Chemistry - A European Journal

Cover image for Vol. 17 Issue 23

May 27, 2011

Volume 17, Issue 23

Pages 6277–6563

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Concept
    8. Communications
    9. Full Papers
    10. Preview
    1. Cover Picture: Hemoglobin as a Nitrite Anhydrase: Modeling Methemoglobin-Mediated N2O3 Formation (Chem. Eur. J. 23/2011) (page 6277)

      Dr. Kathrin H. Hopmann, Dr. Bruno Cardey, Prof. Mark T. Gladwin, Prof. Daniel B. Kim-Shapiro and Prof. Abhik Ghosh

      Article first published online: 20 MAY 2011 | DOI: 10.1002/chem.201190114

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      The cover depicts the role of nitrite in hypoxic vasodilation. A key conundrum involves how nitrite-derived NO, generated within the red blood cells, reaches the endothelium while eluding recapture by deoxyhemoglobin. Quantum chemical studies lend credence to a recent suggestion that N2O3 (generated via TS1 or TS2) may be the actual NO-transporting vehicle. For more details see the Full Paper by A. Ghosh et al. on page 6348 ff.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Concept
    8. Communications
    9. Full Papers
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    1. Inside Cover: Chemical and Thermal Stability of Isotypic Metal–Organic Frameworks: Effect of Metal Ions (Chem. Eur. J. 23/2011) (page 6278)

      In Joong Kang, Nazmul Abedin Khan, Enamul Haque and Prof. Dr. Sung Hwa Jhung

      Article first published online: 20 MAY 2011 | DOI: 10.1002/chem.201190115

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      The stability of MOFs… … (metal–organic frameworks) has been compared to understand relative chemical and thermal stabilities of isotypic porous MOFs (metal–benzenedicarboxylates; M-BDCs). The chemical stability of MOFs depends on the inertness of central metal ions. On the other hand, the bond strength of common metal oxides determines the thermal stability of MOFs. For more details, see the Full Paper by S. H. Jhung et al. on page 6437 ff.

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Concept
    8. Communications
    9. Full Papers
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    1. Graphical Abstract: Chem. Eur. J. 23/2011 (pages 6281–6289)

      Article first published online: 20 MAY 2011 | DOI: 10.1002/chem.201190116

  4. Corrigendum

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Concept
    8. Communications
    9. Full Papers
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    1. You have free access to this content
      Corrigendum: Copper-Catalyzed C[BOND]P Coupling through Decarboxylation (page 6289)

      Jie Hu, Ning Zhao, Bin Yang, Ge Wang, Li-Na Guo, Yong-Min Liang and Shang-Dong Yang

      Article first published online: 20 MAY 2011 | DOI: 10.1002/chem.201190117

      This article corrects:

      Copper-Catalyzed C–P Coupling through Decarboxylation

      Vol. 17, Issue 20, 5516–5521, Article first published online: 14 APR 2011

  5. News

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

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

      Drug-Delivery Strategies by Using Template-Synthesized Nanotubes (pages 6296–6302)

      Jillian L. Perry, Charles R. Martin and Jon D. Stewart

      Article first published online: 11 MAY 2011 | DOI: 10.1002/chem.201002835

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      Special order delivery! Template synthesis strategies provide excellent control over both the internal and external dimensions of nanotubes. Because these methods also allow internal and external surfaces to display disparate functional groups, template-synthesized nanotubes are very attractive starting points for drug-delivery vehicles (see graphic). Several key advances have recently been made that bring this goal closer to reality and are discussed in this Concept article.

  7. Communications

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

      A Temperature-Guided Diastereoselectivity Switch During the Desymmetrization of meso-7-Azabicyclo[2.2.1]heptadiene: New Strategy towards the Synthesis of Aminocyclitols (pages 6304–6308)

      Dr. Ganesh Pandey and Salla Rajender

      Article first published online: 26 APR 2011 | DOI: 10.1002/chem.201100418

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      Strike while the iron is hot: A temperature-guided diastereoselectivity switch has been observed in the desymmetrization of meso-7-azabicyclic alkadiene. Both enantiomeric forms of this bicyclic structural framework are formed by using either of the enantiomers of hydrobenzoin (see scheme; Boc=tert-butyloxycarbonyl).

