Wang J.,Xiamen University |
Wang J.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Chernavskii P.A.,Moscow State University |
Khodakov A.Y.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Wang Y.,Xiamen University
Journal of Catalysis | Year: 2012
The structure of alumina-supported copper-cobalt catalysts prepared by incipient co-impregnation was studied by using a combination of various characterization techniques including in situ XRD, XPS, TPR, XANES/EXAFS, in situ magnetic method, and TEM. The results suggest a much higher dispersion of copper than cobalt on γ-Al 2O 3 and a stronger interaction between cobalt and copper oxide particles, leading to the formation of mixed copper-cobalt oxides in the calcined catalysts. Cobalt reduction was significantly enhanced in the presence of copper. Furthermore, our characterizations indicate the formation of bimetallic Cu-Co particles in the reduced catalysts and enrichment of the surface of bimetallic particles with Cu. The catalytic studies showed dramatic modifications of both the rate and selectivity in the hydrogenation of CO after addition of even small amounts of Cu to supported Co catalysts. The presence of Cu increased the selectivity to alcohols by an order of magnitude and decreased the overall carbon monoxide conversion. Structure-performance correlations suggest that the Cu-Co bimetallic particles may be involved in higher alcohol synthesis. © 2011 Elsevier Inc. All rights reserved.
Bonin H.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Sauthier M.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Felpin F.-X.,University of Nantes
Advanced Synthesis and Catalysis | Year: 2014
This review gives an overview of the generation of aryl radicals, mediated by transition metals, and their use for the C-H arylation of heteroarenes. The different sources of aromatic derivatives able to generate aryl radicals via a metal-assisted reduction or oxidation are discussed, with a critical view of the developed systems. The radical arylations of nitrogen-, oxygen- or sulfur-containing heterocycles are then described and mechanistic considerations are discussed as well. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Bonin H.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Fouquet E.,CNRS Institute of Molecular Sciences |
Felpin F.-X.,CNRS Institute of Molecular Sciences |
Felpin F.-X.,University of Nantes
Advanced Synthesis and Catalysis | Year: 2011
This review gives an overview of the use of unusual diazonium and iodonium salts as electrophiles for the Suzuki-Miyaura reaction. The discussion mainly focuses, with a critical view, on catalytic systems developed with these electrophiles. The review also discusses their general properties and preparation as well as mechanistic aspects. A last and brief comparison of diazonium versus iodonium salts, by highlighting advantages and drawbacks of both, gives the reader an understandable resumé. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Granger P.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Parvulescu V.I.,University of Bucharest
Chemical Reviews | Year: 2011
Important results reported on three-way and lean-burn DeNOx catalysts, demonstrating the added value of surface science and molecular modeling investigations, are reviewed. DeNOx systems are found to enable much lower fuel consumption level and for this the NOx control would be more probably centered on further improvement of the selective catalytic reduction performances. The emissions of N2O are not actually regulated in Europe but might be considered in the future. This implies development of intrinsically active and selective catalytic systems to lower outlet NO emission and also to reduce the steric hindrance of end-of-pipe systems. Recent work demonstrates that Cu:SAPO-5 and Cu:SAPO-11 synthesized using hydrothermal ion exchange method led to a 6-fold increased Cu incorporation and to an increased stability of copper as bidentate Cu species that might represent a significant breakthrough compared to previous attempts.
Abraham F.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Arab-Chapelet B.,CEA Marcoule Nuclear Site |
Rivenet M.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Tamain C.,CEA Marcoule Nuclear Site |
Grandjean S.,CEA Marcoule Nuclear Site
Coordination Chemistry Reviews | Year: 2014
Actinide oxalates are an important class of materials mainly for the nuclear industry. This review presents the crystal growth methods addressed to non-soluble actinide (III) and (IV) oxalates and to soluble actinyl oxalates. Actinide-oxalate discrete ions, one-dimensional coordination polymers and two- or three-dimensional frameworks are described for the different oxidation states of actinides in simple, double or triple actinide oxalates together with mixed actinide (IV)-lanthanide (III) or -actinide (III) and mixed ligands actinide oxalates. The main applications of actinide oxalates, particularly for radioactive waste management and nuclear fuel treatment and recycling are also reported. © 2013 Elsevier B.V.
Vanbesien T.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Monflier E.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Hapiot F.,CNRS Laboratory of Catalysis and Solid State Chemistry
ACS Catalysis | Year: 2015
Naturally occurring triglycerides have been hydroformylated through supramolecular means in the presence of cyclodextrins (CDs). During the course of the reaction, a transient supramolecular complex is formed between triglyceride alkyl chains and the appropriate CDs in a well-defined concentration range. The resulting CD/triglyceride supramolecular emulsifiers help convert the triglyceride Cî - ?C double bonds in biphasic conditions using a water-soluble organometallic catalyst. The catalytic system could be efficiently recycled. © 2015 American Chemical Society.
