- Method for preparing amine through catalytic reduction of nitro compound by cyclic (alkyl) (amino) carbene chromium complex
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The cyclic (alkyl) (amino) carbene chromium complex is prepared from corresponding ligand salt, alkali and CrCl3 and used for catalyzing pinacol borane to reduce nitro compounds in an ether solvent under mild conditions to generate corresponding amine. The method for preparing amine has the advantages of cheap and accessible raw materials, mild reaction conditions, wide substrate application range, high selectivity and the like, and is simple to operate.
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Paragraph 0015
(2021/04/17)
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- COPPER NANOPARTICLE BASED CHEMOSELECTIVE REDUCTION
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The instant invention provides processes for a chemo selective reduction of a nitro group within a compound in the presence of other groups which can also be reduced. This aspect of the present invention provides an ammonia borane (AB) initiated chemoselective reduction process of a nitro group contained within a compound in the presence of a copper (Cu) nanoparticle based catalyst. The invention is also directed to Copper (Cu) nanoparticle (NP) based catalysts, selected from Cu/WOx, Cu/SiO2, and Cu/C; wherein x represents an integer having a value of from about 2 to about 3.5, used in the chemo selective reduction of a nitro group contained within a compound in the presence of other groups which can also be reduced.
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Paragraph 0050; 0051
(2021/11/20)
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- Effect of the Linking Group on the Thermoelectric Properties of Poly(Schiff Base)s and Their Metallopolymers
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As polymer-based thermoelectric (TE) materials possess attractive features such as light weight, flexibility, low toxicity and ease of processibility, an increasing number of conducting polymers and their composites with high TE performances have been developed in recent years. Up to date, however, the research focusing on the structure-performance relationship remains rare. In this paper, two series of poly(Schiff base)s with either C=C or C≡C linker and their metallopolymers were synthesized and doped with single-walled carbon nanotubes to evaluate how the linking groups affected the TE properties of the resulting composites. Apart from the effect exerted by the morphology, experimental results suggested that the linkers played a key role in determining the band gaps, preferred molecular conformation and extent of conjugation of the polymers, which became key factors that influenced the TE properties of the resulting materials. Additionally, upon coordination with transition metal ions, the TE properties could be tuned readily.
- Li, Jiahua,Wang, Zitong,Sun, Zelin,Xu, Linli,Wong, Wai-Yeung
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supporting information
p. 1911 - 1917
(2021/06/21)
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- NiFe2O4@SiO2@ZrO2/SO42-/Cu/Co nanoparticles: A novel, efficient, magnetically recyclable and bimetallic catalyst for Pd-free Suzuki, Heck and C-N cross-coupling reactions in aqueous media
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The novel heterogeneous bimetallic nanoparticles of Cu-Co were synthesized based on magnetic nanoparticles, and the magnetic nanocatalyst was characterized by XRD, FE-SEM, EDX mapping, BET, TEM, HRTEM, FTIR, TGA, and VSM. This catalyst was successfully applied as a recyclable magnetically catalyst in Heck, Suzuki, and C-N cross-coupling reactions with various aryl halides (iodides, bromides, and chlorides as challengeable substrates), with olefins, phenylboronic acid, and amines, respectively. We considered the rise of synergetic effects from the different Lewis acid and Br?nsted acid sites present in the catalyst. The catalyst was synthesized with cheap, available materials and a simple synthesis method. The catalyst can be separated easily using an external magnet. It was recycled for more than ten runs without a sensible loss of its catalytic activity, and no significant leaching of the Cu and Co quantity was observed. The significant benefits of the method are high-level generality, simple operation, and there are no heavy metals and toxic solvents. This is a quick, easy, efficacious and environmentally friendly protocol, and no by-products are formed in the reaction. These features make it an appropriate practical alternative protocol. In comparison with recent works, the other advantage of this catalyst is the synthesis of a wide variety of C-C and C-N bond derivatives (more than 40 derivatives). The other significant advantage is the low temperature of the reaction and the use of the least possible amount of the catalyst (0.003 g). The efficiency was good to excellent and the catalyst selectivity has been high. We aspire that our study inspires more interest to design novel catalysts based on using low-cost metal ions (such as cobalt and copper) in the cross-coupling reactions. This journal is
- Alavi G., Seyyedeh Ameneh,Nasseri, Mohammad Ali,Kazemnejadi, Milad,Allahresani, Ali,Hussainzadeh, Mahdi
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p. 7741 - 7757
(2021/05/13)
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- A new Pd(II)-supported catalyst on magnetic SBA-15 for C-C bond formation via the Heck and Hiyama cross-coupling reactions
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Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nanoparticles between SBA-15 channels. It was silylated with N-(3-(trimethoxysilyl)propyl)picolinamide (TMS-PCA) and then complexed with Pd(II). The obtained supported Pd(II) catalyst (MNP@SiO2-SBA-PCA) was characterized by conventional methods. The prepared magnetic catalyst showed high activity in the Heck and Hiyama reactions under optimal reaction conditions, including solvent, amount of catalyst, base, and temperature. Aryl bromides and iodides showed better results than aryl chlorides, and the catalyst exhibited noticeable stability and reused several times.
- Rahimi, Leila,Mansoori, Yagoub,Nuri, Ayat,Koohi-Zargar, Behzad,Esquivel, Dolores
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- A New Nitrogen Pd(II) Complex Immobilized on Magnetic Mesoporous Silica: A Retrievable Catalyst for C–C Bond Formation
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Abstract: A new nitrogen ligand, i.e. 1,3-di-(o-aminophenoxy)-2-propyl propargyl ether (DPPE), has been synthesized and characterized. Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nano-particles (MNPs) between SBA-15 channels. DPPE palladium dichloride (MNP@SiO2-SBA-DPPE-Pd(II)) was then prepared via click chemistry and fully characterized. The activity and recyclability of supported magnetic Pd(II) catalyst were evaluated in Heck coupling reaction after optimizing the optimal reaction conditions including solvent, amount of catalyst, base and temperature. Aryl iodides and aryl bromides showed enhanced activity compared to those of aryl chlorides in the Heck reaction. The catalyst was easily separated magnetically, reused in five runs sequentially, and no significant loss of activity was observed. Graphic Abstract: [Figure not available: see fulltext.]