    2. Organocatalysis

      A Multicatalyst System for the One-Pot Desymmetrization/Oxidation of meso-1,2-Alkane Diols (pages 6309–6314)

      Dr. Christian E. Müller, Dr. Radim Hrdina, M. Sc. Raffael C. Wende and Prof. Dr. Peter R. Schreiner

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201100498

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      Two is better than one: We demonstrate the viability of an organocatalytic reaction sequence along a short peptide backbone that carries two independent catalytic functionalities, which allow the rapid, one-pot acylative desymmetrization and oxidation of meso-alkane-1,2-diols to the corresponding acetylated acetoins with good yields and enantioselectivities (see scheme).

    3. C[BOND]H Activation

      On the Importance of an Acid Additive in the Synthesis of Pyrido[1,2-a]benzimidazoles by Direct Copper-Catalyzed Amination (pages 6315–6320)

      Dr. Kye-Simeon Masters, Tom R. M. Rauws, Dr. Ashok K. Yadav, Prof. Dr. Wouter A. Herrebout, Prof. Dr. Benjamin Van der Veken and Prof. Dr. Bert U. W. Maes

      Article first published online: 20 APR 2011 | DOI: 10.1002/chem.201100574

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      Not just an acid! An expedient and highly modular synthesis of 6-, 7-, and 8-substituted pyrido[1,2-a]benzimidazoles (4) has been developed by a direct intramolecular C[BOND]H amination of N-phenylpyridin-2-amines (3). Efficient C[BOND]H amination of 3 could only be achieved in the presence of catalytic copper and an acid additive. The type of acid (pKa) proved to be crucial for the catalysis. C[BOND]Cl aminations in N-(2-chloroaryl)pyridin-2-amines allow access to 9-substituted pyrido[1,2-a]benzimidazoles.

    4. Oxidative Arylation

      Copper-Catalyzed Oxidative Arylation of Heteroarenes under Mild Conditions Using Dioxygen as the Sole Oxidant (pages 6321–6325)

      Fanzhi Yang, Prof. Zhaoqing Xu, Zhe Wang, Prof. Zhengkun Yu and Prof. Rui Wang

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201100136

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      Dioxy-gently does it! A new copper-catalyzed oxidative cross-coupling reaction between heteroarenes and arylboronic esters has been developed. Uniformly high yields are obtained by using dioxygen as the sole oxidant under mild conditions (see scheme).

    5. Cyclization Reactions

      Nickel-Catalyzed Cyclizations of Enoates and Chiral Allenes: An Approach to Domoic Acid (pages 6326–6329)

      Dr. Ahmad S. ElDouhaibi, Dr. Refaie M. Kassab, Dr. Minsoo Song and Prof. Dr. John Montgomery

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201100444

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      Come on allene, taloo-rye-aye! The first examples of nickel-catalyzed enoate/chiral allene cyclization reactions are reported. In the coupling process employing dimethylzinc, densely functionalized pyrrolidines are obtained with stereoselective installation of the C3 and C4 chiral centers and the diene functionality at C4. The process provides rapid access to an advanced intermediate towards the synthesis of domoic acid (see graphic).

    6. Optoelectronic Materials

      Pure Organic Redox Couple for Quantum-Dot-Sensitized Solar Cells (pages 6330–6333)

      Dr. Zhijun Ning, Dr. Haining Tian, Chunze Yuan, Dr. Ying Fu, Prof. Licheng Sun and Prof. Hans Ågren

      Article first published online: 21 APR 2011 | DOI: 10.1002/chem.201003527

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      A pure organic electrolyte McMT/BMT was introduced for quantum-dot-sensitized solar cells for the first time. The overall conversion efficiency of the cell is significantly improved by the utilization of the organic electrolyte (see scheme).

