Chemistry - A European Journal

Cover image for Vol. 19 Issue 16

April 15, 2013

Volume 19, Issue 16

Pages 4953–5197

  1. Cover Pictures

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    1. You have free access to this content
      Cover Picture: Azaphthalocyanines: Red Fluorescent Probes for Cations (Chem. Eur. J. 16/2013) (page 4953)

      Dr. Veronika Novakova, Lukáš Lochman, Ivana Zajícová, Dr. Kamil Kopecky, Dr. Miroslav Miletin, Dr. Kamil Lang, Dr. Kaplan Kirakci and Prof. Petr Zimcik

      Version of Record online: 8 APR 2013 | DOI: 10.1002/chem.201390053

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      The concept of sensing metal cations by using fluorescence changes in non-aggregating AzaPc molecules that exhibit significant intramolecular charge transfer (ICT) in the OFF state was demonstrated by binding Na+ and K+ to an aza[15]crown-5 recognition moiety. It is important to note that this concept works not only in organic solvents, but also in water after the sensor molecules are incorporated into silica nanoparticles. For more details see the Communication by V. Novakova, P. Zimcik et al. on page 5025 ff.

    2. You have free access to this content
      Back Cover: CeO2-Based Pd(Pt) Nanoparticles Grafted onto Fe3O4/Graphene: A General Self-Assembly Approach To Fabricate Highly Efficient Catalysts with Magnetic Recyclable Capability (Chem. Eur. J. 16/2013) (page 5200)

      Xiao Wang, Dapeng Liu, Shuyan Song and Prof. Dr. Hongjie Zhang

      Version of Record online: 8 APR 2013 | DOI: 10.1002/chem.201390056

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      New Pd and Pt catalysts with high catalytic efficiency have been fabricated by means of a self-assembly strategy and are composed of four components, that is, noble metal, CeO2, Fe3O4, and reduced graphene oxide (RGO). The as-obtained Pd and Pt catalysts have relatively high catalytic activity and stability in the selective hydrogenation of p-nitrophenol; they are also stable in air and exhibit a good magnetic response. For more details see the Full Paper by H. Zhang et al. on page 5169 ff.

  2. Graphical Abstract

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Concept
    7. Communications
    8. Full Papers
  3. Corrigenda

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    1. You have free access to this content
      Corrigendum: A New Class of Amphiphiles Bearing Rigid Hydrophobic Groups for Solubilization and Stabilization of Membrane Proteins (page 4964)

      Prof. Pil Seok Chae, Prof. Søren G. F. Rasmussen, Rohini R. Rana, Kamil Gotfryd, Andrew C. Kruse, Aashish Manglik, Kyung Ho Cho, Shailika Nurva, Prof. Ulrik Gether, Prof. Lan Guan, Prof. Claus J. Loland, Dr. Bernadette Byrne, Prof. Brian K. Kobilka and Prof. Samuel H. Gellman

      Version of Record online: 8 APR 2013 | DOI: 10.1002/chem.201300856

      This article corrects:
    2. You have free access to this content
      Corrigendum: Remarkable Reinforcement of a Supramolecular Gel Constructed by Heteroditopic [18]Crown-6-Based Molecular Recognition (page 4965)

      Eunyoung Noh, Dr. Sunhong Park, Sunwoo Kang, Prof. Dr. Jin Yong Lee and Prof. Dr. Jong Hwa Jung

      Version of Record online: 8 APR 2013 | DOI: 10.1002/chem.201300925

      This article corrects:
  4. News

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Concept
    7. Communications
    8. Full Papers
  5. Concept

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    1. Hydroamination

      Asymmetric Hydroamination: A Survey of the Most Recent Developments (pages 4972–4985)

      Dr. Jérôme Hannedouche and Dr. Emmanuelle Schulz

      Version of Record online: 1 MAR 2013 | DOI: 10.1002/chem.201203956

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      And the winner is…! This Concept article highlights the most recent and original progress in the field of asymmetric hydroamination of carbon–carbon double bonds (see scheme), offering nearby developments, and addressing the next challenges.