- Mousavi, Samira,Mansoori, Yagoub,Nuri, Ayat,Koohi-Zargar, Behzad
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p. 1923 - 1936
(2020/11/30)
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- Copper(0) nanoparticle catalyzed Z-Selective Transfer Semihydrogenation of Internal Alkynes
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The use of copper(0) nanoparticles in the transfer semihydrogenation of alkynes has been investigated as a lead-free alternative to Lindlar catalysts. A stereo-selective methodology for the hydrogenation of internal alkynes to the corresponding (Z)-alkenes in high isolated yields (86% average) has been developed. This green and sustainable transfer hydrogenation protocol relies on non-noble copper nanoparticles for reduction of both electron-rich and electron-deficient, aliphatic-substituted and aromatic- substituted internal alkynes. Polyols, such as ethylene glycol and glycerol, have been proven to act as hydrogen sources, and excellent stereo- and chemoselectivity have been observed. Enabling technologies, such as microwave and ultrasound irradiation are shown to enhance heat and mass transfer, whether used alone or in combination, resulting in a decrease in reaction time from hours to minutes. (Figure presented.).
- Moran, Maria Jesus,Martina, Katia,Bieliunas, Vidmantas,Baricco, Francesca,Tagliapietra, Silvia,Berlier, Gloria,De Borggraeve, Wim M.,Cravotto, Giancarlo
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supporting information
p. 2850 - 2860
(2021/05/06)
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- A simple and efficientin situgenerated copper nanocatalyst for stereoselective semihydrogenation of alkynes
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Development of a simple, effective, and practical method for (Z)-selective semihydrogenation of alkynes has been considered necessary for easy-to-access applications at organic laboratory scales. Herein, (Z)-selective semihydrogenation of alkynes was achieved using a copper nanocatalyst which was generatedin situsimply by adding ammonia borane to an ethanol solution of copper sulfate. Different types of alkynes including aryl-aryl, aryl-alkyl, and aliphatic alkynes were selectively reduced to (Z)-alkenes affording up to 99% isolated yield. The semihydrogenation of terminal alkynes to alkenes and gram-scale applications were also reported. In addition to eliminating catalyst preparation, the proposed approach is simple and practical and serves as a suitable alternative method to the conventional Lindlar catalyst.
- Park, Byoung Yong,Lim, Taeho,Han, Min Su
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supporting information
p. 6891 - 6894
(2021/07/19)
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- Dinuclear cobalt complex-catalyzed stereodivergent semireduction of alkynes: Switchable selectivities controlled by H2O
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Catalytic semireduction of internal alkynes to alkenes is very important for organic synthesis. Although great success has been achieved in this area, switchable Z/E stereoselectivity based on a single catalyst for the semireduction of internal alkynes is a longstanding challenge due to the multichemo- and stereoselectivity, especially based on less-expensive earth-abundant metals. Herein, we describe a switchable semireduction of alkynes to (Z)- or (E)-alkenes catalyzed by a dinuclear cobalt complex supported by a macrocyclic bis pyridyl diimine (PDI) ligand. It was found that cis-reduction of the alkyne occurs first and the Z-E alkene stereoisomerization process is formally controlled by the amount of H2O, since the concentration of H2O may influence the catalytic activity of the catalyst for isomerization. Therefore, this protocol provides a facile way to switch to either the (Z)- or (E)-olefin isomer in a single transformation by adjusting the amount of water.
- Chen, Ke,Zhu, Hongdan,Li, Yuling,Peng, Qian,Guo, Yinlong,Wang, Xiaoming
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p. 13696 - 13705
(2021/11/16)
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- Ruthenium-Catalyzed E-Selective Alkyne Semihydrogenation with Alcohols as Hydrogen Donors
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Selective direct ruthenium-catalyzed semihydrogenation of diaryl alkynes to the corresponding E-alkenes has been achieved using alcohols as the hydrogen source. The method employs a simple ruthenium catalyst, does not require external ligands, and affords the desired products in > 99% NMR yield in most cases (up to 93% isolated yield). Best results were obtained using benzyl alcohol as the hydrogen donor, although biorenewable alcohols such as furfuryl alcohol could also be applied. In addition, tandem semihydrogenation-alkylation reactions were demonstrated, with potential applications in the synthesis of resveratrol derivatives.
- Ekebergh, Andreas,Begon, Romain,Kann, Nina
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p. 2966 - 2975
(2020/03/04)
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- Photocatalyst-free visible light promoted: E → Z isomerization of alkenes
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A simple and green method of visible light driven photocatalytic E to Z isomerization of alkenes has been developed. A variety of (Z)-alkenes can be prepared in the presence of visible light, without any additional photocatalyst. This protocol features photocatalyst-free conditions, which are mild, tolerant, and operationally simple, and is easy to implement.
- Xu, Jianbin,Liu, Na,Lv, Haiping,He, Chixian,Liu, Zining,Shen, Xianfu,Cheng, Feixiang,Fan, Baomin
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supporting information
p. 2739 - 2743
(2020/06/17)
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- Superior activity and selectivity of heterogenized cobalt catalysts for hydrogenation of nitroarenes
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The development of improved catalysts for highly selective hydrogenation of nitroarenes is described. For this purpose Co nanoparticles were supported on ordered mesoporous carbon CMK-3 and characterized in detail. The optimal CMK-3-CoPc catalyst exhibits excellent hydrogenation activity for several (hetero)aromatic nitro compounds and yielded the corresponding anilines under mild conditions (40 °C, 20 bar H2).