    7. Asymmetric Synthesis

      Enantiocontrolled Synthesis of β-Branched α-Amino Acids by Using CuI-Catalyzed 1,4-Addition of Glycine Imines to β-Substituted gem-Diactivated Olefins (pages 6334–6337)

      Jorge Hernández-Toribio, Dr. Ramón Gómez Arrayás and Prof. Dr. Juan C. Carretero

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201100374

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      Branching out! The catalytic asymmetric conjugate addition of glycinate Schiff bases to β-substituted gem-diactivated Michael acceptors under proton transfer conditions gives a variety of β-branched α-amino acids (see scheme; Dpm=diphenylmethylene, EWG=electron-withdrawing group) with excellent levels of diastereo- (typically syn/anti >90:10) and enantiocontrol (90–99 % ee).

  8. Full Papers

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

      On the Configuration of Five-Membered Rings: A Spin–Spin Coupling Constant Approach (pages 6338–6347)

      Dr. José G. Napolitano, Dr. José A. Gavín, Dr. Celina García, Prof. Dr. Manuel Norte, Dr. José J. Fernández and Dr. Antonio Hernández Daranas

      Article first published online: 5 MAY 2011 | DOI: 10.1002/chem.201100412

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      A simple and efficient approach for stereochemical analysis of five-membered rings based on the measurement of NMR coupling constants is presented (see graphic). The relative configuration of these rings can be determined without the need for further conformational considerations.

    2. Heme Proteins

      Hemoglobin as a Nitrite Anhydrase: Modeling Methemoglobin-Mediated N2O3 Formation (pages 6348–6358)

      Dr. Kathrin H. Hopmann, Dr. Bruno Cardey, Prof. Mark T. Gladwin, Prof. Daniel B. Kim-Shapiro and Prof. Abhik Ghosh

      Article first published online: 17 MAY 2011 | DOI: 10.1002/chem.201003578

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      Nitrite as signaling molecule: An unresolved aspect of nitric oxide physiology involves processes that prevent capture of NO by heme species. A possible scenario involves transformation of NO into an intermediate that is less likely to be captured, allowing it to diffuse to relevant target sites. A key candidate for such an intermediate is the N2O3 molecule. Evidence is presented in favor of hemoglobin's role as a nitrite anhydrase and of N2O3's viability as a NO vehicle (see figure).

    3. Photochromism

      Synthesis and Characterization of a Symmetric Bis(7-hydroxyflavylium) Containing a Methyl Viologen Bridge (pages 6359–6368)

      Ana M. Diniz, Dr. Carlos Pinheiro, Dr. Vesselin Petrov, Dr. A. Jorge Parola and Prof. Fernando Pina

      Article first published online: 19 APR 2011 | DOI: 10.1002/chem.201003726

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      Bridged bis(flavylium): A bis(7-hydroxyflavylium) with a viologen bridge was synthesized (see scheme), and the thermodynamics and kinetics of the network of chemical reactions was studied by stopped flow and flash photolysis. The system is not completely stochastic, the isomerization of one branch having a small influence on the isomerization of the other. Reduction of the viologen bridge in the bis(trans-chalcone) leads to the respective radical cation.

    4. Molecular Recognition

      Molecular Recognition at the Active Site of Catechol-O-methyltransferase (COMT): Adenine Replacements in Bisubstrate Inhibitors (pages 6369–6381)

      Dr. Manuel Ellermann, Dr. Ralph Paulini, Dr. Roland Jakob-Roetne, Dr. Christian Lerner, Dr. Edilio Borroni, Doris Roth, Dr. Andreas Ehler, Dr. W. Bernd Schweizer, Dr. Daniel Schlatter, Dr. Markus G. Rudolph and Prof. Dr. François Diederich

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201003648

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      Replacements for adenine: The molecular recognition properties of the adenine binding site of catechol-O-methyltransferase (COMT) were investigated. A series of bisubstrate inhibitors with novel substitutes for adenine were synthesized, resulting in IC50 values down to 6 nM. The most important protein–ligand interactions were identified with the help of six high-resolution X-ray cocrystal structures of the inhibitors bound to COMT in the presence of Mg2+. The role of water molecules in adjusting and mediating protein–ligand interactions in the binding pocket is highlighted.

