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copper catalyst

Ana I Vicente, Jaime A S Coelho, Svilen P Simeonov, Hristina I Lazarova, Margarita D Popova, Carlos A M Afonso
2,5-Diformylfuran (DFF) is an important biorenewable building block, namely for the manufacture of new polymers that may replace existing materials derived from limited fossil fuel resources. The current reported methods for the preparation of DFF are mainly derived from the oxidation of 5-hydroxymethylfurfural (HMF) and, to a lesser extent, directly from fructose. 5-Chloromethylfurfural (CMF) has been considered an alternative to HMF as an intermediate building block due to its advantages regarding stability, polarity, and availability from glucose and cellulose...
February 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Francesco Balestri, Roberta Moschini, Mario Cappiello, Umberto Mura, Antonella Del-Corso
Bovine lens aldose reductase is susceptible to a copper-mediated oxidation, leading to the generation of a disulfide bridge with the concomitant incorporation of two equivalents of the metal and inactivation of the enzyme. The metal complexed by the protein remains redox active, being able to catalyse the oxidation of different physiological thiol compounds. The thiol oxidase activity displayed by the enzymatic form carrying one equivalent of copper ion (Cu1-AR) has been characterized. The efficacy of Cu1-AR in catalysing thiol oxidation is essentially comparable to the free copper in terms of both thiol concentration and pH effect...
February 21, 2017: Journal of Biological Inorganic Chemistry: JBIC
Ambika Bhagi-Damodaran, Matthew A Michael, Qianhong Zhu, Julian Reed, Braddock A Sandoval, Evan N Mirts, Saumen Chakraborty, Pierre Moënne-Loccoz, Yong Zhang, Yi Lu
Haem-copper oxidase (HCO) catalyses the natural reduction of oxygen to water using a haem-copper centre. Despite decades of research on HCOs, the role of non-haem metal and the reason for nature's choice of copper over other metals such as iron remains unclear. Here, we use a biosynthetic model of HCO in myoglobin that selectively binds different non-haem metals to demonstrate 30-fold and 11-fold enhancements in the oxidase activity of Cu- and Fe-bound HCO mimics, respectively, as compared with Zn-bound mimics...
March 2017: Nature Chemistry
Qian-Qian Zhang, Jing Dong, Yong-Mei Liu, Yong Cao, He-Yong He, Yang-Dong Wang
It was shown for the first time that cyclohexanone oxime (CHO) can be selectively produced by heterogeneous copper-catalyzed hydrogenative transformation of nitrocyclohexane (NC). The combination of Cu(0) and Cu(+) and their cooperative interaction with weakly acidic SiO2 supports elicited a significantly unique and selective catalysis in the hydrogenation of NC to CHO.
February 21, 2017: Chemical Communications: Chem Comm
Porakrit Leophairatana, Sanjoy Samanta, Chathuranga C De Silva, Jeffrey T Koberstein
Alkyne-functional polymers synthesized by ATRP exhibit bimodal molecular weight distributions indicating the occurrence of some undesirable side reaction. By modeling the molecular weight distributions obtained under various reaction condi-tions, we show that the side reaction is alkyne-alkyne (i.e., Glaser) coupling. Glaser coupling accounts for as much as 20 per cent of the polymer produced, significantly compromising the polymer functionality and undermining the success of subse-quent click reactions in which they are used...
February 20, 2017: Journal of the American Chemical Society
Ryosuke Takise, Ryota Isshiki, Kei Muto, Kenichiro Itami, Junichiro Yamaguchi
Because diaryl ethers are present as an important motif in pharmaceuticals and natural products, extensive studies for the development of novel methods have been conducted. A conventional method for the construction of the diaryl ether moiety is the intermolecular cross-coupling reaction of aryl halides and phenols with a copper or palladium catalyst. We developed a catalytic decarbonylative etherification of aromatic esters using a palladium or nickel catalyst with our enabling diphosphine ligand to give the corresponding diaryl ethers...
February 22, 2017: Journal of the American Chemical Society
Jiamei Quan, Takahiro Kondo, Guichang Wang, Junji Nakamura
Energy transfer dynamics of formate (HCOOa ) decomposition on a Cu(110) surface has been studied by measuring the angle-resolved intensity and translational energy distributions of CO2 emitted from the surface in a steady-state reaction of HCOOH and O2 . The angular distribution of CO2 shows a sharp collimation with the direction perpendicular to the surface, as represented by cos(n) θ (n=6). The mean translational energy of CO2 is measured to be as low as 100 meV and is independent of the surface temperature (Ts )...