- Li, Wu,Artz, Jens,Broicher, Cornelia,Junge, Kathrin,Hartmann, Heinrich,Besmehn, Astrid,Palkovits, Regina,Beller, Matthias
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p. 157 - 162
(2019/01/10)
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- Synergistic Effects of ppm Levels of Palladium on Natural Clinochlore for Reduction of Nitroarenes
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Augmenting the modified naturally occurring clay clinochlore with ppm amounts of palladium leads to a new and very effective reagent for the reduction of numerous aromatic nitro species. When palladium nanoparticles are supported on pyridyltriazole-modified clinochlore, iron within clinochlore acts synergistically with palladium to catalyze the reduction of a wide variety of nitroarenes at room temperature in aqueous media. Based on E-factor calculations, the catalyst system is found to be in line with green chemistry standards and can be recycled up to five times.
- Gholinejad, Mohammad,Oftadeh, Erfan,Shojafar, Mohammad,Sansano, José M.,Lipshutz, Bruce H.
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p. 4240 - 4248
(2019/09/06)
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- Mesoporous Hierarchically Hollow Flower-Like CoAl-LDH@N,S-doped Graphene@Pd Nanoarchitectures for Heck Couplings
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Abstract: A smart strategy for the synthesis of hierarchical CoAl-LDH hollow spheres assembled with nitrogen and sulfur co-doped graphene for high holding of palladium nanoparticles (CoAl-LDH@N,S-G@Pd) is reported. This architecture exhibited excellent activity in Heck reactions with TOF as high as 1633?h?1 due to a strong metal–support interaction, good electron transfers and high surface area. Graphic Abstract: [Figure not available: see fulltext.].
- Rohani, Sahar,Mohammadi Ziarani, Ghodsi,Badiei, Alireza,Ziarati, Abolfazl,Luque, Rafael
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p. 2984 - 2993
(2019/07/05)
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- Bis(bipyridine) ruthenium(ii) bis(phosphido) metalloligand: Synthesis of heterometallic complexes and application to catalytic (E)-selective alkyne semi-hydrogenation
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The first phosphido derivative of the bis(bipyridine) ruthenium(ii) fragment, cis-[(bpy)2Ru(PPh2)2] ([RuP2]), has been developed and applied as a P-donor metalloligand to form new Ru-Rh, Ru-Ir and Ru2Cu2 heterometallic complexes. The Ru-Ir hydride complex [([RuP2])IrH(NCMe)3][BF4]2 exhibits significant catalytic activity for (E)-selective semi-hydrogenation of alkynes.
- Takemoto, Shin,Kitamura, Manami,Saruwatari, Shuhei,Isono, Atsutaka,Takada, Yoko,Nishimori, Rie,Tsujiwaki, Mina,Sakaue, Naoki,Matsuzaka, Hiroyuki
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supporting information
p. 1161 - 1165
(2019/01/28)
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- Diboron-Assisted Copper-Catalyzed Z-Selective Semihydrogenation of Alkynes Using Ethanol as a Hydrogen Donor
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We herein describe a B2Pin2-assisted copper-catalyzed semihydrogenation of alkynes. A variety of alkenes were obtained in good to excellent yields with Z-selectivity under mild reaction conditions. Mechanistic studies indicated that a transfer hydrogenation process was involved and ethanol acted as both a solvent and a hydrogen donor in this reaction. The present protocol enabled convenient synthesis of deuterium-substituted Z-alkenes such as Z-Combretastain A4-d2 in a high deuteration ratio by using readily available ethanol-d1 as the deuterium source.
- Bao, Hanyang,Zhou, Bingwei,Jin, Hongwei,Liu, Yunkui
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p. 3579 - 3589
(2019/03/11)
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- Cobalt catalyzed stereodivergent semi-hydrogenation of alkynes using H2O as the hydrogen source
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Cobalt-catalyzed stereodivergent semi-hydrogenation of internal alkynes to alkenes is developed. The reaction proceeded through transfer hydrogenation under mild conditions using a base metal CoI2 as the catalyst, and H2O/MeOH as the hydrogen source with Zn as the reductant. The E/Z-selectivity of the product could be switched by changing the solvent and by inclusion/exclusion of a bidentate phosphine ligand (dppe). This method provides a simple and cost effective pathway for the synthesis of 1,2-dideuterioalkenes.
- Li, Kangkui,Khan, Ruhima,Zhang, Xuexin,Gao, Yang,Zhou, Yongyun,Tan, Heng,Chen, Jingchao,Fan, Baomin
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supporting information
p. 5663 - 5666
(2019/05/21)
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- Monodisperse nickel-nanoparticles for stereo- and chemoselective hydrogenation of alkynes to alkenes
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Here, we report the use of monosaccharides for the preparation of novel nickel nanoparticles (NP), which constitute selective hydrogenation catalysts. For example, immobilization of fructose and Ni(OAc)2 on silica and subsequent pyrolysis under inert atmosphere produced graphitic shells encapsulated Ni-NP with uniform size and distribution. Interestingly, fructose acts as structure controlling compound to generate specific graphitic layers and the formation of monodisperse NP. The resulting stable and reusable catalysts allow for stereo- and chemoselective semihydrogenation of functionalized and structurally diverse alkynes in high yields and selectivity.
- Murugesan, Kathiravan,Alshammari, Ahmad S.,Sohail, Manzar,Beller, Matthias,Jagadeesh, Rajenahally V.
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p. 372 - 377
(2019/01/26)
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- Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts
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The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Alshammari, Ahmad S.,Pohl, Marga-Martina,Beller, Matthias,Jagadeesh, Rajenahally V.
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p. 8553 - 8560
(2018/11/30)
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- Chemoselective hydrogenation of unsaturated nitro compounds to unsaturated amines by Ni-Sn alloy catalysts
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Ni-Sn alloy catalysts were prepared and applied to the hydrogenation of 4-nitrostyrene at 383423 K using H2 gas as the hydrogen donor. Ni3Sn2 alloy showed a significantly high conversion and selectivity towards 4-aminostyrene (Conv. 100%, Sel. 99%). Various unsaturated nitro compounds were also successfully converted into their corresponding unsaturated amines.