    5. Molecular Tellurium

      Neutral Tellurium Rings in the Coordination Polymers [Ru(Te9)](InCl4)2, [Ru(Te8)]Cl2, and [Rh(Te6)]Cl3 (pages 6382–6388)

      Dipl.-Chem. Anja Günther, Dr. Anna Isaeva, Dr. Alexey I. Baranov and Prof. Dr. Michael Ruck

      Article first published online: 21 APR 2011 | DOI: 10.1002/chem.201003558

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      Tellurium in a new shape: Rings of nine, eight, and six tellurium atoms are stabilized by the coordination of ruthenium(II) or rhodium(III) atoms (see picture). The tellurium atoms act as two-electron donors to the transition metals.

    6. Dendrimers

      Hierarchical Self-Assembly of Amphiphilic Peptide Dendrons: Evolution of Diverse Chiral Nanostructures Through Hydrogel Formation Over a Wide pH Range (pages 6389–6395)

      Pengfei Duan, Long Qin, Xuefeng Zhu and Prof. Dr. Minghua Liu

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201003049

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      Supramolecular hydrogels: An amphiphilic dendron containing three dendrite L-glutamic acid units and a long alkyl chain was found to form hydrogels over a wide pH range from 2 to 13. Accompanying the pH change, the compounds self-assembled into various chiral structures: from helical nanotube, helical nanotube with a string of beads, and coiled superhelix to dendrite nanostructures, such as pine and feather (see figure).

    7. Glycopeptides

      Towards a Fully Synthetic MUC1-Based Anticancer Vaccine: Efficient Conjugation of Glycopeptides with Mono-, Di-, and Tetravalent Lipopeptides Using Click Chemistry (pages 6396–6406)

      Hui Cai, Zhi-Hua Huang, Lei Shi, Prof. Dr. Yu-Fen Zhao, Prof. Dr. Horst Kunz and Prof. Dr. Yan-Mei Li

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201100217

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      Click to conjugate! The tumor-associated mucin MUC1 is heavily glycosylated and, therefore, an attractive target for cancer immunotherapy. However, MUC1 glycopeptides exhibit low immunogenicity. Therefore, covalent linking to the toll-like receptor 2 (TLR 2) lipopeptide ligand Pam3CSK5, which acts as an immunostimulant, was performed by using click chemistry to give mono-, di-, and tetravalent glycopeptide vaccines (see graphic).

    8. Coordination Compounds

      Bioconjugates of Enantiomerically Pure Organopalladium Compounds by Metal-Assisted Positional Selective Transesterifications at Palladium Enolates (pages 6407–6414)

      Prof. Dr. A. Stephen K. Hashmi, Dipl.-Chem. Dominic Riedel, Dr. Marc A. Grundl, Dr. Bärbel C. Wittel, Dipl.-Chem. Andreas Föll, Dr. Jana Lubkoll, Dr. Telisha Traut, Dr. Raymond Hewer, Dr. Frank Rominger, Dr. Wolfgang Frey and Dr. Jan W. Bats

      Article first published online: 21 APR 2011 | DOI: 10.1002/chem.201003308

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      Getting connected: Selective modification of the ester groups proximal to the metal center allows the synthesis of conjugates of chiral palladacycles with biomolecules and fluorescence dyes (see figure).

    9. Sensitizers

      Phenoxazine Dyes for Dye-Sensitized Solar Cells: Relationship Between Molecular Structure and Electron Lifetime (pages 6415–6424)

      Karl Martin Karlsson, Dr. Xiao Jiang, Susanna K Eriksson, Erik Gabrielsson, Dr. Håkan Rensmo, Prof. Anders Hagfeldt and Prof. Licheng Sun

      Article first published online: 20 APR 2011 | DOI: 10.1002/chem.201003730

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      Make a donation: The structural modification of phenoxazine-based sensitizers has a large influence on the electron lifetime, which in turn affects the overall performance of solar cells. Of the five dyes synthesized (see scheme), the best dye shows a solar energy-to-electricity conversion efficiency of 7.4 %, together with a high open-circuit photovoltage of 800 mV.