  6. Communications

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    1. Photocatalysis

      Direct Water Splitting into Hydrogen and Oxygen under Visible Light by using Modified TaON Photocatalysts with d0 Electronic Configuration (pages 4986–4991)

      Prof. Dr. Kazuhiko Maeda, Dr. Daling Lu and Prof. Dr. Kazunari Domen

      Version of Record online: 28 MAR 2013 | DOI: 10.1002/chem.201300158

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      Parting water! Direct splitting of pure water into H2 and O2 under visible light (λ>400 nm) was achieved by using a modified TaON photocatalyst with d0 electronic configuration. Modification of a less-defective TaON (ZrO2/TaON) with core/shell-structured RuOx/Cr2O3 nanoparticles and colloidal IrO2 was found to be indispensable to achieving the reaction (see figure).

    2. Synthetic Methods

      Substituent Effect of Bis(pyridines)iodonium Complexes as Iodinating Reagents: Control of the Iodocyclization/Oxidation Process (pages 4992–4996)

      Dr. Takashi Okitsu, Saki Yumitate, Kana Sato, Dr. Yasuko In and Prof. Dr. Akimori Wada

      Version of Record online: 1 MAR 2013 | DOI: 10.1002/chem.201204423

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      Halogen bond: The choice of the iodonium complex of pyridines, either IPy2PF6 or I(coll)2PF6 (Py=pyridine; coll=2,4,6-trimethylpyridine), was crucial for controlling the iodocyclization/oxidation sequence of α-propargylic glycine derivatives. This reagent-controlled system enabled switchable access to 2,3-dihydropyrroles and pyrroles (see scheme).

    3. Chiral Cooperative Catalysis

      Cooperative Iron–Brønsted Acid Catalysis: Enantioselective Hydrogenation of Quinoxalines and 2 H-1,4-Benzoxazines (pages 4997–5003)

      Steffen Fleischer, Dr. Shaolin Zhou, Svenja Werkmeister, Dr. Kathrin Junge and Prof. Dr. Matthias Beller

      Version of Record online: 5 MAR 2013 | DOI: 10.1002/chem.201204236

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      Come together! A selective Fe-catalysed enantioselective reduction of quinoxalines and benzoxazines with hydrogen is demonstrated. Key to success is the combination of a chiral Brønsted acid and a well-defined non-chiral Fe hydrogenation catalyst. This methodology constitutes an attractive and environmentally favourable alternative to well-established asymmetric hydrogenations by using precious-metal-based catalysts.

    4. Heterogeneous Catalysis

      Main-Chain Organometallic Microporous Polymers Based on Triptycene: Synthesis and Catalytic Application in the Suzuki–Miyaura Coupling Reaction (pages 5004–5008)

      Dr. Chun Zhang, Jing-Jing Wang, Ying Liu, Hui Ma, Prof. Xiang-Liang Yang and Prof. Hui-Bi Xu

      Version of Record online: 1 MAR 2013 | DOI: 10.1002/chem.201203975

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      Porous materials: Triptycene-based main-chain organometallic microporous polymers (MOMPs) bearing bis(NHC)–palladium species were synthesized and displayed excellent recoverable catalytic activity in catalyzing Suzuki–Miyaura coupling reactions (see scheme).

    5. NMR crystallography

      An NMR-Driven Crystallography Strategy to Overcome the Computability Limit of Powder Structure Determination: A Layered Aluminophosphate Case (pages 5009–5013)

      Boris Bouchevreau, Dr. Charlotte Martineau, Dr. Caroline Mellot-Draznieks, Dr. Alain Tuel, Dr. Matthew R. Suchomel, Dr. Julien Trébosc, Prof. Olivier Lafon, Prof. Jean-Paul Amoureux and Dr. Francis Taulelle

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/chem.201203767

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      Just in time: An NMR-driven structure resolution that allows structure determination from the powder diffraction data of a highly complex layered aluminophosphate, and was otherwise not possible despite the high quality of the synchrotron diffraction data, is proposed. This study shows that the strategy is general and allows reduction of the number of free parameters to search for a structure and converge under the limit of the combinatorial explosion of computing time (see figure).

