copper(II) complex with oxazoline ligand: Synthesis, structures and catalytic activity for nitro compounds reduction
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The Cu(II) complexes bearing bisoxazolines, tridentate pincer pybox and terpyridine ligands have been synthesized and fully characterized. The molecular structures of copper complexes 1a and 1c were confirmed by single-crystal X-ray diffraction methods. These copper complexes highly catalyzed nitro compounds reduction to aniline and its derivatives in the presence of NaBH4 reducing agent in water solvent. The complex 1e was an efficient catalyst toward nitro compounds reduction with wide functional group substrate scope and aliphatic nitro compounds.
- Du, Jun,Gao, Li-Li,Jia, Wei-Guo,Li, Mei,Zhi, Xue-Ting
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- Synthesis, characterization, and catalytic activity of half-sandwich ruthenium complexes with pyridine/phenylene bridged NHC = E (NHC = N-heterocyclic carbene, E = S, Se) ligands
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Three half-sandwichruthenium(II) complexes with pyridine/phenylene bridged NHC = E (NHC = N-heterocyclic carbene, E = S, Se) ligands [Ru(p-cymene)L](PF6)1–2 (1a–1c, L = ligand) were synthesized and characterized. All ruthenium complexes were fully characterized by 1H and 13C NMR spectra, mass spectrometry, and single-crystalX-ray diffraction methods. Moreover, the half-sandwich ruthenium complexes with NHC = E ligands showed highly catalytic activities towards to the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of R–NO2 to R–NH2 at 353 K in water.
- Jia, Wei-Guo,Du, Teng-Teng,Gao, Li-Li,Du, Jun
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- Palladium supported on metal–organic framework as a catalyst for the hydrogenation of nitroarenes under mild conditions
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Sustainable development demands an environmentally friendly and efficient method for the hydrogenation of organic molecules, including the hydrogenation of functionalized nitroarenes. In this study, a highly active and selective metal–organic framework-supported palladium catalyst was prepared for the catalytic hydrogenation of nitroarenes. High selectivity (>99%) and excellent yield (98%) of aniline were realized after 2 hours in ethanol under hydrogen (1 atm) at room temperature. The reductions were successfully carried out in the presence of a wide range of other reducible functional groups. More importantly, the catalyst was very stable without the loss of its catalytic activity after five cycles.
- Bao, Lingxiang,Fei, Teng,Li, Jiazhe,Pang, Siping,Sun, Chenghui,Yan, Zhiyuan,Yu, Zongbao
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- Immobilization of Au nanoparticles on poly(glycidyl methacrylate)-functionalized magnetic nanoparticles for enhanced catalytic application in the reduction of nitroarenes and Suzuki reaction
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We report a novel strategy for the synthesis of magnetic nanocomposite for highly efficient catalysis. Poly(glycidyl methacrylate) (PGMA) chains were grafted to the surface of magnetic nanoparticles (MNPs) through surface-initiated reversible addition-fragmentation chain transfer polymerization. Then, the oxirane rings in the PGMA chains were opened with 2,6-diamino pyridine (DAP) molecules as ligands to prepare the solid support. Finally, this magnetic nanocomposite was used for the immobilization of gold nanoparticles. Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, gel permeation chromatography, vibrating sample magnetometry, and atomic absorption spectroscopy were used for characterization of the catalyst. The loading of gold nanoparticles on the solid support was 0.52 mmol/g. The catalytic activity of the prepared catalyst (MNP@PGMA@DAP@Au) was evaluated for the reduction of nitro compounds and C–C coupling reaction in water. The catalyst can be easily recovered and reused seven times without significant loss of catalytic activity.
- Pourjavadi, Ali,Kohestanian, Mohammad,Keshavarzi, Nahid
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- Tin(ii) chloride dihydrate/choline chloride deep eutectic solvent: Redox properties in the fast synthesis of: N -arylacetamides and indolo(pyrrolo)[1,2- a] quinoxalines
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In this contribution a physicochemical, IR and Raman characterization for the tin(ii) chloride dihydrate/choline chloride eutectic mixture is reported. The redox properties of this solvent were also studied by cyclic voltammetry finding that it can be successfully used as an electrochemical solvent for electrosynthesis and electroanalytical processes and does not require negative potentials as verified by the reduction of nitrobenzene. The potential use of this eutectic mixture as a redox solvent was further explored in obtaining aromatic amines and N-arylacetamides starting from a wide variety of nitroaromatic compounds. In addition, a fast synthetic strategy for the construction of a series of indolo(pyrrolo)[1,2-a]quinoxalines was developed by reacting 1-(2-nitrophenyl)-1H-indole(pyrrole) with aldehydes. This simple protocol offers a straightforward method for the construction of the target quinoxalines in short reaction times and high yields where the key step involves a tandem one-pot reductive cyclization-oxidation.