- Yamanaka, Nobutaka,Hara, Takayoshi,Ichikuni, Nobuyuki,Shimazu, Shogo
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p. 971 - 974
(2018/08/24)
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- Room-Temperature Chemoselective Reduction of 3-Nitrostyrene to 3-Vinylaniline by Ammonia Borane over Cu Nanoparticles
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We report a new strategy of controlling catalytic activity and selectivity of Cu nanoparticles (NPs) for the ammonia borane initiated hydrogenation reaction. Cu NPs are active and selective for chemoselective reduction of nitrostyrene to vinylaniline under ambient conditions. Their activity, selectivity, and more importantly, stability are greatly enhanced by their anchoring on WO2.72 nanorods, providing a room-temperature full conversion of nitrostyrene selectively to vinylaniline (>99% yield). Compared with all other catalysts developed thus far, our new Cu/WO2.72 catalyst shows much enhanced hydrogenation selectivity and stability without the use of pressured hydrogen. The synthetic approach demonstrated here can be extended to prepare various M/WO2.72 catalysts (M = Fe, Co, Ni), with M being stabilized for many chemical reactions.
- Shen, Mengqi,Liu, Hu,Yu, Chao,Yin, Zhouyang,Muzzio, Michelle,Li, Junrui,Xi, Zheng,Yu, Yongsheng,Sun, Shouheng
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supporting information
p. 16460 - 16463
(2018/12/11)
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- Chemoselective Hydrogenation of Nitroarenes Catalyzed by Molybdenum Sulphide Clusters
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Herein, we describe an atom efficient and general protocol for the chemoselective hydrogenation of nitroarenes to anilines catalyzed by well-defined diimino and diamino cubane-type Mo3S4 clusters. The novel diimino [Mo3S4Cl3(dnbpy)3]+ ([5]+) (dnbpy=4,4′-dinonyl-2,2′-dipyridyl, L1) trinuclear complex was synthesized in high yields by simple ligand substitution reactions starting from the thiourea (tu) [Mo3S4(tu)8(H2O)]Cl4?4 H2O (3) precursor. This strategy has also been successfully adapted for the isolation of the diamino [Mo3S4Cl3(dmen)3](BF4) ([6](BF4)), (dmen=N,N′-dimethylethylenediamine) salt. Applying these catalysts, high selectivity in the hydrogenation of functionalized nitroarenes has been accomplished. Over thirty anilines bearing synthetically functional groups have been synthesized in 70 to 99 % yield. Notably, the integrity of the cluster core is preserved during catalysis. Based on kinetic studies on the hydrogenation of nitrobenzene and other potential reaction intermediates, the direct reduction to aniline is the preferential route.
- Pedrajas, Elena,Sorribes, Iván,Gushchin, Artem L.,Laricheva, Yuliya A.,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
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p. 1128 - 1134
(2017/03/27)
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- Co-based heterogeneous catalysts from well-defined Α-diimine complexes: Discussing the role of nitrogen
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Ar-BIANs and related α-diimine Co complexes were wet impregnated onto Vulcan XC 72 R carbon black powder and used as precursors for the synthesis of heterogeneous supported nanoscale catalysts by pyrolysis under argon at 800?°C. The catalytic materials feature a core-shell structure composed of metallic Co and Co oxides decorated with nitrogen-doped graphitic layers (NGr). These catalysts display high activity in the liquid phase hydrogenation of aromatic nitro compounds (110?°C, 50 bar H2) to give chemoselectively substituted aryl amines. The catalytic activity is closely related to the amount and type of nitrogen atoms in the final catalytic material, which suggests a heterolytic activation of dihydrogen.
- Formenti, Dario,Ferretti, Francesco,Topf, Christoph,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Junge, Kathrin,Beller, Matthias,Ragaini, Fabio
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- Orthopalladated complexes of phosphorus ylide: Poly(N-vinyl-2-pyrrolidone)-stabilized palladium nanoparticles as reusable heterogeneous catalyst for Suzuki and Heck cross-coupling reactions
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The phosphorus ylide [Ph3PCHC(O)C6H4-NO2–4] reacted with Pd(OAc)2 to give the C,C-orthometallated complex [Pd{κ2(C,C)-C6H4PPh2C(H)CO(C6H4-NO2–4)}(μ-OAc)]2, which underwent bridge exchange reaction with NaN3, NaCl, KBr and KI, respectively, to afford the binuclear C,C-orthopalladated complexes [Pd{κ2(C,C)-C6H4PPh2C(H)CO(C6H4-NO2–4)}(μ-X)]2 (X?=?N3 (1), Cl (2), Br (3) and I (4)). The complexes were identified using spectroscopy (infrared and NMR), CHNS technique and single-crystal X-ray structure analysis. Thereafter, palladium nanoparticles with narrow size distribution were easily prepared using the refluxing reaction of iodo-bridged orthopalladated complex 4 with poly(N-vinyl-2-pyrrolidone) (PVP) as the protecting group. The PVP-stabilized palladium nanoparticles were characterized using a variety of techniques including X-ray diffraction, transmission and scanning electron microscopies, energy-dispersive X-ray spectroscopy, inductively coupled plasma analysis and Fourier transform infrared spectroscopy. The catalytic activity of the PVP-stabilized palladium nanoparticles was evaluated in the Suzuki reaction of phenylboronic acid and the Heck reaction of styrene with aryl halides of varying electron densities. This catalyst exhibited excellent catalytic activity for Suzuki cross-coupling reactions in ethanol–water. Notably, aryl chlorides which are cheaper and more accessible than their bromide and iodide counterparts also reacted satisfactorily using this catalyst. After completion of reactions, the catalyst could be separated using a simple method and used many times in repeat cycles without considerable loss in its activity.
