Chemistry - A European Journal

Cover image for Vol. 17 Issue 10

March 1, 2011

Volume 17, Issue 10

Pages 2789–3035

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. Cover Picture: A Tetragonal 2D Array of Single-Molecule Magnets with Modulated Collective Behavior (Chem. Eur. J. 10/2011) (page 2789)

      Enrique Burzurí, Dr. Javier Campo, Prof. Larry R. Falvello, Elena Forcén-Vázquez, Dr. Fernando Luis, Isabel Mayoral, Prof. Fernando Palacio, Cristina Sáenz de Pipaón and Dr. Milagros Tomás

      Version of Record online: 22 FEB 2011 | DOI: 10.1002/chem.201190044

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      Aqueous chemistry has produced an anionic square net of cobalt citrate cubane single molecule magnets (SMMs) interleaved with a secondary magnetic network of bridging octahedrally coordinated CoII. The magnetic response of this system, which varies with a change in its solid environment, suggests novel possibilities for magnetically active SMM polymers, accessible through wet chemistry. For more details, see the Communication by L. R. Falvello and F. Palacio et al. on page 2818 ff.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
    8. Full Papers
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    1. Inside Cover: A Chromo-Fluorogenic Tetrazole-Based CoBr2 Coordination Polymer Gel as a Highly Sensitive and Selective Chemosensor for Volatile Gases Containing Chloride (Chem. Eur. J. 10/2011) (page 2790)

      Hyejin Lee, Sung Ho Jung, Dr. Won Seok Han, Jong Hun Moon, Sunwoo Kang, Prof. Dr. Jin Yong Lee, Prof. Dr. Jong Hwa Jung and Prof. Dr. Seiji Shinkai

      Version of Record online: 22 FEB 2011 | DOI: 10.1002/chem.201190045

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      Toxic, volatile gases that contain chloride are detected by a tetrazole-based coordination polymer gel with CoBr2. Photophysical studies showed that the coordination polymer gel exhibits a typical π–π* transition resulting in highly fluorescent behavior. The results suggest that coordination polymer gels may offer useful applications in chemical sensing. For more details see the Communication by J. H. Jung, J. Y. Lee, S. Shinkai et al. on page 2823 ff.

  3. Graphical Abstract

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

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

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
    8. Full Papers
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    1. Natural Products

      Chemical Ecology of Tannins: Recent Developments in Tannin Chemistry Reveal New Structures and Structure–Activity Patterns (pages 2806–2816)

      Prof. Dr. Juha-Pekka Salminen, Dr. Maarit Karonen and Dr. Jari Sinkkonen

      Version of Record online: 9 FEB 2011 | DOI: 10.1002/chem.201002662

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      Underestimated molecules and activities: Modern time-of-flight mass spectrometry has revealed undecameric ellagitannin molecules from plants, although the detection barrier was previously limited to the pentamer range. These complex, but largely ignored natural compounds may possess important anti-herbivore activities that are triggered via oxidation reactions in the alkaline gut of insect herbivores (see scheme).

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
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    1. Magnetism

      A Tetragonal 2D Array of Single-Molecule Magnets with Modulated Collective Behavior (pages 2818–2822)

      Enrique Burzurí, Dr. Javier Campo, Prof. Larry R. Falvello, Elena Forcén-Vázquez, Dr. Fernando Luis, Isabel Mayoral, Prof. Fernando Palacio, Cristina Sáenz de Pipaón and Dr. Milagros Tomás

      Version of Record online: 10 FEB 2011 | DOI: 10.1002/chem.201002980

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      The counterion makes a difference: A square 2D array of cobalt citrate cubanes linked by bridging six-coordinate cobalt atoms (see graphic) displays collective magnetic behavior, which changes with subtle differences in the crystalline surroundings. The magnetic properties of two solid modifications, both synthesized by using wet chemistry techniques, reveal two different relaxation processes in each system at low temperatures, each with its own timescale.

    2. Sensors

      A Chromo-Fluorogenic Tetrazole-Based CoBr2 Coordination Polymer Gel as a Highly Sensitive and Selective Chemosensor for Volatile Gases Containing Chloride (pages 2823–2827)

      Hyejin Lee, Sung Ho Jung, Dr. Won Seok Han, Jong Hun Moon, Sunwoo Kang, Prof. Dr. Jin Yong Lee, Prof. Dr. Jong Hwa Jung and Prof. Dr. Seiji Shinkai

      Version of Record online: 10 FEB 2011 | DOI: 10.1002/chem.201003279

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      Catching chloride: A tetrazole-based ligand without long alkyl chains is used to form a coordination polymer gel with CoBr2 (1). Gel 1 has a spherical structure with a 20–30 nm diameter. More interestingly, gel 1 selectively recognizes toxic gases, such as HCl, SOCl2, (COCl)2, and COCl2 that contain chloride atoms.