- Bejarano, Oscar Rodríguez,Ochoa-Puentes, Cristian,Pe?a-Solórzano, Diana,Trujillo, Sergio Alfonso
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p. 40552 - 40561
(2020/11/18)
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- Pd Nanoparticles Assembled on Metalporphyrin-Based Microporous Organic Polymer as Efficient Catalyst for Tandem Dehydrogenation of Ammonia Borane and Hydrogenation of Nitro Compounds
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Abstract: Metalporphyrin-based porous polymers supporting high dispersed Pd nanoparticle (NP) catalysts (HUST-1-Pd) were prepared with a novel solvent-knitting hyper-crosslinked polymer method using 5-, 10-, 15-, and 20-tetraphenylporphyrin (TPP) as building blocks. The N2 sorption isotherms of the catalysts show that the HUST-1-Pd possesses many ultra-micropores and continuous mesopores. The NPs are assembled on tetraphenylporphyrin structures and show Pd-N4 composition-dependent catalysis for methanolysis of ammonia borane (AB) and hydrogenation of aromatic nitro compounds to primary amines in methanol solutions at room temperature. The nano-palladium reduced by NaBH4 has efficient catalytic activity for AB methanolysis. A variety of R-NO2 derivatives were reduced selectively into R-NH2 via palladium catalyzed tandem reactions with 5–30?min of reaction time with conversion yields reaching up to 90%. The derivatives also give excellent recycling performance (more than 10 times). Furthermore, the turnover frequency (TOF) can reach 87,209?h?1. The HUST-1-Pd compounds represent a unique metal catalyst for hydrogenation reactions in a green environment without using pure hydrogen. Graphic Abstract: A monodisperse Pd NPs embed in porphyrin-based microporous organic polymer was reported to catalyse the tandem dehydrogenation of ammonia borane and hydrogenation of R-NO2 to R-NH2 at room temperature. The catalyst is efficient and reusable in an environment-friendly process with short reaction times and high yields.[Figure not available: see fulltext.]
- Zou, Zhijuan,Jiang, Yaya,Song, Kunpeng
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p. 1277 - 1286
(2019/11/20)
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- Commercially Available CuO Catalyzed Hydrogenation of Nitroarenes Using Ammonia Borane as a Hydrogen Source
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Tandem ammonia borane dehydrogenation and nitroarenes hydrogenation has been reported as a novel strategy for the preparation of aromatic amines. However, the practical application of this strategy is subjected to the high-cost and tedious preparation of supported noble metal nanocatalysts. The commercially available CuO powder is herein demonstrated to be a robust catalyst for hydrogenation of nitroarenes using ammonia borane as a hydrogen source under mild conditions. Numerous amines (even sterically hindered, halogenated, and diamines) could be obtained through this method. This monometallic catalyst is characteristic of support-free, excellent chemoselectivity, low-cost, and high recyclability, which will favor its future utilization in preparative reduction chemistry. Mechanistic studies are also carried out to clarify that diazene and azoxybenzene are key intermediates of this heterogeneous reduction.
- Du, Jialei,Chen, Jie,Xia, Hehuan,Zhao, Yiwei,Wang, Fang,Liu, Hong,Zhou, Weijia,Wang, Bin
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p. 2426 - 2430
(2020/03/30)
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- Method for preparing amino compound by catalytically reducing nitro compound with alkaline earth metal hydride
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The invention relates to a method for preparing an amino compound by catalytically reducing a nitro compound with alkaline earth metal hydride, and belongs to the technical field of organic synthesis.The method comprises the following steps: by taking a nitro compound as a reaction substrate, alkaline earth metal hydride as a hydrogen source and diborate as a catalyst, respectively adding the nitro compound, the alkaline earth metal hydride and the diborate into an organic solvent, stirring and heating to react for 3-20 hours at the reaction temperature of 50-150 DEG C; and after the reactionis finished, separating and purifying the reaction mother liquor to obtain the amino compound. The method has the advantages of simple synthesis steps, mild reaction conditions, avoiding of the use of high pressure hydrogen, no participation of transition metals in the reaction process, reduction of the reaction cost, greenness, environmental protection, and reduction of the environmental pollution.