Biot C.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Biot C.,Lille University of Science and Technology |
Dive D.,University of Lille Nord de France
Topics in Organometallic Chemistry | Year: 2010
This chapter summarizes recent developments in the design, synthesis, and structure-activity relationship studies of organometallic antimalarials. It begins with a general introduction to malaria and the biology of the parasite Plasmodium falciparum, with a focus on the heme detoxification system. Then, a number of metal complexes from the literature are reported for their antiplasmodial activity. The second half of the chapter deals with the serendipitous discovery of ferroquine, its mechanism(s) of action, and the failure to induce a resistance. Last, but not least, we suggest that the bioorganometallic approach offers the potential for the design of novel therapeutic agents. © 2010 Springer-Verlag Berlin Heidelberg.
Hammaecher C.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Paul J.-F.,CNRS Laboratory of Catalysis and Solid State Chemistry
Journal of Catalysis | Year: 2013
Lactic acid adsorption and dehydration toward acrylic acid processes have been studied by means of density functional theory (DFT) calculations on 0 1 1, 1̄01, and 1̄11 monoclinic zirconia surfaces. Lactic acid presents two function types (carboxylic acid and alcohol). Therefore, seven modes of monodentate or bidentate adsorption have been characterized on the potential energy surfaces. Lactic acid is preferentially stabilized in a bidentate bridging mode with O-H bond dissociation whatever the studied surface. For the lactic acid dehydration reaction, two mechanisms have been studied. The carbocation formation by direct C-OH breaking proceeds with a very high activation energy ranging from 2.54 to 3.10 eV depending on the surface. On the contrary, lattice oxygen atoms can easily abstract a hydrogen atom from the methyl group of the lactic acid, and this reaction leads to carbanion formation with a lower activation energy ranging from 1.09 to 1.29 eV. Therefore, this mechanism could be a part of acrylic acid formation.
Olchowka J.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Falaise C.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Volkringer C.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Henry N.,CNRS Laboratory of Catalysis and Solid State Chemistry |
Loiseau T.,CNRS Laboratory of Catalysis and Solid State Chemistry
Chemistry - A European Journal | Year: 2013
The hydrothermal reactions of uranyl nitrate and metallic copper with aromatic polycarboxylic acids gave rise to the formation of five heterometallic UO2 2+-Cu2+ coordination polymers: (UO 2)Cu(H2O)2(1,2-bdc)2 (1; 1,2-bdc=phthalate), (UO2)Cu(H2O)2(btec)×4 H2O (2) and (UO2)Cu(btec) (2′; btec=pyromellitate), (UO2)2Cu(H2O)4(mel) (3; mel=mellitate), and (UO2)2O(OH)2Cu(H 2O)2(1,3-bdc)×H2O (4; 1,3-bdc=isophthlalate). Single-crystal X-ray diffraction (XRD) analysis of compound 1 revealed 2D layers of chains of UO8 and CuO 4(H2O)2 units that were connected through the phthalate ligands. In compound 2, these sheets were connected to each other through the two additional carboxylate arms of the pyromellitate, thus resulting in a 3D open-framework with 1D channels that trapped water molecules. Upon heating, free and bonded water species (from Cu-OH2) were evacuated from the structure. This thermal transition was followed by in situ XRD and IR spectroscopy. Heating induced a solid-state topotactic transformation with the formation of a new set of Cu-O interactions in the crystalline anhydrous structure (2′), in order to keep the square-planar environment around the copper centers. The structure of compound 3 was built up from trinuclear motifs, in which one copper center, CuO4(OH2)2, was linked to two uranium units, UO5(H2O)2. The assembly of this trimer, "U2Cu", with the mellitate generated a 3D network. Complex 4 contained a tetranuclear uranyl core of UO5(OH)2 and UO6(OH) units that were linked to two copper centers, CuO(OH)2(H2O)2, which were then connected to each other through isophthalate ligands and U=O-Cu interactions to create a 3D structure. The common structural feature of these different compounds is a bridging oxo group of U=O-Cu type, which is reflected by apical Cu-O distances in the range 2.350(3)-2.745(5) Å. In the case of a shorter Cu-O distance, a slight lengthening of the uranyl bond (U=O) is observed (e.g., 1.805(3) Å in complex 4). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ghelamallah M.,University of Mascara |
Granger P.,CNRS Laboratory of Catalysis and Solid State Chemistry
Fuel | Year: 2012
The dry reforming of CH 4 by CO 2 has been studied, between 300 and 900°C, over monometallic platinum and rhodium based catalysts supported on α-Al 2O 3 doped with La 2O 3 and BaO. Those catalysts were prepared by conventional wet impregnation and characterized by various physicochemical techniques (nitrogen adsorption, X-ray diffraction, XPS analysis and H 2- temperature-programmed experiments). It was found that Pt and Rh incorporation leads to different types of interactions with La and Ba-modified α-Al 2O 3. As observed, Pt would preferentially interact with Ba inducing an inhibiting effect on the rate of the CH 4/CO 2 reaction reflected by a significant increase in the apparent activation energy. On the other hand, the preferential interaction of Rh with lanthanum oxide after Ba incorporation leads to the preservation of the catalyst activity. Such changes in catalytic properties have been discussed in the light of surface characterization and previous mechanistic information related to the occurrence of a bi-functional mechanism involving the metal/support interface. © 2012 Elsevier Ltd. All rights reserved.