    3. Crystal Growth

      In Vitro Repair of a Biomineral with a Mesocrystal Structure (pages 2828–2832)

      Misako Kijima, Dr. Yuya Oaki and Prof. Hiroaki Imai

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201003203

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      How to repair a seashell: A partially etched biomineral, namely, the prismatic layer of a seashell, has been repaired in a synthetic system. The oriented nanocrystals and the macroscopic morphologies, with the same specific crystallographic orientation as the original part, can be regenerated through an in vitro repair process (see graphic).

    4. Hydrogen Bonding

      Unraveling Low-Barrier Hydrogen Bonds in Complex Systems with a Simple Quantum Topological Criterion (pages 2833–2837)

      Robin Chaudret, Dr. G. Andrés Cisneros, Dr. Olivier Parisel and Dr. Jean-Philip Piquemal

      Version of Record online: 9 FEB 2011 | DOI: 10.1002/chem.201002978

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      A simple quantum chemical approach to characterize low-barrier hydrogen bonds with the electron localization function topological analysis has been proposed. Various systems, from protonated water dimers to the full phosphorescent yellow protein, have been described. In both cases, a V(H) basin appears (see graphic).

    5. Cyclization Reactions

      Gold(I)-Catalyzed, Highly Diastereoselective, Tandem Heterocyclizations/[3+2] Cycloadditions: Synthesis of Highly Substituted Cyclopenta[c]furans (pages 2838–2841)

      Hongyin Gao, Xingxing Wu and Prof. Dr. Junliang Zhang

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201003363

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      The domino effect: A novel, cationic, gold(I)-catalyzed [3+2], tandem bicyclization, which provides rapid, efficient, and diastereoselective access to highly substituted cyclopenta[c]furans from simple, readily available 2-(1-alkynyl)-2-alken-1-ones and 3-styrylindoles under mild conditions, is described (see scheme).

    6. Asymmetric Organocatalysis

      Organocatalytic Michael–Alkylation Cascade: The Enantioselective Nitrocyclopropanation of Oxindoles (pages 2842–2845)

      Fabio Pesciaioli, Prof. Dr. Paolo Righi, Prof. Dr. Andrea Mazzanti, Prof. Giuseppe Bartoli and Dr. Giorgio Bencivenni

      Version of Record online: 9 FEB 2011 | DOI: 10.1002/chem.201003423

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      The spiro saga goes on! The title reaction sequence provides the first enantioselective synthesis of spiro nitrocyclopropyl oxindoles. The method provides easy access to these new, biologically inspired compounds from readily available starting materials (see scheme).

    7. Chiral Lewis Base Catalyzed Highly Enantioselective Reduction of N-Alkyl β-Enamino Esters with Trichlorosilane and Water (pages 2846–2848)

      Xinjun Wu, Yang Li, Chao Wang, Li Zhou, Prof. Dr. Xiaoxia Lu and Prof. Dr. Jian Sun

      Version of Record online: 10 FEB 2011 | DOI: 10.1002/chem.201003105

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      First, test the water! In the presence of a chiral Lewis base catalyst 2, the supposedly moisture-unfriendly reduction system with trichlorosilane was found to be highly efficient and enantioselective when using water as an additive. For the first time, this method enables the reduction of a broad range of N-alkyl β-enamino esters 1 to give N-alkyl β-amino esters 3 in good to high yields and with excellent enantioselectivities (see scheme).

  7. Full Papers

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

      A Click Fluorophore Sensor that Can Distinguish CuII and HgII via Selective Anion-Induced Demetallation (pages 2850–2858)

      Yu Heng Lau, Dr. Jason R. Price, Dr. Matthew H. Todd and Dr. Peter J. Rutledge

      Version of Record online: 8 FEB 2011 | DOI: 10.1002/chem.201002477

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      Strong reaction: Azamacrocyclic complexes with a pendant triazole ligand are easily assembled by using “click” chemistry. By reversing the azide and alkyne coupling partners, a novel triazole scorpion is formed. This gives a fluorescent sensor that responds strongly to CuII and HgII in neutral aqueous solution.