    10. Hydrogen Generation

      Photocatalytic Hydrogen Generation from Water with Iron Carbonyl Phosphine Complexes: Improved Water Reduction Catalysts and Mechanistic Insights (pages 6425–6436)

      Felix Gärtner, Albert Boddien, Enrico Barsch, Dr. Koichi Fumino, Dr. Sebastian Losse, Dr. Henrik Junge, Dr. Dirk Hollmann, Prof. Dr. Angelika Brückner, Prof. Dr. Ralf Ludwig and Prof. Dr. Matthias Beller

      Article first published online: 19 APR 2011 | DOI: 10.1002/chem.201003564

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      Reduced circumstances: Turnover numbers of up to 1600 and an incident photon-to-hydrogen efficiency of 13.4 % were achieved with an iron-based water-reduction catalyst combined with an iridium photosensitizer (see picture). Mechanistic investigations were carried out by NMR and in situ FTIR spectroscopy and DFT calculations. [HFe3(CO)11] was identified as the active iron species during photocatalytic hydrogen evolution from water.

    11. Metal–Organic Frameworks

      Chemical and Thermal Stability of Isotypic Metal–Organic Frameworks: Effect of Metal Ions (pages 6437–6442)

      In Joong Kang, Nazmul Abedin Khan, Enamul Haque and Prof. Dr. Sung Hwa Jhung

      Article first published online: 5 MAY 2011 | DOI: 10.1002/chem.201100316

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      Stability of MOFs: The chemical and thermal stabilities of isotypic MOFs (metal–organic frameworks) were evaluated in a wide range of conditions to understand the effect of central metal ions on the stabilities. The chemical stabilities in acids, bases and water increase with increasing inertness of the central metal ions. On the other hand, the thermal stability depends on the strength of the metal–oxygen bond of common oxides.

    12. Molecular Motion

      Porphyrin-Based Switchable Molecular Turnstiles (pages 6443–6452)

      Dr. Aurélie Guenet, Dr. Ernest Graf, Nathalie Kyritsakas and Prof. Dr. Mir Wais Hosseini

      Article first published online: 20 APR 2011 | DOI: 10.1002/chem.201100057

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      Flicking the switch: Switching between open and closed states of molecular turnstiles composed of a stator (porphyrins with interaction sites at the meso positions), a hinge (SnIV located at the centre of the porphyrin) and a rotor (a handle equipped with a tridentate coordinating site) was achieved upon simultaneous binding of either a proton or PdII by both interaction sites located on the stator and the rotor (see figure).

    13. C[BOND]H Activation

      Direct Arylation of Heteroaromatic Compounds with Congested, Functionalised Aryl Bromides at Low Palladium/Triphosphane Catalyst Loading (pages 6453–6461)

      David Roy, Sophal Mom, Prof. Dr. Dominique Lucas, Dr. Hélène Cattey, Prof. Dr. Jean-Cyrille Hierso and Dr. Henri Doucet

      Article first published online: 20 APR 2011 | DOI: 10.1002/chem.201100100

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      Be direct: A new ferrocenyl triphosphane ligand associated to palladium was found to be an efficient catalyst at low loadings for the direct coupling of a variety of heteroarenes with highly congested, functionalised aryl bromides, such as 9-bromoanthracene, 1-bromo-2-methylnaphthalene or 2-bromo-3-methylbenzonitrile (see scheme).