- Karami, Kazem,Abedanzadeh, Sedigheh,Vahidnia, Omolbanin,Herves, Pablo,Lipkowski, Janusz,Lyczko, Krzysztof
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- Selective hydrogenation method, catalyst used for the method
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PROBLEM TO BE SOLVED: To provide a selective hydrogenation method for selectively hydrogenating, into amino groups with high efficiency, nitro groups of an aromatic compound including carbon-carbon double bonds and nitro groups and a selective hydrogenation method for selectively hydrogenating, into hydroxyl groups, aldehyde groups of a terpenoid including carbon-carbon double bonds and aldehyde groups.SOLUTION: The provided selective hydrogenation method of an aromatic compound including carbon-carbon double bonds and nitro groups or a terpenoid including carbon-carbon double bonds and aldehyde groups features the contact, with a hydrogen gas in the presence of a silver-cerium oxide composite comprising silver component particles and cerium oxide supported on surfaces of the silver component particles within a liquid phase including an organic solvent, of an aromatic compound including carbon-carbon double bonds and nitro groups or a terpenoid including carbon-carbon double bonds and aldehyde groups so as to induce a selective hydrogenation and conversion, into amino groups or hydroxyl groups, of the nitro groups included within the aromatic compound or aldehyde groups included within the terpenoid.
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Paragraph 0080-0081
(2017/05/02)
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- Synthesis of Nickel Nanoparticles with N-Doped Graphene Shells for Catalytic Reduction Reactions
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The synthesis of novel nanoparticles is of general importance for the development of efficient heterogeneous catalysts. Herein, the preparation of carbon-supported nickel-based nanoparticles (NPs), modified by nitrogen-doped graphene layers, is reported for the first time. The resulting materials were characterized in detail by TEM, X-ray photoelectron spectroscopy (XPS), XRD, elemental analysis (EA), electron paramagnetic resonance (EPR), temperature-programmed reduction (TPR), BET, and Raman analysis. Initial catalytic tests revealed the potential of this class of compounds in hydrogenation reactions.
- Pisiewicz, Sabine,Formenti, Dario,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Junge, Kathrin,Topf, Christoph,Bachmann, Stephan,Scalone, Michelangelo,Beller, Matthias
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p. 129 - 134
(2016/01/25)
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- Fe2O3/NGr@C- and Co-Co3O4/NGr@C-catalysed hydrogenation of nitroarenes under mild conditions
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An improved hydrogenation of nitroarenes using nano-structured iron- and cobalt-based catalysts is presented. Modifications of the heterogeneous catalysts by N-doped graphene-flakes are crucial for the success of selective reductions. The use of polar solvents and basic additives has a significant positive influence on the rate of reduction of nitroarenes. This allows performing non-noble metal-catalysed hydrogenations under very mild reaction conditions (e.g. 70 °C and 20 bar). On the basis of the obtained catalytic results a heterolytic mechanism for the hydrogenation process is postulated, too.
- Formenti, Dario,Topf, Christoph,Junge, Kathrin,Ragaini, Fabio,Beller, Matthias
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p. 4473 - 4477
(2016/07/06)
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- Well-structured bimetallic surface capable of molecular recognition for chemoselective nitroarene hydrogenation
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Unprecedented molecular recognition ability governed by a simple bimetallic surface is reported. A series of Rh-based ordered alloys supported on silica gel (RhxMy/SiO2, where M is Bi, Fe, Ga, Ge, In, Ni, Pb, Sb, Sn, or Zn) were tested in the hydrogenation of nitrostyrene to form aminostyrene. RhIn/SiO2 showed remarkably high catalytic activity and good selectivity under 1 atm H2 at room temperature. Moreover, various other nitroarenes containing carbonyl, cyano, or halo moieties were selectively hydrogenated into the corresponding amino derivatives using RhIn/SiO2. Kinetic study and density functional theory (DFT) calculations revealed that the high selectivity originates from RhIn/SiO2 adsorbing nitro groups much more favorably than vinyl groups. In addition, the DFT calculations indicated that the RhIn ordered alloy presents concave Rh rows and convex In rows on its surface, which are able to capture the nitro group with end-on geometry while effectively minimizing vinyl-π adsorption. Thus, the specific and highly ordered surface structure of RhIn enables the chemoselective molecular recognition of nitro groups over vinyl groups through geometric and chemical effects.
- Furukawa, Shinya,Takahashi, Katsuya,Komatsu, Takayuki
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p. 4476 - 4484
(2016/07/06)
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- Ligand-Controlled Cobalt-Catalyzed Transfer Hydrogenation of Alkynes: Stereodivergent Synthesis of Z- and E-Alkenes
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Herein, we report a novel cobalt-catalyzed stereodivergent transfer hydrogenation of alkynes to Z- and E-alkenes. Effective selectivity control is achieved based on a rational catalyst design. Moreover, this mild system allows for the transfer hydrogenation of alkynes bearing a wide range of functional groups in good yields using catalyst loadings as low as 0.2 mol %. The general applicability of this procedure is highlighted by the synthesis of more than 50 alkenes with good chemo- and stereoselectivity. A preliminary mechanistic study revealed that E-alkene product was generated via sequential alkyne hydrogenation to give Z-alkene intermediate, followed by a Z to E alkene isomerization process.
- Fu, Shaomin,Chen, Nan-Yu,Liu, Xufang,Shao, Zhihui,Luo, Shu-Ping,Liu, Qiang
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supporting information
p. 8588 - 8594
(2016/07/27)
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- Dual optimization approach to bimetallic nanoparticle catalysis: Impact of M1/M2 ratio and supporting polymer structure on reactivity
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A dual optimization approach to nanoparticle catalysis is reported in which both the composition of a bimetallic nanoparticle and the electronic properties of the supporting polystyrene-based polymer can be varied to optimize reactivity and chemoselectivity in nitroarene reductions. Ruthenium-cobalt nanoparticles supported on polystyrene are shown to catalyze nitroarene reductions at room temperature with exceptional activity, as compared with monometallic ruthenium catalysts. Both the identity of the second metal and the M1/M2 ratio show a profound effect on the chemoselectivity of nitroarene reductions. These polymer-supported bimetallic catalysts are shown to react with nearly complete chemoselectivity for nitro group reduction over a variety of easily reducible functional groups. The electronic properties of the supporting polymer also have a significant impact on catalysis, in which electron-deficient polystyrenes enable 100% conversion to the aniline product in just 20 min at room temperature. Polymer effects are also shown to influence the mechanism of the reduction reaction, in addition to accelerating the rate, confirming the impact of the polymer structure on catalytic efficiency. These catalysts are easily prepared in a single step from commercial materials and can be readily recycled without loss of activity.