    2. Hydrogen-Bond Catalysis

      Stereoelectronic Requirements for Optimal Hydrogen-Bond-Catalyzed Enolization (pages 2859–2866)

      Dr. Imre Pápai, Dr. Andrea Hamza, Prof. Petri M. Pihko and Prof. Rik K. Wierenga

      Version of Record online: 9 FEB 2011 | DOI: 10.1002/chem.201002943

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      Computational results reveal that the preferred in-plane lone-pair directionality of hydrogen-bond donors (HBDs) of hydrogen-bonded carbonyl groups is reduced upon enolization (see figure). If the HBDs can be forced to interact with the carbonyl perpendicular (PP) to the C[DOUBLE BOND]O plane this results in more favorable kinetics and thermodynamics. This PP arrangement is found in enolizing enzymes, and could be used in synthetic enolizing catalysts.

    3. DNA Recognition

      Genotyping by Alkaline Dehybridization Using Graphically Encoded Particles (pages 2867–2873)

      Dr. Huaibin Zhang, Adam J. DeConinck, Dr. Scott C. Slimmer, Prof. Patrick S. Doyle, Prof. Jennifer A. Lewis and Prof. Ralph G. Nuzzo

      Version of Record online: 8 FEB 2011 | DOI: 10.1002/chem.201002848

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      pH-based genotyping: A nonenzymatic, isothermal, and potentially high-throughput genotyping method is based on the kinetic differences exhibited in the dehybridization of perfectly matched and single-base mismatched DNA duplexes (see picture) in an alkaline solution using fluorescence microscopy. A multifunctional encoded hydrogel particle array (fabricated by stop-flow lithography) is used to achieve fast kinetics and high versatility.

    4. Zeolites

      Coke Formation during the Methanol-to-Olefin Conversion: In Situ Microspectroscopy on Individual H-ZSM-5 Crystals with Different Brønsted Acidity (pages 2874–2884)

      Davide Mores, Dr. Jan Kornatowski , Prof. Dr. Unni Olsbye and Prof. Dr. Ir. Bert M. Weckhuysen

      Version of Record online: 8 FEB 2011 | DOI: 10.1002/chem.201002624

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      Coke species on the move! UV/Vis and confocal fluorescence microscopy demonstrated that the formation of distinct coke species during the methanol-to-olefin conversion on individual H-ZSM-5 zeolite crystals (schematically depicted) differed with Brønsted acid site density and applied reaction conditions.

    5. Synthetic Methods

      γ- and δ-Lactams through Palladium-Catalyzed Intramolecular Allylic Alkylation: Enantioselective Synthesis, NMR Investigation, and DFT Rationalization (pages 2885–2896)

      Dr. Xavier Bantreil, Dr. Guillaume Prestat, Dr. Aitor Moreno, Dr. David Madec, Dr. Peter Fristrup, Prof. Per-Ola Norrby, Prof. Paul S. Pregosin and Prof. Giovanni Poli

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201001300

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      A transient existence: The Pd-catalyzed intramolecular allylic alkylation of unsaturated amides to give γ- and δ-lactams in the presence of (R)-3,5-tBu-MeOBIPHEP takes place in up to 94:6 enantiomeric ratio (e.r.; see scheme). The energies of the diastereomeric transition states are in good agreement with the experimentally observed enantiomeric ratios. The preparation, isolation, and cyclization of the η3-allylpalladium complex expected to transiently form in the catalytic experiments were also successfully carried out.

    6. Imaging Mass Spectrometry

      Multivariate Statistical Identification of Human Bladder Carcinomas Using Ambient Ionization Imaging Mass Spectrometry (pages 2897–2902)

      Allison L. Dill, Livia S. Eberlin, Dr. Anthony B. Costa, Dr. Cheng Zheng, Dr. Demian R. Ifa, Dr. Liang Cheng, Dr. Timothy A. Masterson, Dr. Michael O. Koch, Prof. Olga Vitek and Prof. R. Graham Cooks

      Version of Record online: 31 JAN 2011 | DOI: 10.1002/chem.201001692

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      Light up the dark: Molecular pathology diagnosis by imaging mass spectrometry that uses desorption electrospray ionization is presented (see picture). The method allows the distinction between transitional cell carcinoma of the urinary bladder and adjacent normal tissues, based on the glycerophospholipid profiles, and a classification through multivariate statistical analysis.