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Paragraph 0048-0053
(2020/09/16)
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- Tuneable Copper Catalysed Transfer Hydrogenation of Nitrobenzenes to Aniline or Azo Derivatives
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A highly versatile and flexible copper nanoparticle (Cu(0) NPs) catalytic system has been developed for the controlled and selective transfer hydrogenation of nitroarene. Interestingly, the final catalytic product is strongly dependent on the nature of the hydrogen donor source. The yield of nitrobenzene reduction to aniline increased from 20% to an almost quantitative yield over a range of alcohols, diols and aminoalcohols. In glycerol at 130 °C aniline was isolated in 93% yield. In ethanolamine, the reaction was conveniently performed at a lower temperature (55 °C) and gave selectively substituted azobenzene (92% yield). Experimental studies provide support for a reaction pathway in which the Cu(0) NPs catalysed transfer hydrogenation of nitrobenzene to aniline proceeds via the condensation route. The high chemoselectivity of both protocols has been proved in experiments on a panel of variously substituted nitroarenes. Enabling technologies, microwaves and ultrasound, used both separately and in combination, have successfully increased the reaction rate and reaction yield. (Figure presented.).
- Moran, Maria Jesus,Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Manzoli, Maela,Cravotto, Giancarlo
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supporting information
p. 2689 - 2700
(2020/05/18)
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- Solvent-free synthesis of propargylamines via A3 coupling reaction and organic pollutant degradation in aqueous condition using Cu/C catalyst
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The present report focuses on the efficient and operationally simple synthesis of biomass-derived carbon as support to immobilize copper particles as a catalyst for the one-pot synthesis of propargylamines from furfural via the A3 coupling reaction. This new catalyst showed remarkable catalytic performance leading to a 97% yield within 5 h at 80 °C using 5 mg (0.0022 mmol Cu) of Cu/C catalyst under solvent-free condition. Moreover, nitro-substituted compounds such as 4-nitrophenol (4-NP) are highly toxic and not easily degradable. Hence, a quick and effective method is required to neutralize these toxic compounds. The synthesized active support Cu/C catalyst having various electron-donating groups containing small amounts of Cu plays an essential role in the catalytic reduction of 4-NP (0.1 g). Using only 3 mg (0.0013 mmol Cu) of Cu/C catalyst and NaBH4 (10 mmol), a 99% yield (100% selectivity) in the aqueous condition at 25 °C was achieved. The catalytic reduction follows the pseudo-first-order kinetics with reaction rate constant of 0.028 s?1. Moreover, results demonstrate that the Cu/C catalyst has superior catalytic activity due to the presence of electron-donating molecules such as O, S, and N atoms, which enable synergistic effect in enhancing the overall catalytic performance. Notably, the recoverability and recyclability of the synthesized catalyst were evaluated for up to four cycles, which confirmed its stability in these cycles.