    6. Synthetic Methods

      Rhodium-Catalyzed Carbocyclization and Chlorosulfonylation of 1,6-Enynes with Sulfonyl Chlorides (pages 5014–5018)

      Chen Chen, Prof. Jianhua Su and Dr. Xiaofeng Tong

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/chem.201204039

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      Linked in: A rhodium(I) catalyst system [[Rh(cod)Cl]+DPPF] enables carbocyclization and chlorosulfonylation of 1,6-enynes with sulfonyl chlorides, thus allowing the formation of three different bonds (C[BOND]Cl, C[BOND]C, and C[BOND]S) in a one-step fashion (see scheme; cod=cyclooctadiene, DPPF=1,1′-bis(diphenylphosphino)ferrocene). Sulfonyl chlorides are shown to be an efficient linker in this transformation, which complements other known element–element linkers.

    7. Carbon Nanomaterials

      Carbon Nano-Onions and Biocompatible Polymers for Flavonoid Incorporation (pages 5019–5024)

      Dr. Marta E. Plonska-Brzezinska, Diana M. Brus, Joanna Breczko and Prof. Luis Echegoyen

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/chem.201300009

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      Biocompatible onions: Different composites of carbon nano-onions (CNOs) and poly(4-vinylpyridine-co-styrene) (PVPS) or poly(ethylene glycol)/polysorbate 20 (PEG-P20) were prepared by non-covalent modification. Attachment creates the charged CNO surface for further functionalization with 3-mercaptopropionic (MPA) or 2-mercapto-4-methyl-5-thiazoleacetic acids. Such hydrophilic CNO composites were an appropriate platform for electrostatic immobilization of polyphenolic compounds, such as quercetin (Q).

    8. Crown Compounds

      Azaphthalocyanines: Red Fluorescent Probes for Cations (pages 5025–5028)

      Dr. Veronika Novakova, Lukáš Lochman, Ivana Zajícová, Dr. Kamil Kopecky, Dr. Miroslav Miletin, Dr. Kamil Lang, Dr. Kaplan Kirakci and Prof. Petr Zimcik

      Version of Record online: 19 MAR 2013 | DOI: 10.1002/chem.201300079

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      Light up a red crown: Chelation of sodium and potassium cations by aza[15]crown-5 switches on strong red fluorescence in azaphthalocyanines. This is due to an inhibition of ultrafast intramolecular charge transfer by coordination of the cations to the donor center. Sodium cations fit well into a cavity of the recognition moiety, while potassium forms supramolecular assemblies of azaphthalocyanines with 1:2 stoichiometry.

    9. Sensors

      Label-Free Colorimetric Detection of Arsenite Utilizing G-/T-Rich Oligonucleotides and Unmodified Au Nanoparticles (pages 5029–5033)

      Prof. Ru-Ping Liang, Zhong-Xia Wang, Dr. Li Zhang and Prof. Jian-Ding Qiu

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/chem.201203402

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      “Free” arsenite sensor: Based on the principle that G-/T-rich single-stranded DNA (ssDNA) and folded DNA bound to arsenite have different propensities to adsorb onto Au nanoparticles (Au NPs) in colloidal solution, a label-free colorimetric assay for arsenite sensing based on color changes associated with the aggregation of Au NPs has been designed (see scheme).