    7. DNA Sequencing

      You have full text access to this OnlineOpen article
      Fluoride-Cleavable, Fluorescently Labelled Reversible Terminators: Synthesis and Use in Primer Extension (pages 2903–2915)

      Diana C. Knapp, Dr. Saulius Serva, Dr. Jennifer D'Onofrio, Dr. Angelika Keller, Dr. Arvydas Lubys, Prof. Dr. Ants Kurg, Prof. Dr. Maido Remm and Prof. Dr. Joachim W. Engels

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201001952

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      Bright new things: A new set of fluorescently labelled reversible terminators has been synthesised (see picture). A polymerase able to incorporate these compounds was found, and the complete system of terminator–polymerase was successfully used in a cyclic reversible terminating approach on CodeLink slides spotted with oligonucleotide probes.

    8. Asymmetric Catalysis

      Molybdenum-Catalyzed Asymmetric Allylic Alkylation of 3-Alkyloxindoles: Reaction Development and Applications (pages 2916–2922)

      Prof. Barry M. Trost and Dr. Yong Zhang

      Version of Record online: 2 FEB 2011 | DOI: 10.1002/chem.201002569

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      Complementary reaction: We report a full account of our work towards the development of Mo-catalyzed asymmetric allylic alkylation reactions with 3-alkyloxindoles as nucleophiles. The reaction is complementary to the Pd-catalyzed reaction with regard to the scope of oxindole nucleophiles. A number of 3-alkyloxindoles were alkylated successfully under mild conditions to give products such as ent-(−)-debromoflustramine B, and the indolinoquinoline rings of communesin B with excellent yields and good-to-excellent enantioselectivities.

    9. Nanocrystal Morphology

      Influence of the Counterion on the Synthesis of ZnO Mesocrystals under Solvothermal Conditions (pages 2923–2930)

      Dr. Monica Distaso, Prof. Robin N. Klupp Taylor, Dr. Nicola Taccardi, Prof. Peter Wasserscheid and Prof. Wolfgang Peukert

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201002235

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      Not “just”the anion! The choice of the anion of the starting salt precursor is a critical point for the synthesis of ZnO mesocrystals under solvothermal conditions. In the present paper two anions, nitrate and acetate, namely a non-coordinating and a chelating anion, are considered as starting salts for ZnO mesocrystals. Their different behavior in the same experimental conditions is highlighted (see picture).

    10. Oxidation

      Haloperoxidase Activity of Oxovanadium(V) Thiobisphenolates (pages 2931–2938)

      C. Gunnar Werncke, Prof. Dr. Christian Limberg, Christina Knispel, Ramona Metzinger and Dr. Beatrice Braun

      Version of Record online: 2 FEB 2011 | DOI: 10.1002/chem.201002890

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      Oxygen overload: Oxovanadium peroxides (see figure) are formed on addition of H2O2 to thiobisphenolato dioxovanadates. They rapidly oxidize the internal thioether function, whereas the sulfoxidation of external substrates requires further activation by protons or alkyl cations like in haloperoxidases.

    11. Dyes/Pigments

      Synthesis and Characterization of Near-Infrared Absorbing Benzannulated Aza-BODIPY Dyes (pages 2939–2947)

      Roland Gresser, Markus Hummert, Horst Hartmann, Karl Leo and Moritz Riede

      Version of Record online: 2 FEB 2011 | DOI: 10.1002/chem.201002941

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      Beneficial benzannulation: A series of benzannulated aza-BODIPYs derived from diisoindol-azamethines have been prepared and characterized by UV/Vis spectroscopy and cyclic voltammetry. DFT calculations complete the experimental studies and confirm a proposed reaction mechanism.

    12. Cross-Coupling Reactions

      Pd- and Ni-Catalyzed Cross-Coupling Reactions of Functionalized Organozinc Reagents with Unsaturated Thioethers (pages 2948–2956)

      Laurin Melzig, Albrecht Metzger and Prof. Dr. Paul Knochel

      Version of Record online: 30 JAN 2011 | DOI: 10.1002/chem.201002850

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      Versatile cross-coupling reactions: Various unsaturated thioethers have been subjected to cross-coupling reactions with functionalized zinc reagents in the presence of a transition-metal catalyst (see scheme). Three different catalytic systems based on Pd(OAc)2 or [Ni(acac)2] and the ligands S-Phos or DPE-Phos gave the best results.