- Rathod, Pramod V.,Puguan, John Marc C.,Kim, Hern
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- The immobilized Cu nanoparticles on magnetic montmorillonite (MMT?Fe3O4?Cu): As an efficient and reusable nanocatalyst for reduction and reductive-acetylation of nitroarenes with NaBH4
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In this study, the immobilization of copper nanoparticles on superparamagnetic montmorillonite, MMT?Fe3O4?Cu, was studied. Magnetically nanoparticles (MNPs) of iron oxide (Fe3O4) were primarily prepared by a chemical co-precipitation method. Next, the prepared Fe3O4 MNPs were intercalated within the interlamellar spaces and external surface of sodium-exchanged montmorillonite. Finally, Cu NPs were immobilized on magnetic montmorillonite by a simply mixing of an aqueous solution of CuCl2·2H2O with MMT?Fe3O4 followed by the reduction with NaBH4. Characterization of MMT?Fe3O4 clay system represented that through the immobilization of Fe3O4 MNPs, disordered-layers structure of MMT was easily reorganized to an ordered-layers arrangement. The synthesized composite systems were characterized using FT-IR, SEM, EDX, XRD, VSM, BET and ICP-OES analyses. SEM analysis exhibited that dispersion of Cu NPs, with the size distribution of 15–25 nm, on the surface of magnetic clay was taken place perfectly. BET surface analysis indicated that after the immobilization of Fe3O4 and Cu species, the surface area and total pore volume of MMT?Fe3O4?Cu system was decreased. Next, the Cu-clay nanocomposite system showed a perfect catalytic activity towards reduction of nitroarenes to anilines as well as reductive-acetylation of nitroarenes to acetanilides using NaBH4 and Ac2O in water as a green and economic solvent. The copper magnetic clay catalyst can be easily separated from the reaction mixture by an external magnetic field and reused for six consecutive cycles without the significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Rahmani, Soleiman,Tizhoush, Hengameh
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- Acceptorless dehydrogenative oxidation of primary alcohols to carboxylic acids and reduction of nitroarenes via hydrogen borrowing catalyzed by a novel nanomagnetic silver catalyst
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A novel silver nano magnetic catalyst was devised for dehydrogenative oxidation of aromatic and aliphatic alcohols to the corresponding acid with water as the sole oxygen source and hydrogen gas as the only by-product. The designed catalytic system advantages from easy recovery of magnetic materials i.e. magnetic decantation, being economically viable and environmentally friendly. Furthermore, the catalytic reaction is able to reduce aryl nitro compounds in the absence of any reducing agent.
- Yazdani, Elahe,Heydari, Akbar
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supporting information
(2020/08/14)
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- EffectiveN-methylation of nitroarenes with methanol catalyzed by a functionalized NHC-based iridium catalyst: a green approach toN-methyl amines
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Compound [IrBr(CO)2(κC-tBuImCH2PyCH2OMe)] featuring a flexible pyridine/OMe functionalized NHC ligand κ1C coordinated efficiently catalyzes the selectiveN-monomethylation of nitroarenes using methanol as both the reducing agent and the C1 source. A range of functionalized nitroarenes including heterocyclic or sterically hindered derivatives have been efficiently converted to the correspondingN-monomethyl amines in good yields at low catalyst loadings using sub-stoichiometric amounts of Cs2CO3as a base. Mechanistic investigations support a borrowing-hydrogen mechanism in which methanol acts as the hydrogen source and methylating agent. Further, the hydrogen transfer reduction of nitrobenzene to aniline under optimized reaction conditions should proceed through a direct mechanism involving nitrosobenzene andN-phenylhydroxylamine intermediates.
- González-Lainez, Miguel,Jiménez, M. Victoria,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.
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p. 3458 - 3467
(2020/06/17)
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- A new ligand for copper-catalyzed amination of aryl halides to primary(hetero)aryl amines
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N,N′-Bis(3,5-dimethoxyphenyl)cyclopentane-1,1-dicarboxamide was found as a new ligand for copper-catalyzed amination of aryl iodides, bromides and chlorides to afford various primary (hetero)aryl amines. These reactions proceeded efficiently under mild conditions when inexpensive aqueous ammonia (28% NH3 in H2O) was used as the amino source.
- Chen, Dong,Dong, Xinrui,Jiang, Shang,Jiang, Sheng,Qiu, Yatao,Wu, Xiaoxing
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supporting information
(2020/02/11)
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- Recyclable Pd/C catalyzed one-step reduction of carbonyls to hydrocarbons under simple conditions without extra base
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The reductions of carbonyls for the synthesis of hydrocarbons were developed with hydrazine hydrate, hydrogen gas and ammonium formate respectively. The simple, mild and efficient conditions were provided by employing recyclable Pd/C as catalyst in normal solvents at 100 °C and the reactions proceeded smoothly to produce the corresponding products with good to excellent yields. And gram-scale reactions and recycling of the catalyst were also demonstrated. Furtherly, the mechanism has been proposed.
- Zhou, Xiao-Yu,Chen, Xia
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supporting information
(2019/12/06)
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- Colloid and Nanosized Catalysts in Organic Synthesis: XXI. Reduction of Nitroarenes Catalyzed by Immobilized Nickel Nanoparticles
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It has been found that nickel nanoparticles on NaX zeolite, γ-alumina, activated carbon, or magnesium oxide support catalyze the reduction of nitrobenzene and its homologs affording aniline and its derivatives in high yield. The effect of the substrate on
- Mokhov,Popov, Yu. V.,Nebykov,Nishchik,Shcherbakova,Zotov, Yu. L.