- Udumula, Venkatareddy,Tyler, Jefferson H.,Davis, Donald A.,Wang, Hao,Linford, Matthew R.,Minson, Paul S.,Michaelis, David J.
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p. 3457 - 3462
(2015/06/16)
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- Nitrogen-doped graphene-activated iron-oxide-based nanocatalysts for selective transfer hydrogenation of nitroarenes
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Nanoscaled iron oxides on carbon were modified with nitrogen-doped graphene (NGr) and found to be excellent catalysts for the chemoselective transfer hydrogenation of nitroarenes to anilines. Under standard reaction conditions, a variety of functionalized and structurally diverse anilines, which serve as key building blocks and central intermediates for fine and bulk chemicals, were synthesized in good to excellent yields.
- Jagadeesh, Rajenahally V.,Natte, Kishore,Junge, Henrik,Beller, Matthias
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p. 1526 - 1529
(2015/03/14)
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- Reduction of nitroarenes using CO and H2O in the presence of a nanostructured cobalt oxide/Nitrogen-Doped Graphene (NGr) catalyst
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The most common route to anilines is based on the reduction of the corresponding nitroarenes. In general, hydrogen is preferred as reducing agent and numerous catalytic systems are known to achieve such transformations. Besides, the use of CO/H2O as hydrogen source offers interesting possibilities for reductions. Carbon monoxide is a cheap and abundant chemical used on industrial scale for a variety of transformations. Although the reduction of nitroarenes with CO/H2O is known in the presence of noble-metal catalysts, earth-abundant inexpensive catalysts showing high selectivity have not yet been developed. In this respect, herein we present the use of a heterogeneous cobalt oxide catalyst (Co3O4/NGr@C), which is modified by nitrogen-doped graphene layers. Using this non-noble metal catalyst nitroarenes are reduced in high yields and good chemoselectivities.
- Westerhaus, Felix A.,Sorribes, Ivn,Wienh?fer, Gerrit,Junge, Kathrin,Beller, Matthias
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supporting information
p. 313 - 317
(2015/03/05)
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- Synthesis and isolation of an acyclic tridentate bis(pyridine)carbodicarbene and studies on its structural implications and reactivities
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The simple synthetic development of acyclic pincer bis(pyridine)carbodicarbene is depicted herein. Presented is the first isolated structural pincer carbodicarbene with a C-C-C angle of 143°, larger than the monodentate framework. More importantly, theore
- Hsu, Yu-Chen,Shen, Jiun-Shian,Lin, Bo-Chao,Chen, Wen-Ching,Chan, Yi-Tsu,Ching, Wei-Min,Yap, Glenn P. A.,Hsu, Chao-Ping,Ong, Tiow-Gan
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supporting information
p. 2420 - 2424
(2015/02/19)
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- Chemoselective reductions of nitroaromatics in water at room temperature
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A robust and green protocol for the reduction of functionalized nitroarenes to the corresponding primary amines has been developed. It relies on inexpensive zinc dust in water containing nanomicelles derived from the commercially available designer surfactant TPGS-750-M. This mild process takes place at room temperature and tolerates a wide range of functionalities. Highly selective reductions can also be achieved in the presence of common protecting groups.
- Kelly, Sean M.,Lipshutz, Bruce H.
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supporting information
p. 98 - 101
(2014/01/23)
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- Solid supported rhodium(0) nanoparticles: An efficient catalyst for chemo- and regio-selective transfer hydrogenation of nitroarenes to anilines under microwave irradiation
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A Solid-supported rhodium(0) (SS-Rh) catalyst has been developed and applied for the chemo- and regio-selective reduction of nitroarenes functionalized with CC multiple bonds and dinitroarenes to their corresponding amines respectively using hydrazine hydrate (N2H4· H2O) as a reducing source under mild microwave irradiation (MWI) conditions. The present methodology also shows excellent compatibility with a broad range of structurally diverse reducible functional groups. The catalyst can be recovered by simple filtration and reused for 13 cycles with consistent activity hence reduces the cost of the catalyst assertively.
- Guha, Nitul Ranjan,Bhattacherjee, Dhananjay,Das, Pralay
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supporting information
p. 2912 - 2916
(2014/05/06)
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- Chemoselective hydrogenation of nitrostyrene to aminostyrene over Pd- and Rh-based intermetallic compounds
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A noble catalytic system based on intermetallic compounds was developed for the chemoselective hydrogenation of p-nitrostyrene (NS) to p-aminostyrene (AS). The main concept of the catalyst design was to construct polar active sites consisting of two types of metals with different electronegativities. We prepared a series of Pd- and Rh-based intermetallics and investigated their catalytic properties in detail in the catalytic transfer hydrogenation of nitrobenzene and NS in the presence of 4-methyl-1-cyclohexene (MC) or methanol as a hydrogen donor. FT-IR studies of adsorbed CO confirmed that the number of Pd ensembles exposed on a surface was greatly decreased by the formation of an intermetallic phase; hence, the particle surface consisted of two metal elements being coadjacent at the atomic level. The product distribution achieved with Pd catalysts was dependent on the electronegativity of the second metal element: more electronegative metals gave higher AS selectivity and lower p-ethylnitrobenzene selectivity. Rh catalysts selectively gave AS, and their AS yields increased as the electronegativity of the second metal increased. The results revealed that an increase in the electronegativity of the second metal element provided polar sites and enhanced the activation of methanol as a hydrogen donor, which accelerated the hydrogenation of the nitro group of NS and, hence, improved the yield of AS. The high selectivity of Rh catalysts was due to the absence of MC activation ability, which caused the hydrogenation of the vinyl group of NS. Pd13Pb9 exhibited the highest chemoselectivity toward AS (92%) among the investigated Pd catalysts. Moreover, RhPb2 exhibited not only high AS selectivity (93%) but also the highest NS conversion (94%) among the investigated catalysts. RhPb2 also exhibited high selectivity toward AS (91%), even when H2 was used as a hydrogen source. Thus, intermetallics that contain Pb, which was the most electronegative metal used in this study, afforded good catalytic performance and were observed to be good catalysts for the chemoselective hydrogenation of NS.