February 17, 2017: Angewandte Chemie
Ryota Matsuoka, Ryota Sakamoto, Ken Hoshiko, Sono Sasaki, Hiroyasu Masunaga, Kosuke Nagashio, Hiroshi Nishihara
Synthetic two-dimensional polymers, or bottom-up nanosheets, are ultrathin polymeric frameworks with in-plane periodicity. They can be synthesized in a direct, bottom-up fashion using atomic, ionic, or molecular components. However, few are based on carbon-carbon bond formation, which means that there is a potential new field of investigation into these fundamentally important chemical bonds. Here, we describe the bottom-up synthesis of all-carbon, π-conjugated graphdiyne nanosheets. A liquid/liquid interfacial protocol involves layering a dichloromethane solution of hexaethynylbenzene on an aqueous layer containing a copper catalyst at room temperature...
February 15, 2017: Journal of the American Chemical Society
Li Wei, Kunli Goh, Özgür Birer, H Enis Karahan, Jian Chang, Shengli Zhai, Xuncai Chen, Yuan Chen
Electrochemical splitting of water to produce oxygen (O2) and hydrogen (H2) through a cathodic hydrogen evolution reaction (HER) and an anodic oxygen evolution reaction (OER) is a promising green approach for sustainable energy supply. Here we demonstrated a porous nickel-copper phosphide (NiCuP) nano-foam as a bifunctional electrocatalyst for highly efficient total water splitting. Prepared from a bubble-templated electrodeposition method and subsequent low-temperature phosphidization, NiCuP has a hierarchical pore structure with a large electrochemical active surface area...
February 13, 2017: Nanoscale
Carmen Pilar Jiménez-Gómez, Juan A Cecilia, Ramón Moreno-Tost, Pedro Maireles-Torres
Copper species have been incorporated to a mesoporous silica by complexing with amino group of dodecylamine molecules, used as structure-directing agent in the synthesis. A series of Cu/SiO2 catalysts, with copper loadings from 2.5 to 20 wt%, has been synthesized and evaluated in the gas phase hydrogenation of furfural. The most suitable catalytic performance, in terms of 2-methylfuran yield, has been found for intermediate copper content (10 wt%). In this sense, the 10Cu-MS catalyst, at a reaction temperature of 210ºC, after 5 h of time-on-stream, exhibits a 2-methylfuran yield higher than 95 mol%, with a H2:FUR molar ratio of 11...
February 6, 2017: ChemSusChem
Anbu Nagaraj, Dhakshinamoorthy Amarajothi
In the present work, Friedel-Crafts alkylation reaction of indole with β-nitrostyrene is examined using a readily available copper based metal-organic frameworks (MOFs) namely, Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylic acid) as solid catalyst under mild reaction conditions. Among the various catalysts screened for this reaction, Cu3(BTC)2 exhibits higher activity under the optimized reaction conditions. Besides the absence of leaching of active sites, it is also observed that the catalyst can be reused for four cycles with a minimal decrease in its activity...
May 15, 2017: Journal of Colloid and Interface Science
Wentao Xue, Jie Wang, Ming Wen, Gaojian Chen, Weidong Zhang
The successful chain-growth copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization employing Cu(0)/pentamethyldiethylenetriamine (PMDETA) and alkyl halide as catalyst is first investigated by a combination of nuclear magnetic resonance, gel-permeation chromatography, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In addition, the electron transfer mediated "click-radical" concurrent polymerization utilizing Cu(0)/PMDETA as catalyst is successfully employed to generate well-defined copolymers, where controlled CuAAC polymerization of clickable ester monomer is progressed in the main chain acting as the polymer backbone, the controlled radical polymerization (CRP) of acrylic monomer is carried out in the side chain...
February 3, 2017: Macromolecular Rapid Communications
Pablo Ortiz, Juan F Collados, Ravindra P Jumde, Edwin Otten, Syuzanna R Harutyunyan
Inexpensive and readily available organomagnesium reagents were used for the catalytic enantioselective alkylation of enolizable N-sulfonyl ketimines. The low reactivity and competing enolization of the ketimines was overcome by the use of a copper-phosphine chiral catalyst, which also rendered the transformation highly chemoselective and enantioselective for a broad range of ketimine substrates.