  7. Full Papers

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    1. Peptide Nucleic Acids

      A Peptide Nucleic Acid (PNA) Heteroduplex Probe Containing an Inosine–Cytosine Base Pair Discriminates a Single-Nucleotide Difference in RNA (pages 5034–5040)

      Dr. Katsuhiko Matsumoto, Dr. Eiji Nakata, Tomoki Tamura, Prof. Dr. Isao Saito, Dr. Yasunori Aizawa and Prof. Dr. Takashi Morii

      Version of Record online: 13 MAR 2013 | DOI: 10.1002/chem.201204183

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      Discrimination in the workplace: A peptide nucleic acid (PNA)-derived probe, in which PNA forms a pseudocomplementary heteroduplex with inosine-containing DNA or RNA, effectively discriminates a single-nucleotide difference in a closely related group of sequences of single-stranded DNA and/or RNA (see figure).

    2. Carbohydrates

      Hydrophobic and Hydrophilic Balance and Its Effect on Mesophase Behaviour in Hydroxyalkyl Ethers of Methyl Glucopyranoside (pages 5041–5049)

      Dr. Madan K. Singh, Rui Xu, Dr. Sylvie Moebs, Dr. Anil Kumar, Dr. Yves Queneau, Dr. Stephen J. Cowling and Prof. John W. Goodby

      Version of Record online: 20 FEB 2013 | DOI: 10.1002/chem.201202933

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      Balancing act: The thermotropic and lyotropic self-organising properties of four series of monosubstituted methyl α-D-glucopyranoside hydroxyalkyl ethers were investigated in terms of the hydrophobic–hydrophilic balance (see figure). The results obtained lead to a new understanding of the forces that drive the formation of condensed soft-matter phases.

    3. Redox Chemistry

      Electron Capture by the Thiyl Radical and Disulfide Bond: Ligand Effects on the Reduction Potential (pages 5050–5060)

      Dr. Goedele Roos, Prof. Frank De Proft and Prof. Paul Geerlings

      Version of Record online: 20 FEB 2013 | DOI: 10.1002/chem.201203188

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      Same ligand, different effect! Ligand effects on electron capture by the thiyl radical and disulfide bond are determined by the vertical electron affinity A and reorganization energy Ereorganization (see figure). Non-polar ligands decrease the reduction potential E°, whereas polar ligands increase it. Charged ligands favour electron capture by the thiyl radical while disfavouring electron uptake by the disulfide bond.

    4. Metallofullerenes

      Bingel–Hirsch Addition on Endohedral Metallofullerenes: Kinetic Versus Thermodynamic Control (pages 5061–5069)

      Núria Alegret, Dr. Antonio Rodríguez-Fortea and Prof. Josep M. Poblet

      Version of Record online: 19 FEB 2013 | DOI: 10.1002/chem.201203522

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      Fuller control: The Bingel–Hirsch addition on nitride endohedral metallofullerenes has been thoroughly analyzed by using DFT methodology, including solvent effects. Structures that satisfy the isolated pentagon rule (IPR)- and non-IPR structures are both predicted to have analogous reaction paths leading to [6,6] open-cage fulleroids under kinetic control (see figure), which is in good agreement with the experimental results.

    5. Coordination Chemistry

      Regioselective Sequential Additions of Nucleophiles and Electrophiles to Perfluoroalkylfullerenes: Which Cage C Atoms Are the Most Reactive and Why? (pages 5070–5080)

      Tyler T. Clikeman, Dr. Igor V. Kuvychko, Dr. Natalia B. Shustova, Dr. Yu-Sheng Chen, Dr. Alexey A. Popov, Dr. Olga V. Boltalina and Prof. Steven H. Strauss

      Version of Record online: 18 FEB 2013 | DOI: 10.1002/chem.201203571

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      Regioselective sequential additions of CH3 or CN and the electrophiles CH3+, H+, or CN+ are reported for three perfluoroalkylfullerenes, p-C60(CF3)2, Cs-C70(CF3)8, and C1-C70(CF3)10, including the structures of Cs-p9o(loop)-C70(CF3)8(CN)2 and C70(CF3)10(CH3)2(CN)2 (see figure).