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p. 1549 - 1553
(2019/10/14)
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- Superfine CoNi alloy embedded in Al2O3 nanosheets for efficient tandem catalytic reduction of nitroaromatic compounds by ammonia borane
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Aromatic amino compounds are important and universally used chemical intermediates in a wide range of industrial fields. Thus, their production with high efficiency and selectivity under ambient conditions is expected and demanded in modern industry. Herein, a series of superfine CoNi alloy nanoparticles embedded in Al2O3 nanosheet (CoxNi1-x/Al2O3, where x represents the content of Co in the precursor) catalysts was fabricated from CoNiAl-LDH and used to catalyze the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of nitroaromatics to the corresponding amines. Systematic experiments indicate that the composition, size, morphology and catalytic performance of the CoxNi1-x/Al2O3 catalysts can be easily controlled by changing the content of Ni in the CoNiAl-LDH precursor. Particularly, Co0.67Ni0.33/Al2O3 exhibited the best tandem catalytic performance among the six samples. This as-prepared catalyst not only showed a moderate turn-over-frequency value (TOF: 34.5 molH2 molCo0.67Ni0.33-1 min-1 at 298 K without base or additives) and relatively low activation energy (32.4 kJ mol-1) for the dehydrogenation of AB, but also superior catalytic activity (conversion yield reaching up to 100%) and selectivity (>99%) for the tandem reductive transformation of in excess of sixteen types of nitroaromatics to aromatic amines. Density functional theory (DFT) calculations suggest that the construction of the CoNi alloy optimized the electronic structure with respect to the pure component, promoting its activity for AB hydrolysis and nitroaromatics hydrogenation. Finally, the catalyst could be easily recycled using a magnet due to the magnetic properties of the Co0.67Ni0.33 alloy.
- Cheng, Sihang,Liu, Yanchun,Zhao, Yingnan,Zhao, Xinyu,Lang, Zhongling,Tan, Huaqiao,Qiu, Tianyu,Wang, Yonghui
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p. 17499 - 17506
(2019/12/23)
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- Au@zirconium-phosphonate nanoparticles as an effective catalytic system for the chemoselective and switchable reduction of nitroarenes
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In the present paper, a novel inorganic-organic layered material, a zirconium phosphate aminoethyl phosphonate, ZP(AEP), bearing aminoethyl groups on the layer surface, was used to immobilize AuNPs by a two-step procedure. The gold-based catalyst, Au1@ZP(AEP), containing 1 wt% Au, was characterized in terms of physico-chemical properties and TEM analysis revealed that the AuNPs have a spherical shape and an average size of 7.8 (±2.4) nm. Au1@ZP(AEP) proved its high efficiency for the chemoselective reduction of nitroarenes under mild conditions. Both batch and flow condition protocols have been defined. The catalytic system has been proven to be able to easily switch chemoselectivity allowing the control of the reduction of a series of nitroaromatics towards their corresponding azoxyarenes (2a-k) or anilines (2a-l) in 96% EtOH or abs EtOH, respectively, by using NaBH4 as a reducing agent, in good to excellent yields. Recovery and reuse of the catalytic system has been investigated proving the benefits of the flow approach.
- Ferlin, Francesco,Cappelletti, Matteo,Vivani, Riccardo,Pica, Monica,Piermatti, Oriana,Vaccaro, Luigi
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p. 614 - 626
(2019/02/13)
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- Hydrogenation of Functionalized Nitroarenes Catalyzed by Single-Phase Pyrite FeS2 Nanoparticles on N,S-Codoped Porous Carbon
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Catalytic hydrogenation of nitroarenes is an industrially very important and environmentally friendly process for the production of anilines; however, highly chemoselective reduction of nitroarenes decorated with one or more reducible groups in a nitroarene molecule remains a challenge. Herein, a novel hybrid non-noble iron-based nanocatalyst (named as FeS2/NSC) was developed, which was prepared from biomass as C and N source together with inexpensive Fe(NO3)3 as Fe source through high-temperature pyrolysis in a straightforward and cost-effective procedure. Comprehensive characterization revealed that single-phase pyrite FeS2 nanoparticles with precisely defined composition and uniform size were homogeneously dispersed on N,S-codoped porous carbon with large specific surface area, hierarchical porous channels, and high pore volume. The resultant catalyst FeS2/NSC demonstrated good catalytic activity for hydrogenation of functionalized nitroarenes with good tolerance of various functional groups in water as a sustainable and green solvent. Compared with bulk pyrite FeS2 and other non-noble metal-based heterogeneous catalysts reported in the literature, a remarkably enhanced activity was observed under mild reaction conditions. More importantly, FeS2/NSC displayed exclusive chemoselectivity for the reduction of nitro groups for nitroarenes bearing varying readily reducible groups.
