Chemistry - A European Journal

Cover image for Vol. 18 Issue 12

March 19, 2012

Volume 18, Issue 12

Pages 3421–3783

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Communications
    7. Full Papers
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    1. You have free access to this content
      Cover Picture: A New Piece in the Puzzle of Lithium/Air Batteries: Computational Study on the Chemical Stability of Propylene Carbonate in the Presence of Lithium Peroxide (Chem. Eur. J. 12/2012) (page 3421)

      Dr. Teodoro Laino and Dr. Alessandro Curioni

      Version of Record online: 13 MAR 2012 | DOI: 10.1002/chem.201290042

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      A new type of battery made of a lithium anode and a porous cathode has attracted attention in recent years because of the large impact this technology may have on several fields, including electric mobility. In this context, the electrolyte role in non-aqueous lithium/air batteries emerged as a fundamental issue, the choice of the solvent being a key factor to achieve the highest possible energy density, while allowing the rechargeability of the cell. In the Full Paper on page 3510 ff., T. Laino and A. Curioni describe, with first principle methods, the chemical degradation of the propylene carbonate exposed to a layer of lithium oxide (in the picture, on top of an additional layer of porous material).

  2. Graphical Abstract

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

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

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Communications
    7. Full Papers
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    1. Enzyme Assays

      Supramolecular Tandem Enzyme Assays (pages 3444–3459)

      Dr. Roy N. Dsouza, Dr. Andreas Hennig and Prof. Dr. Werner M. Nau

      Version of Record online: 24 FEB 2012 | DOI: 10.1002/chem.201103364

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      The combination of macrocycles with fluorescent dyes affords supramolecular reporter pairs, which can be employed for the monitoring of catalytic, particularly biocatalytic, reactions. The resulting assays are unselective time-resolved variants of indicator displacement and uptake sensing systems. They are applicable to a large range of analytes and allow direct real-time monitoring in homogeneous solution, with the possibility of performing inhibitor and catalyst screening.

  5. Communications

    1. Top of page
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    4. News
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    1. Supramolecular Chemistry

      Charge-Based Assemblies Comprising Planar Receptor–Anion Complexes with Bulky Alkylammonium Cations (pages 3460–3463)

      Dr. Bin Dong, Yoshitaka Terashima, Dr. Yohei Haketa and Prof. Dr. Hiromitsu Maeda

      Version of Record online: 17 FEB 2012 | DOI: 10.1002/chem.201104066

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      Charge-by-charge assembly: On the basis of a planar receptor–anion complex, bulky tetraalkylammonium cations were found to construct charge-by-charge assemblies comprising alternately stacked positively and negatively charged species. The number and length of long alkyl chains in the cations determine the states of assembled structures, resulting in the formation of a library of charge-based materials (see scheme).

    2. Allosterism

      Allosteric Effects in a Ditopic Ligand Containing Bipyridine and Tetra-aza-crown Donor Units (pages 3464–3467)

      Dr. Cara E. Sutton, Dr. Lindsay P. Harding, Dr. Michaele Hardie, Dr. Thomas Riis-Johannessen and Dr. Craig R. Rice

      Version of Record online: 23 FEB 2012 | DOI: 10.1002/chem.201103217

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      Artificial allosterism: A ditopic ligand, which contains both bipyridine and tetra-aza-crown binding sites, coordinates one CuII through all four N-donors of the tetradentate aza-crown unit. Reaction at the bipyridine site with another CuII allosterically changes the aza-crown from being a tetradentate to a tridentate N-donor unit, a change in coordination mode that causes the successive binding of two CuII ions to proceed with severe negative cooperativity (see scheme).

    3. Domino Reactions

      Merging Domino and Redox Chemistry: Stereoselective Access to Di- and Trisubstituted β,γ-Unsaturated Acids and Esters (pages 3468–3472)

      Dr. David Tejedor, Gabriela Méndez-Abt, Leandro Cotos and Dr. Fernando García-Tellado

      Version of Record online: 22 FEB 2012 | DOI: 10.1002/chem.201103763

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      Merging is the game! The coupling of a domino reaction and an internal neutral redox reaction constitutes an excellent manifold for the stereoselective synthesis of di- and trisubstituted olefins featuring a malonate unit, an ester, or a free carboxylic acid as substituents at the allylic position (see scheme; MW=microwave). The reaction utilizes simple starting materials (propargyl vinyl ethers), methanol or water as solvents, and a very simple and bench-friendly protocol.