    6. Molecular Recognition

      A Self-Assembled Luminescent Host That Selectively Senses ATP in Water (pages 5081–5087)

      Dr. Haslina Ahmad, Benedict W. Hazel, Dr. Anthony J. H. M. Meijer, Dr. Jim A. Thomas and Dr. Karl A. Wilkinson

      Version of Record online: 20 FEB 2013 | DOI: 10.1002/chem.201203603

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      Lit up by ATP: Self-assembled heterometallic macrocycles that are luminescent hosts for nucleotide anions in water are reported. Although the complexes show only a slight binding preference for adenosine triphosphate (ATP) over guanosine triphosphate (GTP), by judicious selection of ancillary ligands, a sensor that displays an “off–on” response for ATP (but not GTP) has been synthesised. Demanding DFT calculations provide evidence for the structural and electronic basis of this effect (see figure).

    7. Electrochemistry

      Terminal Redox-Site Effect on the Long-Range Electron Conduction of Fe(tpy)2 Oligomer Wires on a Gold Electrode (pages 5088–5096)

      Shunsuke Katagiri, Dr. Ryota Sakamoto, Hiroaki Maeda, Dr. Yoshihiko Nishimori, Tomochika Kurita and Prof. Dr. Hiroshi Nishihara

      Version of Record online: 19 FEB 2013 | DOI: 10.1002/chem.201203913

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      Chain gang: The effect of the terminal redox sites on long-range electron conduction in Fe(tpy)2 oligomer wires was investigated (see figure). The attenuation factor βd was independent of the terminal ligands Tx (x=1–3). However, ligand T3 gave rise to a greater zero-distance electron-transfer rate constant, ket0, than those of T1 and T2 due to differences in the reorganization energy of Tx.

    8. Magnetic Materials

      Decametallic CoII-Cluster-Based Microporous Magnetic Framework with a Semirigid Multicoordinating Ligand (pages 5097–5103)

      Jumei Tian, Wenliang Li, Dr. Bo Li, Xiaoying Zhang, Prof. Jinkui Tang and Prof. Jingping Zhang

      Version of Record online: 28 FEB 2013 | DOI: 10.1002/chem.201204458

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      1st and 10: A microporous magnetic framework has been assembled, with a NaCl-like topology net that is based on [Co10] clusters as nodes. This framework shows canted antiferromagnetism and spin-glass behavior.

    9. Luminescence

      Solid-State Luminescence of Au[BOND]Cu[BOND]Alkynyl Complexes Induced by Metallophilicity-Driven Aggregation (pages 5104–5112)

      Dr. Igor O. Koshevoy, Yuh-Chia Chang, Dr. Antti J. Karttunen, Julia R. Shakirova, Prof. Janne Jänis, Prof. Matti Haukka, Prof. Tapani Pakkanen and Prof. Pi-Tai Chou

      Version of Record online: 21 FEB 2013 | DOI: 10.1002/chem.201204611

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      All together now: Upon crystallization, the homoleptic Au[BOND]Cu[BOND]alkynyl complexes aggregate into polymeric chains through Au[BOND]Au bonding, with a dramatic enhancement in room-temperature phosphorescence to a maximum quantum efficiency of 95 %.

    10. Core–Shell Structures

      Enhancing Photoactivity of TiO2(B)/Anatase Core–Shell Nanofibers by Selectively Doping Cerium Ions into the TiO2(B) Core (pages 5113–5119)

      Prof. Dongjiang Yang, Dr. Jian Zhao, Dr. Hongwei Liu, Dr. Zhanfeng Zheng, Dr. Moses O. Adebajo, Dr. Hongxia Wang, Prof. Xiaotang Liu, Prof. Hongjie Zhang, Prof. Jin-cai Zhao, Prof. John Bell and Prof. Huaiyong Zhu

      Version of Record online: 18 FEB 2013 | DOI: 10.1002/chem.201202719

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      Caught in a trap: Cerium ions (Ce3+) can be selectively doped into the TiO2(B) core of TiO2(B)/anatase core–shell nanofibers. The doped Ce3+ ions are located on the (110) plane of TiO2(B) by inserting them into the tunnels perpendicular to the (010) plane (see figure). They can trap the photogenerated holes by the formation of Ce4+ ions, and contribute to separation of photogenerated charges in the anatase shell.