    14. Metal–Organic Frameworks

      High-Throughput and Time-Resolved Energy-Dispersive X-Ray Diffraction (EDXRD) Study of the Formation of CAU-1-(OH)2: Microwave and Conventional Heating (pages 6462–6468)

      Tim Ahnfeldt, Jens Moellmer, Vincent Guillerm, Prof. Reiner Staudt, Dr. Christian Serre and Prof. Norbert Stock

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201003708

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      Crystal clarity: CAU-1-(OH)2 is a hydroxyl-functionalized metal–organic framework. It is stable under ambient conditions and exhibits permanent porosity and two types of cavity with effective diameters of around 1 and 0.45 nm. Its crystallization was studied by in situ energy-dispersive X-ray diffraction experiments. Two heating methods were investigated (see image).

    15. Stereoselective Synthesis

      Stereocomplementary Syntheses of 1,ω-Distannylated E,Z-Isomeric Conjugated Trienes, Tetraenes, and Pentaenes (pages 6469–6483)

      Dr. Jochen Burghart, Dr. Achim Sorg and Prof. Dr. Reinhard Brückner

      Article first published online: 21 APR 2011 | DOI: 10.1002/chem.201001629

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      EorZfor choice: Unbranched or methylated 1,ω-bis(tributyl)stannylated 1,3,5-trienes, 1,3,5,7-tetraenes, and 1,3,5,7,9-pentaenes were prepared in such a way that a tin-free disubstituted C[DOUBLE BOND]C bond was established in the final step. This gave all-E-configured polyenes by using the Ramberg–Bäcklund olefination and mono-Z-configured polyenes by using the (Sylvestre–) Julia olefination (see scheme; KHMDS=potassium hexamethyldisilazide).

    16. Cascade Reactions

      Enantioselective Intramolecular Crossed Rauhut–Currier Reactions through Cooperative Nucleophilic Activation and Hydrogen-Bonding Catalysis: Scope and Mechanistic Insight (pages 6484–6491)

      Xu-Fan Wang, Liang Peng, Jing An, Chao Li, Qing-Qing Yang, Liang-Qiu Lu, Prof. Dr. Feng-Long Gu and Prof. Dr. Wen-Jing Xiao

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201100479

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      Working together: Cooperative nucleophilic activation and hydrogen-bonding catalysis allow a highly efficient and enantioselective intramolecular crossed Rauhut–Currier (RC) reaction of nitroolefins with tethered enonates (≤98 % ee, 98 % yield; see scheme). Computational investigations indicate that the stereoselectivity of the RC reaction is determined by the intramolecular Michael addition and the rate-determining step is a retro-aza-Michael addition reaction.

    17. Fluorescence Switching

      Molecular Implementation of Sequential and Reversible Logic Through Photochromic Energy Transfer Switching (pages 6492–6500)

      Patricia Remón, Martin Hammarson, Dr. Shiming Li, Dr. Axel Kahnt, Dr. Uwe Pischel and Prof. Dr. Joakim Andréasson

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201100027

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      In order to switch: Molecular switches in the form of spiropyran (SP)–spacer–fluorophore (F) dyads (see graphic) have been used to implement sequential logic (2-input priority AND gate) and reversible logic. The dyads were designed to yield readily predictable fluorescence responses by modulation of electronic energy transfer. In this way switches that can be conveniently operated, recycled and reset through photochromic processes and acid–base chemistry were obtained.

    18. Frustrated Lewis Pairs

      On the Mechanism of Irreversible Carbon Dioxide Binding with a Frustrated Lewis Pair: Solvent-Assisted Frustration and Transition-State Entropic Encouragement (pages 6501–6507)

      Hee Jae Kwon, Hyun Woo Kim and Prof. Young Min Rhee

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201003483

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      Favorable frustration: The mechanism of irreversible carbon dioxide binding with the Mes3P:AlCl3 (Mes=2,4,6-C6H2Me3) Lewis pair is investigated. The specific solute–solvent interaction between the Lewis pair and the solvent molecule, but not the steric congestion on the Lewis pair, assists frustration in the pair formation and participates significantly in binding with CO2 (see image).