- Duan, Yanan,Dong, Xiaosu,Song, Tao,Wang, Zhaozhan,Xiao, Jianliang,Yuan, Youzhu,Yang, Yong
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- Method for preparing aromatic amine compounds from aromatic nitro compounds by catalytic reduction of nano porous gold catalyst
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The invention discloses a method for preparing aromatic amine compounds from aromatic nitro compounds by catalytic reduction of a nano porous gold catalyst. The nano porous gold catalyst and the aromatic nitro compounds are taken as substrates and subjected to a reaction in methanol with ammonia borane as a hydrogen source at the room temperature, and a product is obtained. The high probability ofagglomeration of conventional granular catalysts is prevented, the nano porous gold catalyst shows excellent structural stability and good recycling efficiency, has excellent universality, especiallyfor the aromatic nitro compounds, and has green and mild catalytic conditions, high yield and good selectivity. The yield of m-nitroaniline from m-nitrotoluene can reach 98%. Moreover, the catalyst can be centrifugally recovered and can be recycled without other treatment, the yield of preparing m-nitroaniline from m-nitrotoluene by catalyzing can still reach 88% after being recycled five times,and thus, waste is effectively avoided. The catalyst shows high activity during the reaction and excellent stability under the reaction conditions.
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Paragraph 0024; 0025
(2019/07/04)
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- Sustainable Protocol for the Reduction of Nitroarenes by Heterogeneous Au@SBA-15 with NaBH4 under Flow Conditions
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A gold-incorporated SBA-15 catalyst was prepared by a solvent-free ball-milling approach. The catalyst showed high reactivity and selectivity in the reduction of a variety of nitroarenes to anilines operating in absolute EtOH with NaBH4 as reducing agent. The catalyst was reused in batch conditions over five consecutive runs without any losses of activity or selectivity. Considering the high chemical stability and reusability of the catalytic system, a continuous-flow protocol was also investigated and defined to minimize the generation of waste and optimize the continuous reuse of the catalyst. Benefits of flow conditions were proven by turnover numbers that increased from 47.5 to 1902 and also by the minimization of both leaching (9.5 vs. 1 ppm) and E-factor values (8 vs. 23 in batch).
- Ferlin, Francesco,Giannoni, Tommaso,Zuliani, Alessio,Piermatti, Oriana,Luque, Rafael,Vaccaro, Luigi
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p. 3178 - 3184
(2019/02/19)
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- Cobalt nanoparticles anchoring on nitrogen doped carbon with excellent performances for transfer hydrogenation of nitrocompounds to primary amines and N-substituted formamides with formic acid
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Cobalt nanoparticles anchoring on nitrogen doped carbon derived from pyrolysis of a cobalt complex and chitosan were developed for reduction of nitrocompounds with neat formic acid to their corresponding amines or N-substituted formamides by switch of solvents. Characterization results revealed that most of the nitrogen atoms are present as graphitic N and pyridinic N as anchoring sites, and the cobalt nanoparticles are wrapped by nitrogen doped carbon layers, endowing the catalyst with excellent activity and superior reusability.
- Zhang, Yuecheng,Cao, Pengwei,Zhang, Hong-Yu,Yin, Guohui,Zhao, Jiquan
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- The immobilized Ni(II)-thiourea complex on silica-layered copper ferrite: A novel and reusable nanocatalyst for one-pot reductive-acetylation of nitroarenes
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In this study, magnetically nanoparticles of CuFe2O4@SiO2@PTMS@Tu@Ni(II) as novel and reusable catalyst were prepared. Synthesis of the Ni (II)-nanocatalyst was carried out through the complexation of Ni(OAc)2·4H2O with the immobilized thiourea on silica-layered CuFe2O4. The prepared nanocomposite system was then characterized using SEM, EDX, XRD, VSM, ICP-OES, Raman, UV–Vis and FT-IR analyses. Catalytic activity of the Ni(II)-CuFe2O4 system was investigated towards rapid reduction of aromatic nitro compounds to arylamines with sodium borohydride as well as one-pot reductive-acetylation of nitroarenes to acetanilides with NaBH4/Ac2O system without the isolation of intermediate arylamines. All reactions were carried out in H2O within 3–7?min to afford the products arylamines/acetanilides in high to excellent yields. Reusability of the Ni(II)-nanocatalyst was examined for seven consecutive cycles without the significant loss of the catalytic activity.