- Furukawa, Shinya,Yoshida, Yurika,Komatsu, Takayuki
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p. 1441 - 1450
(2014/05/20)
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- Combination of palladium and oleic acid coated-magnetite particles: Characterization and using in Heck coupling reaction with magnetic recyclability
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The magnetic Fe3O4 nanoparticles were prepared by co-precipitation method and coated with oleic acid. The oleic acid coated Fe3O4 (Fe@OA) particles were used for the immobilization of palladium particles to prod
- Rafiee, Ezzat,Ataei, Ali,Nadri, Shirin,Joshaghani, Mohammad,Eavani, Sara
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p. 302 - 309
(2013/12/04)
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- Palladium supported on oleic acid-coated magnetic nanoparticle as an efficient catalyst for Heck coupling reaction in aqueous media
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A magnetically recoverable heterogeneous catalyst was synthesized by immobilization of Pd on the surface of oleic acid coated Fe3O4 nanoparticle. This catalyst was used for Heck coupling reaction of styrene with various aryl halides in aqueous media. The catalyst/product separation could be easily achieved with external magnetic field.
- Rafiee, Ezzat,Ataei, Ali,Joshaghani, Mohammad
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p. 707 - 712
(2015/04/14)
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- Stereoselective iron-catalyzed alkyne hydrogenation in ionic liquids
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Iron(0) nanoparticles in ionic liquids (ILs) have been shown to catalyse the semi-hydrogenation of alkynes. In the presence of a nitrile-functionalised IL or acetonitrile, stereoselective formation of (Z)-alkenes was observed. The biphasic solvent system allowed facile separation and re-use of the catalyst. The Royal Society of Chemistry 2014.
- Gieshoff, Tim N.,Welther, Alice,Kessler, Michael T.,Prechtl, Martin H.G.,Jacobi Von Wangelin, Axel
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p. 2261 - 2264
(2014/03/21)
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- A sensitivity tuneable tetraphenylethene-based fluorescent probe for directly indicating the concentration of hydrogen sulfide
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A novel tetraphenylethene-based fluorescent H2S probe was designed and synthesized, which exhibited high selectivity and tuneable sensitivity, making direct indication of H2S concentration in blood and unknown samples possible. This
- Cai, Yunbo,Li, Lingzhi,Wang, Zongtan,Sun, Jing Zhi,Qin, Anjun,Tang, Ben Zhong
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p. 8892 - 8895
(2014/08/05)
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- Palladium supported on zinc oxide nanoparticles: Synthesis, characterization, and application as heterogeneous catalyst for Mizoroki-Heck and Sonogashira reactions under ligand-free and air atmosphere conditions
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In this paper, a novel Palladium (Pd) supported on ZnO nanoparticles was readily synthesized and characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and BET specific surface area measurement. The total amount of palladium particles on ZnO was determined by induced coupled plasma (ICP) analysis and atomic absorption spectroscopy (AAS) which is 9.8 wt%. Percentage of accessible Pd as active catalyst is also estimated to 2.72% based on the thermogravimetric (TG) analysis. Nano Pd/ZnO was found as a new, novel, and excellent heterogeneous catalyst for ligand-free C-C bond formation through the Mizoroki-Heck and Sonogashira reactions under air atmosphere without the use of any Ar or N2 flow. The catalyst can be recovered and recycled several times without marked loss of activity.
- Hosseini-Sarvari, Mona,Razmi, Zahra,Doroodmand, Mohammad Mehdi
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p. 477 - 486
(2014/03/21)
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- Heterogenized cobalt oxide catalysts for nitroarene reduction by pyrolysis of molecularly defined complexes
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Molecularly well-defined homogeneous catalysts are known for a wide variety of chemical transformations. The effect of small changes in molecular structure can be studied in detail and used to optimize many processes. However, many industrial processes require heterogeneous catalysts because of their stability, ease of separation and recyclability, but these are more difficult to control on a molecular level. Here, we describe the conversion of homogeneous cobalt complexes into heterogeneous cobalt oxide catalysts via immobilization and pyrolysis on activated carbon. The catalysts thus produced are useful for the industrially important reduction of nitroarenes to anilines. The ligand indirectly controls the selectivity and activity of the recyclable catalyst and catalyst optimization can be performed at the level of the solution-phase precursor before conversion into the active heterogeneous catalyst.
- Westerhaus, Felix A.,Jagadeesh, Rajenahally V.,Wienhoefer, Gerrit,Pohl, Marga-Martina,Radnik, Joerg,Surkus, Annette-Enrica,Rabeah, Jabor,Junge, Kathrin,Junge, Henrik,Nielsen, Martin,Brueckner, Angelika,Beller, Matthias
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p. 537 - 543
(2013/07/19)
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- Fluorescence response of TICT-active aminostilbenes to copper(II) ions: Redox reaction vs ion recognition
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Cu(II)-selective fluorescence enhancement (1, 2, and 4) or fluorescence quenching (3) was observed for aminostilbenes 1-4 in acetonitrile. The fluorescence responses result from efficient Cu(II)-mediated oxidation of 1-4 that forms new fluorescent species rather than from any specific noncovalent interactions. Evidence of redox reactions includes irreversible Cu(II) titration spectra, spectroscopic observation of the radical cations, and isolation of oxidized aminostilbene dimers. These results provide a new method for synthesis of tetrasubstituted tetrahydrofurans and suggest that aminostilbenes with twisted intramolecular charge-transfer activity are potential fluorescence-enhanced Cu(II) chemodosimeters. The role of Cu(II)-mediated redox reactions should be always taken into account in mechanisms for sensing of arylamine-based Cu(II)-selective fluoroionophores.