    13. Conjugation

      A Fully Conjugated TTF–π–TCAQ System: Synthesis, Structure, and Electronic Properties (pages 2957–2964)

      Dr. José Santos, Dr. Beatriz M. Illescas, Prof. Dr. Nazario Martín, Dr. Javier Adrio, Prof. Dr. Juan C. Carretero, Dr. Rafael Viruela, Prof. Dr. Enrique Ortí, Dr. Fabian Spänig and Prof. Dr. Dirk M. Guldi

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201002674

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      Building bridges: A new molecule that involves tetrathiafulvalene (TTF)- and tetracyano-p-quinodimethane (TCNQ)-type moieties connected through a conjugated bridge has been prepared (see image). The synthesis has been carried out from an exTTF building block containing a sulfone group, the versatility of which paves the way to a variety of Julia–Kocienski olefination reactions.

    14. Cross-Coupling

      Well-Defined Air-Stable Palladium HASPO Complexes for Efficient Kumada–Corriu Cross-Couplings of (Hetero)Aryl or Alkenyl Tosylates (pages 2965–2971)

      Prof. Dr. Lutz Ackermann, Dr. Anant R. Kapdi, Dipl.-Chem. Sabine Fenner, Dipl.-Chem. Christoph Kornhaaß and Dr. Carola Schulzke

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201002386

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      HASPO: Novel palladium complexes of heteroatom-substituted secondary phosphine oxides (HASPO) were synthesized, and served as highly efficient catalysts for Kumada–Corriu cross-coupling reactions of aryl, alkenyl, and heteroaryl tosylates at low catalyst loadings with ample scope.

    15. Synthetic Methods

      Ring-Rearrangement Metathesis of Nitroso Diels–Alder Cycloadducts (pages 2972–2980)

      Dr. Guillaume Vincent  and Prof. Cyrille Kouklovsky

      Version of Record online: 8 FEB 2011 | DOI: 10.1002/chem.201002558

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      From one bicycle to another: Nitroso Diels–Alder (NDA) bicycloadducts have been converted into valuable fused bicycles that contain N[BOND]O bonds by using Grubbs or Hoveyda ruthenium carbene catalysts, through a ring-rearrangement metathesis (RRM) process (see scheme). These scaffolds are of synthetic relevance for the generation of molecular diversity and for the total synthesis of alkaloids.

    16. Antibiotics

      Novel and Efficient Copper-Catalysed Synthesis of Nitrogen-Linked Medium-Ring Biaryls (pages 2981–2986)

      Dr. Jayne L. Kenwright, Dr. Warren R. J. D. Galloway, Dr. David T. Blackwell, Dr. Albert Isidro-Llobet, James Hodgkinson, Dr. Lars Wortmann, Dr. Steven D. Bowden, Dr. Martin Welch and Dr. David R. Spring

      Version of Record online: 2 FEB 2011 | DOI: 10.1002/chem.201002093

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      A new strategy for the synthesis of rare nitrogen-linked seven-, eight- and nine-membered biaryl ring systems is described based on the generation of a highly active intramolecular form of copper (see scheme). The auxiliary atom allows internal chelation to form the active copper species and its geometry may facilitate ring closure. This technically simple process proceeds under relatively mild conditions to produce a broad range of otherwise difficult to synthesise products.

    17. Macrocycles

      Synthesis and Isomerization Studies of Cyclotrisazobiphenyl (pages 2987–2995)

      Raphael Reuter and Dr. Hermann A. Wegner

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201002671

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      Switching in 3D: The efficient preparation of switchable conjugated macrocycles containing three azobenzene units and their photochromic properties are reported. The final macrocyclization step was conducted in up to 80% yield and relied on a metal template effect. The macrocycles exhibit four different isomers on irradiation. By choosing the appropriate conditions (solvent, wavelength) each of the isomers can be enhanced in the photostationary state.