- Zeynizadeh, Behzad,Shokri, Zahra,Hasanpour Galehban, Morteza
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- One-Pot Synthesis of Heterobimetallic Metal–Organic Frameworks (MOFs) for Multifunctional Catalysis
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A one-pot synthesis of bimetallic metal–organic frameworks (Co/Fe-MOFs) was achieved by treating stoichiometric amounts of Fe and Co salts with 2-aminoterephthalic acid (NH2-BDC). Monometallic Fe (catalyst A) and Co (catalyst F) were also prepared along with mixed-metal Fe/Co catalysts (B–E) by changing the Fe/Co ratio. For mixed-metal catalysts (B–E) SEM energy-dispersive X-ray (EDX) analysis confirmed the incorporation of both Fe and Co in the catalysts. However, a spindle-shaped morphology, typically known for the Fe-MIL-88B structure and confirmed by PXRD analysis, was only observed for catalysts A–D. To test the catalytic potential of mixed-metal MOFs, reduction of nitroarenes was selected as a benchmark reaction. Incorporation of Co enhanced the activity of the catalysts compared with the parent NH2-BDC-Fe catalyst. These MOFs were also tested as electrocatalysts for the oxygen evolution reaction (OER) and the best activity was exhibited by mixed-metal Fe/Co-MOF (Fe/Co batch ratio=1). The catalyst provided a current density of 10 mA cm?2 at 410 mV overpotential, which is comparable to the benchmark OER catalyst (i.e., RuO2). Moreover, it showed long-term stability in 1 m KOH. In a third catalytic test, dehydrogenation of sodium borohydride showed high activity (turnover frequency=87 min?1) and hydrogen generation rate (67 L min?1 g?1 catalyst). This is the first example of the synthesis of bimetallic MOFs as multifunctional catalysts particularly for catalytic reduction of nitroarenes and dehydrogenation reactions.
- Iqbal, Bushra,Saleem, Murtaza,Arshad, Salman Noshear,Rashid, Jamshaid,Hussain, Naveed,Zaheer, Muhammad
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p. 10490 - 10498
(2019/07/15)
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- Catalytic hydrogenation of carbonyl and nitro compounds using an [: N, O] -chelate half-sandwich ruthenium catalyst
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A series of N,O-chelate half-sandwich ruthenium complexes for both carbonyl and nitro compound hydrogenation have been synthesized based on β-ketoamino ligands. All complexes exhibited high activity for the catalytic hydrogenation of a series of ketones and nitroarenes with molecular H2 as the reducing reagent in aqueous medium. Consequently, the catalytic system showed the catalytic TON values of 950 for 1-phenylethanol in acetophenone hydrogenation and 1960 for 1-chloro-4-nitrobenzene in p-chloroaniline hydrogenation. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. The neutral ruthenium complexes 1-4 were fully characterized using NMR, IR, and elemental analysis. Molecular structures of complexes 2 and 4 were further confirmed using single-crystal X-ray diffraction analysis.
- Yao, Zi-Jian,Zhu, Jing-Wei,Lin, Nan,Qiao, Xin-Chao,Deng, Wei
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p. 7158 - 7166
(2019/06/13)
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- Green and convenient protocols for the efficient reduction of nitriles and nitro compounds to corresponding amines with NaBH4 in water catalyzed by magnetically retrievable CuFe2O4 nanoparticles
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Abstract: In this study, firstly, CuFe2O4 nanoparticles were prepared by a simple operation. The structure of the mentioned nanoparticles was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, vibrating sample magnetometer and also Brunauer–Emmett–Teller and Barrett–Joyner–Halenda analyses. The prepared magnetically copper ferrite nanocomposite was successfully applied as a simple, cost-effective, practicable, and recoverable catalyst on the green, highly efficient, fast, base-free, and ligand-free reduction of nitriles and also on the affordable and eco-friendly reduction of nitro compounds with the broad substrate scope to the corresponding amines with NaBH4 in water at reflux in high to excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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- COMPOUNDS FOR THIOL-TRIGGERED COS AND/OR H2S RELEASE AND METHODS OF MAKING AND USING THE SAME
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Disclosed herein are embodiments of a compound that is capable of releasing COS and/or H2S upon reaction with a thiol-containing compound. The compound embodiments also can produce a detectable signal (e.g., a fluorescent signal) substantially concomitantly with COS and/or H2S release and/or can release an active agent, such as a therapeutic agent. Methods of making and using the compound embodiments also are disclosed.