    11. Photoredox Catalysis

      Visible-Light Photocatalytic Radical Alkenylation of α-Carbonyl Alkyl Bromides and Benzyl Bromides (pages 5120–5126)

      Dr. Qiang Liu, Hong Yi, Jie Liu, Yuhong Yang, Xu Zhang, Ziqi Zeng and Prof. Aiwen Lei

      Version of Record online: 20 FEB 2013 | DOI: 10.1002/chem.201203694

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      Light work: A mechanistically distinct method was developed to achieve the alkenylation of various α-carbonyl alkyl bromides and benzyl bromides under mild conditions (see scheme).

    12. Nanocrystals

      Aqueous-Phase Synthesis of Single-Crystal Pd Seeds 3 nm in Diameter and Their Use for the Growth of Pd Nanocrystals with Different Shapes (pages 5127–5133)

      Cun Zhu, Prof. Jie Zeng, Dr. Ping Lu, Prof. Jingyue Liu, Prof. Zhongze Gu and Prof. Younan Xia

      Version of Record online: 18 FEB 2013 | DOI: 10.1002/chem.201203787

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      Simple, green, efficient: Starting from Pd single-crystal seeds 3 nm in size, Pd nanocrystals, with a variety of shapes, including polyhedra and plates, were obtained by simply varying the concentration of KBr added to aqueous solutions used for seed-mediated growth (see figure).

    13. Asymmetric Synthesis

      Nickel(II)-Catalyzed Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Imines with Alkylidene Malonates (pages 5134–5140)

      Jiangting Li, Xiangjin Lian, Prof. Dr. Xiaohua Liu, Lili Lin and Prof. Dr. Xiaoming Feng

      Version of Record online: 27 FEB 2013 | DOI: 10.1002/chem.201203891

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      Pyrazolone products: The asymmetric [3+2] dipolar cycloaddition of azomethine imines with alkylidene malonates was catalyzed by an N,N′-dioxide L4–nickel(II) complex (see scheme; Bn=benzyl). A wide variety of trans products were generated as single diastereomers in good yields and with excellent enantioselectivities. The reaction is one of the most ideal strategies to construct five-membered N,N-bicyclic derivatives.

    14. Click Chemistry

      “Clickable” Vitamin B12 Derivative (pages 5141–5148)

      Mikołaj Chromiński and Prof. Dorota Gryko

      Version of Record online: 16 JAN 2013 | DOI: 10.1002/chem.201203899

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      Doing the two-step: A “clickable” vitamin B12 derivative possessing the azide functionality at the 5′-position was synthesized by means of a two-step procedure on the gram scale (see scheme). This compound proved to be reactive in the azide–alkyne cycloaddition reaction to give substituted triazoles in high yields.

    15. Aromatic Compounds

      Does the Molecular Electrostatic Potential Reflect the Effects of Substituents in Aromatic Systems? (pages 5149–5155)

      Prof. Boris Galabov, Dr. Valia Nikolova and Prof. Sonia Ilieva

      Version of Record online: 27 FEB 2013 | DOI: 10.1002/chem.201204092

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      Bags of potential: Theoretically evaluated electrostatic potentials in close proximity to the ring carbon atoms correlate excellently with reactivity constants and reflect both through-space and resonance effects of substituents in aromatic systems (see figure).