    4. Asymmetric Catalysis

      Enantioselective Synthesis of β-Pyrazole-Substituted Alcohols through an Asymmetric Ring-Opening Reaction of meso-Epoxides (pages 3473–3477)

      Xiaolei Hu, Dr. Bo Gao, Yangyang Chu, Wei Li, Dr. Xiaohua Liu, Dr. Lili Lin and Prof. Dr. Xiaoming Feng

      Version of Record online: 23 FEB 2012 | DOI: 10.1002/chem.201103792

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      An efficient and practical synthesis of optically pure β-pyrazole-substituted alcohols was achieved by an asymmetric ring-opening reaction of meso-epoxides with pyrazole derivatives as the nucleophile. In the presence of 1 mol % of an N,N′-dioxide–Sc(OTf)3 complex, excellent enantioselectivity and yields were obtained from meso-epoxides. The process could also be used for a mixture of cis- and trans-stilbene oxides. A proposed transition-state model is provided.

    5. Heterogeneous Photocatalysis

      Light-Mediated Heterogeneous Cross Dehydrogenative Coupling Reactions: Metal Oxides as Efficient, Recyclable, Photoredox Catalysts in C[BOND]C Bond-Forming Reactions (pages 3478–3481)

      Prof. Dr. Magnus Rueping, Dipl.-Chem. Jochen Zoller, David C. Fabry, Dipl.-Chem. Konstantin Poscharny, Dipl.-Chem. René M. Koenigs, Priv.-Doz. Dr. Thomas E. Weirich and Prof. Dr. Joachim Mayer

      Version of Record online: 7 FEB 2012 | DOI: 10.1002/chem.201103242

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      Let there be light: A heterogeneous photocatalytic system based on easily recyclable TiO2 or ZnO allows cross dehydrogenative coupling reactions of tertiary amines. The newly developed protocols have successfully been applied to various C[BOND]C and C[BOND]P bond-forming reactions to provide nitro amines as well as amino ketones, nitriles and phosphonates.

    6. C[BOND]O Activation

      Aryl Ether as a Negishi Coupling Partner: An Approach for Constructing C[BOND]C Bonds under Mild Conditions (pages 3482–3485)

      Dr. Chao Wang, Takashi Ozaki, Prof. Dr. Ryo Takita and Prof. Dr. Masanobu Uchiyama

      Version of Record online: 28 FEB 2012 | DOI: 10.1002/chem.201103784

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      An etheric Negishi coupling: The first cross-coupling reaction between aryl alkyl ethers and dianion-type zincate reagents to afford biaryl compounds through selective cleavage of the etheric C(sp2)[BOND]O bond was developed. Dianion-type zincates showed excellent reactivity toward the aromatic ethers under mild conditions, with good functional group compatibility (see scheme).

    7. C[BOND]C Activation

      Regioselective Cycloaddition of 3-Azetidinones and 3-Oxetanones with Alkynes through Nickel-Catalysed Carbon–Carbon Bond Activation (pages 3486–3489)

      Kelvin Y. T. Ho and Dr. Christophe Aïssa

      Version of Record online: 22 FEB 2012 | DOI: 10.1002/chem.201200167

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      Get in the ring! The first examples of transition-metal-catalysed C[BOND]C bond activation of 3-azetidinones and 3-oxetanones are reported. In the presence of a nickel catalyst and alkynes, a regioselective and high-yielding [4+2] cycloaddition occurs, leading to the formation of pyridinones, pyranones and eventually 4,5-disubstituted 3-hydroxypyridines (see scheme).

    8. Boron Chemistry

      A Convenient Synthesis and a NMR Study of the Diammoniate of Diborane (pages 3490–3492)

      Dr. Hima K. Lingam, Dr. Xuenian Chen, Prof. Ji-Cheng Zhao and Prof. Sheldon G. Shore

      Version of Record online: 22 FEB 2012 | DOI: 10.1002/chem.201103693

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      DADB synthesis: The diammoniate of diborane (DADB) was synthesized in a new metathesis reaction between the diammoniate of monochloroborane and potassium borohydride in liquid ammonia (see scheme). 1H and 11B NMR spectra of DADB are reported. The stability in THF was examined by variable-temperature 11B NMR spectroscopy.