- Lin, Cheng-Kai,Yang, Jye-Shane
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- A mild chemoselective Ru-catalyzed reduction of alkynes, ketones, and nitro compounds
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The chemoselective reduction of alkyne, ketones, or nitro groups using (Ph3P)3RuCl2 as an inexpensive catalyst and Zn/water as a stoichiometric reductant is reported. Depending on the nature of the additive and the temperature, good chemoselectivities were observed allowing, e.g., for the selective reduction of a nitro group in the presence of a ketone or an alkyne.
- Schabel, Tobias,Belger, Christian,Plietker, Bernd
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p. 2858 - 2861
(2013/07/19)
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- Z-Stereoselective semi-reduction of alkynes: Modification of the Boland protocol
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Highly Z-selective semi-reduction of alkynes has been achieved by adding TMSCl to a mixture of Zn(Cu/Ag), water, and methanol. The conjugated Z-alkenes have been prepared in high yields at ambient temperature. The formation of isomeric E-alkenes and over-reduction to alkanes were suppressed in our modified Boland reduction protocol. The methodology was extended to the preparation of Z-substituted stilbenes.
- Mohamed, Yasser M.A.,Hansen, Trond Vidar
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p. 3872 - 3877
(2013/06/27)
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- Al-containing mesoporous carbon as effective catalysts for the chemoselective reduction of carbon-carbon double bonds in nitrostilbene derivatives
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A series of Al, Mn, Cu and Fe metal-containing mesoporous carbon catalysts were synthesized for catalyzing selective reduction of carbon-carbon double bond in 4-nitrostilbene analogs bearing nitro group with hydrazine hydrate. The results indicated that the reduction reaction was able to be achieved successfully between carbon-carbon double bond and nitro group. The efficient method has been developed for the reduction of CC double bonds with diimide, catalytically generated in situ from hydrazine hydrate by the synthesized catalysts. The 0.15Al-MC1 as heterogeneous catalyst exhibited the highest catalysis activity and chemoselectivity in all synthesized catalysts. In the presence of 0.15Al-MC1, the reduction of carbon-carbon double bond in 4-nitrostilbene derivatives was up to 99% yield and >99% chemoselectivity at 70 °C in ethanol. On the other hand, the high selective reduction of nitro group in 4-nitrostilbenes was also facile to be achieved with hydrazine hydrate, active carbon and FeCl3·6H2O under inert atmosphere.
- Wang, Liuchang,Zheng, Yanjun,Zhang, Xiquan,Gu, Hongmei,Li, Jiang,Wang, Wei,Li, Baolin
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- Palladium nanoparticles, stabilized by lignin, as catalyst for cross-coupling reactions in water
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Palladium nanoparticles of a definite shape (spherical) and dimension (8-14 and 16-20 nm) were prepared employing two water soluble lignin samples as both reducing and stabilizing agent in definitely green experimental conditions, namely aqueous solution, aerobic conditions, moderate temperature, short times. The above nanoparticles were employed as catalyst for a series of carbon-carbon coupling reactions carried out in water at mild conditions. Heck and Suzuki reactions were performed for several substrates, by changing the nature of halogen, the substituents at the aromatic ring, the bases employed and the temperature. Product yields were satisfactory and selectivities very good. Other two cross-coupling reactions, namely Sonogashira and Stille, were also tested: iodine derivatives showed always the best reactivity, while chlorine derivatives did not react.
- Coccia, Francesca,Tonucci, Lucia,D'Alessandro, Nicola,D'Ambrosio, Primiano,Bressan, Mario
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- Solar energy assisted starch-stabilized palladium nanoparticles and their application in C-C coupling reactions
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Present work reports a novel one step, greener protocol for the synthesis of starch-stabilized palladium nanoparticles (PdNPs) with an average particle diameter of 30-40 nm. These particles were stable and uniform in size. In present protocol, the concentrated solar energy mediated reduction of palladium chloride was achieved by using citric acid as a reducing agent and starch as a capping agent. UV-Visible spectroscopy, Transmission Electron Microscopy, Field Emission Gun-Scanning Electron Microscopy, Selected Area Electron Diffraction and Electron dispersive X-ray Spectral analysis techniques were used to characterize this starch capped PdNPs. Herein; we are reporting such combination of starch and citric acid in the synthesis of PdNPs for the first time. The catalytic activity of synthesized nanoparticles has been checked for Suzuki and Heck cross coupling reactions. The product yield was confirmed by GC. The products were confirmed using GC-MS analysis and also using GC with the help of authentic standards. Solar energy assisted starch stabilized PdNPs showed excellent activity in the C C bond formation between aryl halides (I, Br) with phenyl boronic acid and its derivatives. In addition, the catalyst showed good activity in the Heck coupling reaction of C C bond formation of aryl halides with aromatic alkene. The use of starch, citric acid, water and solar energy makes present protocol greener. Copyright
- Patil, Aniruddha B.,Bhanage, Bhalchandra M.
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p. 5061 - 5068
(2013/08/23)
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- Design of a silver-cerium dioxide core-shell nanocomposite catalyst for chemoselective reduction reactions
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Shelling out: A core-shell nanocomposite comprising an Ag nanoparticle core and a CeO2 nanoparticle shell catalyzes the chemoselective reduction of both nitrostyrenes and epoxides while retaining the C=C bonds (see picture). Reactions with the core-shell structures show greater chemoselectivity than conventional oxide-supported metal nanoparticles.
- Mitsudome, Takato,Mikami, Yusuke,Matoba, Motoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information; experimental part
p. 136 - 139
(2012/02/16)
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