ChemCatChem

Cover image for Vol. 4 Issue 5

May 2012

Volume 4, Issue 5

Pages 569–707

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
    9. Full Papers
    10. Preview
    1. Cover Picture: (ChemCatChem 5/2012) (page 569)

      Article first published online: 24 APR 2012 | DOI: 10.1002/cctc.201290012

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      Qualification and Quantification of Reduced Sites Quantification of spin concentration by electron paramagnetic resonance (EPR) is a complicated issue, in particular if overlapping contributions of different paramagnetic centers exist. This problem can be overcome by using high-frequency EPR, by which contributions with different g values can be disentangled. This approach is similar to the use of ever increasing magnetic fields in NMR spectroscopy. Double integration of the EPR spectrum results in step-like features, familiar to those seen in NMR spectroscopy, which permits a direct readout of relative spin concentrations. Invoking an external or internal spin standard like Mn2+, it is also possible to determine the absolute spin concentration. This method was applied for the qualification and quantification of reduced sites on supported vanadium oxide catalysts used for sample reactions, such as the oxidative dehydrogenation of propane or deep reduction with propane or hydrogen. The data show the important influence of the support material on the type of potentially active sites and the degree of reduction obtained.

  2. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
    9. Full Papers
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    1. Graphical Abstract: ChemCatChem 5/2012 (pages 571–576)

      Article first published online: 24 APR 2012 | DOI: 10.1002/cctc.201290013

  3. News

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
    9. Full Papers
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  4. Concept

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
    9. Full Papers
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    1. Operando Studies of Catalyst Surfaces during Catalysis and under Reaction Conditions: Ambient Pressure X-Ray Photoelectron Spectroscopy with a Flow-Cell Reactor (pages 583–590)

      Prof. Dr. Franklin (Feng) Tao

      Article first published online: 19 APR 2012 | DOI: 10.1002/cctc.201200002

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      Keeping the pressure on: A new in-house ambient pressure X-ray spectroscopy technique (AP-XPS) using a bench-top X-ray source that can study surfaces of catalysts in a gaseous environment of tens of Torr up to 500–550 °C.

  5. Review

    1. Top of page
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    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
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    1. Biocatalyzed Regio- and Chemoselective Ester Cleavage: Synthesis of Bioactive Molecules (pages 592–608)

      Dr. Efrosini Barbayianni and Prof. George Kokotos

      Article first published online: 18 APR 2012 | DOI: 10.1002/cctc.201200035

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      A matter of choice: Biocatalysts are versatile tools in organic synthesis for regio- and chemoselective transformations. Particularly lipases and esterases can preferentially cleave carboxylic esters, depending on their nature or their position on a complex molecule. This review aims to highlight selected examples, where biocatalysis has been used for the regio- and chemoselective cleavage of carboxylic esters in various categories of structurally different bioactive natural products and synthetic molecules.

  6. Highlights

    1. Top of page
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    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
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    1. New Strategies for CO2-to-Methanol Conversion (pages 609–611)

      Dr. Joyanta Choudhury

      Article first published online: 2 MAR 2012 | DOI: 10.1002/cctc.201100495

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      Just two steps: Two new strategies with regard to the “methanol economy” proposal have been developed: an indirect CO2-derivative-to-methanol conversion by means of a metal ligand cooperative catalysis and a stepwise CO2-to-methanol conversion via cascade catalysis. These represent a significant scientific development with respect to the current on-going challenges on energy and fuel for a sustainable future.

    2. Oxidative Enamine Catalysis: Direct Catalytic Enantioselective β-Functionalization of Aldehydes (pages 612–615)

      Prof. Jian Xiao

      Article first published online: 14 MAR 2012 | DOI: 10.1002/cctc.201100488

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      Jekyll and aldeHyde: The oxidation of enamines to iminium species by 2-iodoxybenzoic acid (IBX) or 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) catalyzed by a chiral secondary amine catalyst enabled the unprecedented enantioselective β-functionalization of aldehydes with various nucleophiles in high stereoselectivity.

  7. Communications

    1. Top of page
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    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
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    1. Lipase Catalyzed In Situ Production of Acetaldehyde: A Controllable and Mild Strategy for Multi-Step Reactions (pages 617–619)

      María Pérez-Sánchez and Dr. Pablo Domínguez de María

      Article first published online: 16 MAR 2012 | DOI: 10.1002/cctc.201100493

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      Know-how for a new use: Lipase-catalyzed reactions with vinyl esters form acetaldehyde as by-product. A controllable in situ production of a useful, but highly reactive substrate can allow multi-step reactions. As example, the first lipase-lyase one-pot combination is reported.

    2. Photooxidation of Sulfides to Sulfoxides Mediated by Tetra-O-Acetylriboflavin and Visible Light (pages 620–623)

      Jitka Dad'ová, Dr. Eva Svobodová, Dr. Marek Sikorski, Prof. Dr. Burkhard König and Dr. Radek Cibulka

      Article first published online: 27 MAR 2012 | DOI: 10.1002/cctc.201100372

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      Chemoselective photooxidation: Tetra-O-acetylriboflavin and blue light mediate the selective oxidation of sulfides to sulfoxides without overoxidation to sulfones. Reaction is very effective in ethanol/water (95:5,v/v) mixture reaching a quantum yield of Φ=0.60. The photooxidation reaction scope includes aliphatic and aromatic sulfides including sterically hindered substrates.