    9. Polyoxometalates

      The {V4Nb6O30} Cluster: A New Type of Vanadoniobate Anion Structure (pages 3493–3497)

      Dr. Guiling Guo, Dr. Yanqing Xu, Jie Cao and Prof. Changwen Hu

      Version of Record online: 23 FEB 2012 | DOI: 10.1002/chem.201103390

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      A novel {V4Nb6O30} addenda: Through the successful introduction of a vanadium atom into the polyoxoniobate system, three novel compounds containing the same unprecedented mixed addenda vanadoniobate cluster {V4Nb6O30} were obtained. The incorporation of suitable atoms like V is an intriguing subject providing vast possibilities to enrich polyoxoniobate chemistry.

  6. Full Papers

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

      Tetrachlorinated Tetraazaperopyrenes (TAPPs): Highly Fluorescent Dyes and Semiconductors for Air-Stable Organic n-Channel Transistors and Complementary Circuits (pages 3498–3509)

      Dr. Susanne C. Martens, Dr. Ute Zschieschang, Prof. Dr. Hubert Wadepohl, Dr. Hagen Klauk and Prof. Dr. Lutz H. Gade

      Version of Record online: 22 FEB 2012 | DOI: 10.1002/chem.201103158

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      TAPPing the potential: Perfluoroalkylation and core chlorination gives rise to tetraazaperopyrenes (TAPPs) with high-performance in n-channel transistors (see figure; field-effect mobility of up to 0.14 cm2 V−1 s−1, on/off current ratio of >106 and stabilities of up to 3–4 months under ambient conditions).

    2. Lithium Batteries

      A New Piece in the Puzzle of Lithium/Air Batteries: Computational Study on the Chemical Stability of Propylene Carbonate in the Presence of Lithium Peroxide (pages 3510–3520)

      Dr. Teodoro Laino and Dr. Alessandro Curioni

      Version of Record online: 22 FEB 2012 | DOI: 10.1002/chem.201103057

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      The main culprit for the degradation of propylene carbonate (PC) in batteries has been identified as Li2O2. The reactivity of lithium peroxide versus propylene carbonate has been investigated (see figure) and it was found that Li2O2 irreversibly decomposes the carbonate solvent, leading to alkyl carbonates; compared with a single Li2O2 unit in PC, a crystalline surface of Li2O2 exhibits an enhanced reactivity.

    3. Enzyme Assays

      A Fluorescence-Based Supramolecular Tandem Assay for Monitoring Lysine Methyltransferase Activity in Homogeneous Solution (pages 3521–3528)

      Dr. Mara Florea, Dr. Srikanth Kudithipudi, Dr. Ana Rei, María José González-Álvarez, Prof. Dr. Albert Jeltsch and Prof. Dr. Werner M. Nau

      Version of Record online: 24 FEB 2012 | DOI: 10.1002/chem.201103397

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      The methylation of peptides by histone lysine methyltransferases, the enzymes responsible for epigenetic regulation, can be continuously monitored in homogeneous solution by using a label-free supramolecular tandem assay strategy. The high affinity of the trimethylated enzymatic product towards p-sulfonatocalix[4]arene, used in combination with the displacement of lucigenin as a dye, allows for a time-resolved switch-ON fluorescence response as a fingerprint of the catalytic activity (see figure).

    4. Carbocycles

      Asymmetric Synthesis of Densely Functionalized Medium-Ring Carbocycles and Lactones through Modular Assembly and Ring-Closing Metathesis of Sulfoximine-Substituted Trienes and Dienynes (pages 3529–3548)

      Dr. Michal Lejkowski, Prof. Dr. Prabal Banerjee, Dipl.-Chem. Sabine Schüller, Dipl.-Chem. Alexander Münch, Dr. Jan Runsink, Cornelia Vermeeren and Prof. Dr. Hans-Joachim Gais

      Version of Record online: 16 FEB 2012 | DOI: 10.1002/chem.201103060

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      High density: Asymmetric syntheses of densely functionalized 7–11-membered carbocycles, fused 6/9- and 6/11-membered bicyclic carbocycles, and 9–11-membered lactones are described (see scheme). The key steps are modular syntheses of sulfoximine-substituted C- and O-tethered trienes and dienynes and their Ru-catalyzed ring-closing diene and enyne methasis (RCOEM and RCEYM), respectively. RCEYM of a sulfoximine-substituted 1,7-dien-10-yne with first- and second-generation Ru catalysts showed an unprecedented dichotomy and gave a 9-membered 1,3-dienyl carbocycle and a 9-membered 1,3-dienyl carbocycle truncated by one CH2 unit.