    19. Ionic Liquids

      Going Full Circle: Phase-Transition Thermodynamics of Ionic Liquids (pages 6508–6517)

      Dr. Ulrich Preiss, Prof. Dr. Sergey P. Verevkin, Prof. Dr. Thorsten Koslowski and Prof. Dr. Ingo Krossing

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201003150

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      The circle is closed: For the first time, the thermodynamic circle of phase-change enthalpies (see figure) has been closed for ionic liquids with experimental data or high-level calculations. Novel equations are developed to model single quantities easily. A full error assessment shows the high quality of our assumptions.

    20. Kinetics

      Increasing the Isomerisation Kinetics of Azo Dyes by Chemical Bonding to Liquid-Crystalline Polymers (pages 6518–6523)

      Jaume Garcia-Amorós, Prof. Dr. Heino Finkelmann and Dr. Dolores Velasco

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201003453

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      Life in the fast lane: The isomerisation process of nitro-substituted azobenzenes is accelerated up to 13 times when they are doped in low molar nematic liquid crystals. This kinetic acceleration is up to 103-times higher when the azo dye is covalently bonded to the nematic polymer backbone (see graphic, LSCE=liquid single crystal elastomer).

    21. Supported Catalysts

      Controlling the Duality of the Mechanism in Liquid-Phase Oxidation of Benzyl Alcohol Catalysed by Supported Au–Pd Nanoparticles (pages 6524–6532)

      Dr. Meenakshisundaram Sankar, Ewa Nowicka, Ramchandra Tiruvalam, Qian He, Dr. Stuart H. Taylor, Prof. Christopher J. Kiely, Prof. Donald Bethell, Prof. David W. Knight and Prof. Graham J. Hutchings

      Article first published online: 27 APR 2011 | DOI: 10.1002/chem.201003484

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      “Switch-on” or “switch-off” disproportionation: In the solvent-free oxidation of benzyl alcohol using supported gold–palladium nanoparticles, by changing the metal oxide used to support the nanoparticle catalyst from titania or niobium oxide to magnesium oxide or zinc oxide, it is possible to switch off the disproportionation reaction and thereby completely stop the toluene formation.

    22. Nucleobases

      Contiguous Metal-Mediated Base Pairs Comprising Two AgI Ions (pages 6533–6544)

      Dr. Dominik A. Megger, Dr. Célia Fonseca Guerra, Dipl.-Phys. Jan Hoffmann, Prof. Dr. Bernhard Brutschy, Prof. Dr. F. Matthias Bickelhaupt and Prof. Dr. Jens Müller

      Article first published online: 5 MAY 2011 | DOI: 10.1002/chem.201002944

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      Loading up DNA: A novel silver(I)-mediated base pair comprising 1,3-dideazaadenine and thymine can accommodate two metal ions, thereby doubling the amount of transition-metal ions that can be site-specifically attached to DNA. Nucleic acids containing contiguous base pairs of this type are still capable of reversible self-assembly (see scheme).

    23. Inhibitors

      Combining Glycomimetic and Multivalent Strategies toward Designing Potent Bacterial Lectin Inhibitors (pages 6545–6562)

      Dr. Yoann M. Chabre, Dr. Denis Giguère, Dr. Bertrand Blanchard, Jacques Rodrigue, Sylvain Rocheleau, Mathieu Neault, Subhash Rauthu, Alex Papadopoulos, Dr. Alexandre A. Arnold, Dr. Anne Imberty and Prof. René Roy

      Article first published online: 26 APR 2011 | DOI: 10.1002/chem.201003402

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      United we stand! Multivalent presentation of optimized β-C-galactopyranoside mimetics attached to various dendritic scaffolds by “click” chemistry has been achieved (see graphic). Enzyme-linked lectin assay, ITC, NMR diffusion, and computational measurements highlighted their inhibitory potencies against PA-IL lectin from the pathogenic Pseudomonas aeruginosa.

  9. Preview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Concept
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      Preview: Chem. Eur. J. 24/2011 (page 6563)

      Article first published online: 20 MAY 2011 | DOI: 10.1002/chem.201190119

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