    3. In Situ FT-IR Studies on Catalytic Nature of Iron Nitride: Identification of the N Active Site (pages 624–627)

      Dr. Li Wang, Prof. Qin Xin, Yue Zhao, Ge Zhang, Jie Dong, Prof. Weimin Gong and Prof. Hongchen Guo

      Article first published online: 30 MAR 2012 | DOI: 10.1002/cctc.201100311

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      Not only aliens probe: Iron nitride plays an important role in many catalytic processes, such as Haber–Bosch process, for which knowledge of surface catalytic properties is vital. By using FTIR spectroscopic techniques, this work describes the surface active sites of iron nitride/fumed SiO2 by coupled with CO, NH3, and H2 as probe- molecules. Interestingly, the chemically active N site is observed in addition to Fe site.

    4. Controlled Photocatalytic Oxidation of Benzene in Aqueous Clay Suspension (pages 628–630)

      Dr. Yusuke Ide, Mizuki Matsuoka and Prof. Dr. Makoto Ogawa

      Article first published online: 30 MAR 2012 | DOI: 10.1002/cctc.201200043

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      Keeping oxidation in suspense: Photocatalytic oxidation efficiency of aqueous benzene on TiO2 was enhanced by conducting the reaction in an aqueous suspension of TiO2 and clay mineral.

    5. Imaging the Profiles of Deactivating Species on the Catalyst used for the Cracking of Waste Polyethylene by Combined Microscopies (pages 631–635)

      Dr. Pedro Castaño, Dr. Gorka Elordi, Prof. Martin Olazar and Prof. Javier Bilbao

      Article first published online: 30 MAR 2012 | DOI: 10.1002/cctc.201100506

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      Profiling a catalyst: In this work, we report the profiles of deactivating species (coke) along the catalyst used in the cracking of waste polyethylene, using combined visible, FTIR, and Raman microscopies. The results show a gradient of concentration of aromatic and aliphatic structures within the particles.

    6. Hole Localization and Thermochemistry of Oxidative Dehydrogenation of Aqueous Rutile TiO2(110) (pages 636–640)

      Dr. Jun Cheng, Dr. Marialore Sulpizi, Dr. Joost VandeVondele and Prof.Dr. Michiel Sprik

      Article first published online: 16 MAR 2012 | DOI: 10.1002/cctc.201100498

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      An ode to free energy: Oxidative dehydrogenation (ODH) of water on aqueous TiO2 is studied using density functional theory based molecular dynamics. Hole localization is found to be crucial to decrease the high cost of ODH. Separating into deprotonation and ionization reveals that the ODH energy is dominated by oxidation energy. Comparison to the free energies in bulk water suggests that the activation of water ODH by TiO2 is almost entirely attributable to an increase in acidity.

  8. Full Papers

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
    9. Full Papers
    10. Preview
    1. Characterization and Quantification of Reduced Sites on Supported Vanadium Oxide Catalysts by Using High-Frequency Electron Paramagnetic Resonance (pages 641–652)

      Dr. Arne Dinse, Carlos Carrero, Dr. Andrzej Ozarowski, Prof. Reinhard Schomäcker, Prof. Robert Schlögl and Prof. Klaus-Peter Dinse

      Article first published online: 30 MAR 2012 | DOI: 10.1002/cctc.201100412

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      A super model on the catalyst walk: V2O5 catalysts supported by SBA-15, Al2O3, or TiO2 are exposed to the oxidative dehydrogenation of propane, pure hydrogen and propane and characterized by using high-frequency electron paramagnetic resonance. The abundance of paramagnetic V4+ and Ti3+ species in the catalysts is studied. The two-parameter model helps rationalize the dual influences of reducibility and local structure of redox-active sites.

    2. Cascade Coupling of Ene Reductases with Alcohol Dehydrogenases: Enantioselective Reduction of Prochiral Unsaturated Aldehydes (pages 653–659)

      Prof. Elisabetta Brenna, Dr. Francesco G. Gatti, Dr. Daniela Monti, Fabio Parmeggiani and Dr. Alessandro Sacchetti

      Article first published online: 28 FEB 2012 | DOI: 10.1002/cctc.201100418

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      Hear O'YE, hear O'YE! The combination of the in situ substrate feeding product removal technology with a multienzymatic cascade system (old yellow enzyme and horse liver alcohol dehydrogenase) increased both the yields and enantioselectivities in the reduction of α-substituted cinnamaldehydes.