    16. Chiral Self-Assembly

      Stereodynamics of Metal–Ligand Assembly: What Lies Beneath the “Simple” Spectral Signatures of C2-Symmetric Chiral Chelates (pages 5156–5168)

      Dr. Jiyoung Jung, Junyong Jo, Moitree Laskar and Prof. Dr. Dongwhan Lee

      Version of Record online: 28 FEB 2013 | DOI: 10.1002/chem.201204216

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      A revolving door? Chiral auxiliaries installed onto conformationally pre-organised “Dutch-door-type” ligands allow for detailed spectroscopic studies to unravel the mechanisms of self-assembly, chirality switching, and the functional role of π-conjugated ligand architecture in solution (see scheme).

    17. Graphene

      CeO2-Based Pd(Pt) Nanoparticles Grafted onto Fe3O4/Graphene: A General Self-Assembly Approach To Fabricate Highly Efficient Catalysts with Magnetic Recyclable Capability (pages 5169–5173)

      Xiao Wang, Dapeng Liu, Shuyan Song and Prof. Dr. Hongjie Zhang

      Version of Record online: 5 MAR 2013 | DOI: 10.1002/chem.201204302

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      Stick together: A general approach to fabricate highly efficient ceria-based catalysts with magnetic recyclable capability by self-assembling Fe3O4 and CeO2/Pd (Pt) on the surface of graphene oxide (GO) is demonstrated. The as-obtained catalysts show relatively high catalytic activity and stability in the selective hydrogenation of nitrobenzene (see figure).

    18. Biginelli Reaction

      The Combined Role of Catalysis and Solvent Effects on the Biginelli Reaction: Improving Efficiency and Sustainability (pages 5174–5182)

      Prof. James H. Clark, Dr. Duncan J. Macquarrie and James Sherwood

      Version of Record online: 21 FEB 2013 | DOI: 10.1002/chem.201204396

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      Cause and effect: Solvent polarity determines the position of the diketo–enol tautomerisation equilibrium of 1,3-dicarbonyl compounds. This in turn dictates the yield of the Biginelli reaction by means of an acid-catalysed condensation with urea and benzaldehyde that proceeds through the enol tautomer of methyl acetoacetate or 5,5-dimethyl-1,3-cyclohexanedione (see figure).

    19. Lithium Ion Batteries

      Multifunctional Co3S4/Graphene Composites for Lithium Ion Batteries and Oxygen Reduction Reaction (pages 5183–5190)

      Nasir Mahmood, Chenzhen Zhang, Jie Jiang, Fei Liu and Prof. Yanglong Hou

      Version of Record online: 27 FEB 2013 | DOI: 10.1002/chem.201204549

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      Composite electrodes: Co3S4/graphene composites have been synthesized as a new material for electrodes by a facile hydrothermal process (see figure). The composites show a very high performance as an anode material in lithium ion batteries with an initial discharge of 2151 mA h g−1. In the oxygen reduction reaction (ORR), the composites exhibit much better stability and higher methanol tolerance than Pt/C as well as an onset potential close to that of Pt/C.

    20. Stable Phosphovanadoniobates

      A Soluble Phosphorus-Centered Keggin Polyoxoniobate with Bicapping Vanadyl Groups (pages 5191–5197)

      Dr. Jung-Ho Son, Dr. C. André Ohlin, Rene L. Johnson, Dr. Ping Yu and Prof. William H. Casey

      Version of Record online: 27 FEB 2013 | DOI: 10.1002/chem.201204563

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      A phosphorus-centered and vanadyl-bicapped Keggin polyoxoniobate, [PV2Nb12O42]9−, has been synthesized and structurally characterized (see picture) as a soluble tetramethylammonium salt, TMA9[PV2Nb12O42]⋅19H2O. The cluster is stable in the pH range 4–10 and under hydrothermal conditions. Its stability was established by 31P and 51V NMR and UV/Vis spectroscopy, and ESI-MS.

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