    18. Carbolithiation

      Mechanistic Insight into Stereoselective Carbolithiation (pages 2996–3004)

      Dr. Viktoria H. Gessner, Stephan G. Koller, Prof. Dr. Carsten Strohmann, Dr. Anne-Marie Hogan and Prof. Dr. Donal F. O'Shea

      Version of Record online: 3 FEB 2011 | DOI: 10.1002/chem.201000814

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      Asymmetric carbolithiation of β-methylstyrene (X=H) and an amino-functionalised derivative (X=NHBn) was investigated mechanistically on the basis of X-ray structure analyses (see picture) and computational studies. Competing steric interactions in the transition states of the carbolithiation of β-methylstyrene show an influence of the alkyl lithium reagent on stereoselectivity, while the rather rigid structures of the amino-functionalised system point to a crucial role of all substituents.

    19. Multicomponent Reactions

      Gold-Nanoparticle-Catalyzed Synthesis of Propargylamines: The Traditional A3-Multicomponent Reaction Performed as a Two-Step Flow Process (pages 3005–3010)

      Lahbib Abahmane, J. Michael Köhler and Dr. G. Alexander Groß

      Version of Record online: 31 JAN 2011 | DOI: 10.1002/chem.201002043

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      Clay and gold: Two heterogeneous catalysts have been used sequentially to perform the alkyne, aldehyde, amine A3-multicomponent reaction under flow-chemistry conditions (see picture). Montmorillonite K-10 and gold nanoparticles impregnated on alumina (Au-NP@Al2O3) have been used in micro packed-bed capillary reactors at different temperatures. An increased reaction performance was achieved in terms of shortened reaction time. Propargylamines were obtained in good yields, even when acyclic amine and aliphatic aldehyde building blocks were used.

    20. Catalytic Dehydrocoupling

      [Ir(PCy3)2(H)2(H2B[BOND]NMe2)]+ as a Latent Source of Aminoborane: Probing the Role of Metal in the Dehydrocoupling of H3B⋅NMe2H and Retrodimerisation of [H2BNMe2]2 (pages 3011–3020)

      Charlotte J. Stevens, Romaeo Dallanegra, Dr. Adrian B. Chaplin, Prof. Andrew S. Weller, Prof. Stuart A. Macgregor, Bryan Ward, Dr. David McKay, Dr. Gilles Alcaraz and Prof. Sylviane Sabo-Etienne

      Version of Record online: 14 FEB 2011 | DOI: 10.1002/chem.201002517

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      Metal-catalysed dehydrocoupling: {Ir(PCy3)2(H)2}+ has been used to study the chemistry of the aminoborane H2B[BOND]NMe2, a central component in the dehydrocoupling of H3B⋅NMe2H. A mechanism that involves the metal in both dehydrogenation and oligomerisation, in addition to competitive off-metal dimerisation is suggested. The interaction between metal centre and H2B[BOND]NMe2 has also been used to drive the retrodimerisation of [H2BNMe2]2.

    21. Reaction Mechanisms

      Kinetic and Theoretical Studies on Alkaline Ethanolysis of 4-Nitrophenyl Salicylate: Effect of Alkali Metal Ions on Reactivity and Mechanism (pages 3021–3027)

      Prof. Ik-Hwan Um, Jin-A Seo and Prof. Masaaki Mishima

      Version of Record online: 2 FEB 2011 | DOI: 10.1002/chem.201002692

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      Choose the right path: The reaction of 1 with EtOM is strongly inhibited by the formation of stable complex 2, and proceeds unimolecularly via ketene 3 as the reactive intermediate and also through a bimolecular reaction of complex 2 with dissociated EtO.

    22. Magnetic Properties

      One-Dimensional End-To-End Azide-Bridged MnIII Complexes Incorporating Alkali Metal Ions: Slow Magnetic Relaxations and Metamagnetism (pages 3028–3034)

      Jung Hee Yoon, Jin Wuk Lee, Dae Won Ryu, Sung Won Yoon, Prof. Byoung Jin Suh, Dr. Hyoung Chan Kim and Prof. Chang Seop Hong

      Version of Record online: 31 JAN 2011 | DOI: 10.1002/chem.201002269

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      Take it slow: Three azide-bridged MnIII chains of alkali metal ions (Na+, K+, Rb+) and perchlorate anions were systematically synthesized (see figure). The magnetic properties varied from a two-step phase transition to metamagnetic transitions. Spin canting plays a central role in generating slow magnetic relaxations. Despite long-range antiferromagnetic order at TN, slow magnetic relaxation is observed in the K+ system.

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    4. Graphical Abstract
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    6. Concept
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      Preview: Chem. Eur. J. 11/2011 (page 3035)

      Version of Record online: 22 FEB 2011 | DOI: 10.1002/chem.201190048

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