February 3, 2017: Angewandte Chemie
Patrick Tomkins, Marco Ranocchiari, Jeroen A van Bokhoven
In the recent years methane has become increasingly abundant. However, transportation costs are high and methane recovered as side product is often flared rather than valorized. The chemical utilization of methane is highly challenging and currently mainly based on the cost-intensive production of synthesis gas and its conversion. Alternative routes have been discovered in academia, though high temperatures are mostly required. However, the direct conversion of methane to methanol is an exception. It can already be carried out at comparably low temperatures...
February 2, 2017: Accounts of Chemical Research
Valentín Hornillos, Sureshbabu Guduguntla, Martín Fañanás-Mastral, Manuel Pérez, Pieter H Bos, Alena Rudolph, Syuzanna R Harutyunyan, Ben L Feringa
This protocol describes a method for the catalytic enantioselective synthesis of tertiary and quaternary carbon stereogenic centers, which are widely present in pharmaceutical and natural products. The method is based on the direct reaction between organolithium compounds, which are cheap, readily available and broadly used in chemical synthesis, and allylic electrophiles, using chiral copper catalysts. The methodology involves the asymmetric allylic alkylation (AAA) of allyl bromides, chlorides and ethers with organolithium compounds using catalyst systems based on Cu-Taniaphos and Cu-phosphoramidites...
March 2017: Nature Protocols
Sanoop Paulose, Rajeev Raghavan, Benny K George
Reactivity is of great importance for metal oxide nanoparticles (MONP) used as catalysts and advanced materials, but seeking for higher reactivity seems to be conflict with high chemical stability required for MONP. There is direct balance between reactivity and stability of these MONP. This could be acheived for metal oxide by dispersing them in a substrate. Here, we report a simple, efficient and high-yield process for the production of copper oxide (CuO) nanoparticles dispersed on a chemically inert material, few-layer hexagonal boron nitride (h-BN) with a thickness around 1...
May 15, 2017: Journal of Colloid and Interface Science
David Lennon, John M Winfield
Aspects of the chemistry of selected metal fluorides, which are pertinent to their real or potential use as Lewis acidic, heterogeneous catalysts, are reviewed. Particular attention is paid to β-aluminum trifluoride, aluminum chlorofluoride and aluminas γ and η, whose surfaces become partially fluorinated or chlorinated, through pre-treatment with halogenating reagents or during a catalytic reaction. In these cases, direct comparisons with nanostructured metal fluorides are possible. In the second part of the review, attention is directed to iron(III) and copper(II) metal chlorides, whose Lewis acidity and potential redox function have had important catalytic implications in large-scale chlorohydrocarbons chemistry...
January 28, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Hoda Keipour, Angela Jalba, Léo Delage-Laurin, Thierry Ollevier
An efficient copper-catalyzed carbenoid insertion reaction of α-diazo carbonyl compounds into Si-H and S-H bonds was developed. A wide range of α-silylesters and α-thioesters was obtained in high yields (up to 98%) from α-diazoesters using 5 mol % of a simple copper(I) salt as catalyst. Using 0.05 mol % of the same catalyst, α-diazoketones led to α-silylketones in low to good yields (up to 70%).
January 28, 2017: Journal of Organic Chemistry
María Luisa Cerón, Mònica Calatayud
A comparative theoretical study applying Dual Descriptor has been performed using Water Gas Shift reaction, catalyzed by copper supported on monoclinic and tetragonal zirconia. The Dual Descriptor and thermodynamic considerations were used to understand the structural effects that occur in the reaction when it is catalyzed by C u on both zirconia phases. It was found that the formation of carbonates in the C u supported on tetragonal zirconia dehydrogenates consistently with experimental results.
February 2017: Journal of Molecular Modeling
Pan Dang, Zhilei Zheng, Yun Liang
The sulfuration reaction of 2-(2-iodobenzoyl) substituted, or 2-(2-iodobenzyl) substituted 1,2,3,4-tetrahydroisoquinolines with potassium sulfide proceeded in the presence of copper catalysts to give tetrahydroisoquinoline-fused 1,3-benzothiazine scaffolds in moderate to appropriate yields. This protocol provided an efficient and simple strategy to construct the corresponding benzothiazine derivatives via formation of C(sp(3))-S bond and C(sp(2))-S bond, which the C-S bonds formed via different routes in this reaction (traditional cross-coupling reaction via the cleavage of C-I bond and oxidative cross-coupling reaction via C(sp(3))-H bond functionalization)...
February 1, 2017: Journal of Organic Chemistry
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