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Page/Page column 35
(2019/12/25)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 3800 - 3806
(2019/07/12)
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- Amino-Modified Silica-Supported Copper-Palladium Alloy. Synthesis and Use in Selective Hydrogenation of Disubstituted Nitroarenes in a Flow Micro Reactor
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A copper-palladium catalyst supported on amino-modified silica has been synthesized by chemical reduction. It has been found that submicron particles of a copper-palladium alloy are formed on the silica surface. Unlike commercially available palladium catalysts (Pd/Al2O3, Pd/C, Pd/BaSO4), the synthesized copper-palladium catalyst makes it possible to selectively reduce the nitro group in 3-nitrobenzaldehyde and 1-chloro-4-nitrobenzene.
- Nurmukhametova,Belov,Sultanova,Vorob’ev,Osin, Yu. N.,Burilov,Antipin
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- From alkylarenes to anilines via site-directed carbon–carbon amination
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Anilines are fundamental motifs in various chemical contexts, and are widely used in the industrial production of fine chemicals, polymers, agrochemicals and pharmaceuticals. A recent development for the synthesis of anilines uses the primary amination of C–H bonds in electron-rich arenes. However, there are limitations to this strategy: the amination of electron-deficient arenes remains a challenging task and the amination of electron-rich arenes has a limited control over regioselectivity—the formation of meta-aminated products is especially difficult. Here we report a site-directed C–C bond primary amination of simple and readily available alkylarenes or benzyl alcohols for the direct and efficient preparation of anilines. This chemistry involves a novel C–C bond transformation and offers a versatile protocol for the synthesis of substituted anilines. The use of O2 as an environmentally benign oxidant is demonstrated, and studies on model compounds suggest that this method may also be used for the depolymerization of lignin.
- Liu, Jianzhong,Qiu, Xu,Huang, Xiaoqiang,Luo, Xiao,Zhang, Cheng,Wei, Jialiang,Pan, Jun,Liang, Yujie,Zhu, Yuchao,Qin, Qixue,Song, Song,Jiao, Ning
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- Aromatic amine compound synthesis method
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The invention discloses an aromatic amine compound synthesis method which is characterized in that the method is implemented according to any of two methods. The first method includes the steps: mixing an alkyl aromatic compound with a general formula (I) and a nitrogen-containing compound with a general formula (II); performing reaction on mixture under an oxidizing agent and an organic solvent to obtain an aromatic amine compound with a general formula (III). The second method includes the steps: mixing an aromatic alcohol derivative with a general formula (I') and the nitrogen-containing compound with the general formula (II); performing reaction on mixture under an acid additive and an organic solvent to prepare the aromatic amine compound with the general formula (III). According to the method, a lot of alkyl aromatic compounds or aromatic alcohol derivatives firstly serve as raw materials, and the raw materials are reacted to generate the aromatic amine compound without the action of metal catalysis. Compared with a traditional synthesis method, the synthesis method has the advantages that the method is high in yield and simple in condition, waste discharging amount is less,metal participation is omitted, a reaction device is simple, industrial production is easily achieved and the like. The method has a wide application prospect.
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Paragraph 0165-0167
(2019/01/23)
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- Selective Synthesis of Primary Anilines from NH3 and Cyclohexanones by Utilizing Preferential Adsorption of Styrene on the Pd Nanoparticle Surface
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Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH3 and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N-cyclohexylidene-anilines), followed by hydrogenation to produce N-cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca10(PO4)6(OH)2) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N-cyclohexylidene-anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH3 and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.
- Koizumi, Yu,Jin, Xiongjie,Yatabe, Takafumi,Miyazaki, Ray,Hasegawa, Jun-ya,Nozaki, Kyoko,Mizuno, Noritaka,Yamaguchi, Kazuya
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supporting information
p. 10893 - 10897
(2019/07/12)
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