    3. Silica Based Cocatalysts for Heterogeneous Olefin Dimerization and Ethene Polymerization Reactions with Nickel Complexes (pages 660–667)

      Dr. Matthias Dötterl and Prof. Dr. Helmut G. Alt

      Article first published online: 27 MAR 2012 | DOI: 10.1002/cctc.201100484

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      Buffered cocatalysts get selective: In combination with triphenylbismuth or N-methylpyrrole buffers, EtAlCl2 and Et2AlCl surface-modified silicas are employed as heterogeneous cocatalysts of nickel complexes to catalyze selective olefin dimerization and polymerization reactions. Surface-modified silica is coated with a BiPh3-buffered chloroaluminate ionic liquid to give a supported ionic liquid phase (SILP) cocatalyst.

    4. Promotional Effect of Ni in the Selective Gas-Phase Hydrogenation of Chloronitrobenzene over Cu-based Catalysts (pages 668–673)

      Dr. Fernando Cárdenas-Lizana, Blaise Bridier, Choong Catherine Kai Shin, Prof. Javier Pérez-Ramírez and Prof. Dr. Lioubov Kiwi-Minsker

      Article first published online: 1 MAR 2012 | DOI: 10.1002/cctc.201100470

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      Double or quits! The incorporation of Ni in Cu[BOND]Al (atomic Cu/Ni/Al ratio 2.75:0.25:1) catalyst derived from a hydrotalcite precursor served to double activity in the hydrogenation of p-chloronitrobenzene, with p-chloroaniline as the only reaction product.

    5. Mesoporous Silica Nanoparticle-Stabilized and Manganese-Modified Rhodium Nanoparticles as Catalysts for Highly Selective Synthesis of Ethanol and Acetaldehyde from Syngas (pages 674–680)

      Dr. Yulin Huang, Dr. Weihua Deng, Enruo Guo, Dr. Po-Wen Chung, Senniang Chen, Dr. Brian G. Trewyn, Prof. Dr. Robert C. Brown and Prof. Dr. Victor S.-Y. Lin

      Article first published online: 30 MAR 2012 | DOI: 10.1002/cctc.201100460

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      Up close and ethanol: Mesoporous silica nanoparticle (MSN)-supported rhodium nanoparticles (≈2 nm) are encapsulated in situ and stabilized during the synthesis of the mesoporous material. In CO hydrogenation, the carbon selectivity for C2 oxygenates (including ethanol and acetaldehyde) is unprecedentedly high at 74.5 % with a very small amount of methanol produced if Rh nanoparticles are modified by manganese oxide with very close interaction.

    6. Dehydroalkylation of Benzene with Ethane over Pt/H-MFI in the Presence of Hydrogen Scavengers (pages 681–686)

      Dr.  V. V. Ordomskiy, L. I. Rodionova, Prof. Dr.  I. I. Ivanova and Dr.  F. Luck

      Article first published online: 16 MAR 2012 | DOI: 10.1002/cctc.201100445

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      Scavenging for hydrogen: The alkylation of benzene with ethane over the Pt/H-MFI catalyst in the presence of hydrogen scavengers is studied. The addition of Ti, Zr2Fe, or ZrV2 leads to an increase in ethane conversion by 5–7 times. The positive effect increases with pressure and content of scavengers. The conversion decreases with time on stream because of the saturation of hydrogen acceptors.

    7. Tailor-Made Mesoporous Ti-SBA-15 Catalysts for Oxidative Desulfurization of Refractory Aromatic Sulfur Compounds in Transport Fuel (pages 687–697)

      Dr. Tae-Wan Kim, Min-Ji Kim, Prof. Freddy Kleitz, Mahesh Muraleedharan Nair, Rémy Guillet-Nicolas, Dr. Kwang-Eun Jeong, Dr. Ho-Jeong Chae, Dr. Chul-Ung Kim and Dr. Soon-Yong Jeong

      Article first published online: 6 MAR 2012 | DOI: 10.1002/cctc.201100417

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      Desulfurization of sour heavy crude is essential to produce clean petroleum products with ultra-low sulfur content, in line with global environmental mandates. Large-pore Ti-SBA-15 materials are the most suitable catalysts for selective oxidative desulfurization of both model S-containing compounds and industrial diesel fuel. Structural and compositional parameters of the materials are critical in the synthetic design of new optimized catalysts with extended lifetimes.

    8. Catalyst Recovery and Recycling Facilitated by Magnetic Separation: Iridium and Other Metal Nanoparticles (pages 698–703)

      Marcos J. Jacinto, Fernanda P. Silva, Pedro K. Kiyohara, Richard Landers and Liane M. Rossi

      Article first published online: 1 MAR 2012 | DOI: 10.1002/cctc.201100415

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      Nanoparticle separation made easy: The immobilization of metal nanoparticles on magnetic responsive solids allows the easy, fast, and clean separation of catalysts. The immobilization process is facilitated by functionalizing the support surface with amino groups. Iridium, rhodium, and platinum nanoparticle catalysts are highly active and easily recycled.

  9. Preview

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Review
    7. Highlights
    8. Communications
    9. Full Papers
    10. Preview
    1. You have free access to this content
      Preview: ChemCatChem 6/2012 (page 707)

      Article first published online: 24 APR 2012 | DOI: 10.1002/cctc.201290015

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