    5. Logic Gates

      A Smart Gelator as a Chemosensor: Application to Integrated Logic Gates in Solution, Gel, and Film (pages 3549–3558)

      Dr. Pengchong Xue, Prof. Ran Lu, Junhui Jia, Dr. Makoto Takafuji and Prof. Hirotaka Ihara

      Version of Record online: 23 FEB 2012 | DOI: 10.1002/chem.201103566

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      Highly logical, captain: Logic gates were constructed from a gelator, which was responsive to protons and anions, in its solution, gel, and film states. The output of the logic gates were recorded by the naked eye and UV/Vis and fluorescence spectroscopy (see figure).

    6. Phase Diagrams

      Theoretical and Experimental Exploration of the Energy Landscape of the Quasi-Binary Cesium Chloride/Lithium Chloride System (pages 3559–3565)

      Dr. Ilya V. Pentin, Dr. Vyacheslav Saltykov, Dr. Jürgen Nuss, Prof. Dr. J. Christian Schön and Prof. Dr. Dr. h. c. Martin Jansen

      Version of Record online: 23 FEB 2012 | DOI: 10.1002/chem.201103162

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      Landscape gardening: The energy landscape of the cesium chloride/lithium chloride system was explored by combining theoretical and experimental methods. Owing to the synergetic and complementary nature of these approaches, substantially improved efficiency of the exploration was achieved. Several new phases were found in this system and their thermodynamic ranking was clarified, thereby leading to the derivation of an improved CsCl/LiCl phase diagram.

    7. Porphyrins

      Synthesis, Characterization, and Spectroscopic Analysis of Antiaromatic Benzofused Metalloporphyrins (pages 3566–3581)

      Shun Sugawara, Yusuke Hirata, Dr. Satoshi Kojima, Prof. Yohsuke Yamamoto, Dr. Eigo Miyazaki, Prof. Kazuo Takimiya, Dr. Shiro Matsukawa, Dr. Daisuke Hashizume, Dr. John Mack, Prof. Nagao Kobayashi, Zhen Fu, Prof. Karl M. Kadish, Young Mo Sung, Dr. Kil Suk Kim and Prof. Dongho Kim

      Version of Record online: 14 FEB 2012 | DOI: 10.1002/chem.201101846

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      Sweet 16: Copper(II) and zinc(II) benzofused porphyrin complexes with 16π-electron cores were prepared through two-electron oxidation of tetraphenyltetrabenzoporphyrin complexes with AgSbF6 (see scheme). Structural characterization and a variety of spectroscopic studies were carried out to analyze the electronic structure and study key trends in the antiaromatic properties of these novel 16π-electron porphyrin species.

    8. Cytochromes

      Identification of Mutant Asp251Gly/Gln307His of Cytochrome P450 BM3 for the Generation of Metabolites of Diclofenac, Ibuprofen and Tolbutamide (pages 3582–3588)

      Dr. Georgia E. Tsotsou, Dr. Anastasia Sideri, Dr. Abhineet Goyal, Dr. Giovanna Di Nardo and Prof. Gianfranco Gilardi

      Version of Record online: 15 FEB 2012 | DOI: 10.1002/chem.201102470

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      Soluble bacterial P450: The mutant Asp251Gly/Gln307His of the bacterial cytochrome P450 BM3 shows new catalytic activity towards diclofenac, ibuprofen and tolbutamide. It can be used to synthesise the metabolites of these drugs normally produced by the 2C subfamily of human cytochromes P450 (see scheme).

    9. DNA Recognition

      Dimeric Calixarenes: A New Family of Major-Groove Binders (pages 3589–3597)

      Dr. Wenbin Hu, Dr. Caroline Blecking, Dr. Marijeta Kralj, Dr. Lidija Šuman, Dr. Ivo Piantanida and Prof. Dr. Thomas Schrader

      Version of Record online: 15 FEB 2012 | DOI: 10.1002/chem.201100634

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      Get into the (major) groove! Dimeric calix[4]arenes with cationic groups at their upper rims and flexible alkyl bridges have been synthesized in relatively short synthetic sequences (3–5 steps). The compounds attach themselves to the major groove of double-stranded nucleic acids in a noncovalent fashion (see figure; red), with micro- to nanomolar affinities.

    10. Total Synthesis

      Total Synthesis of Bafilomycin A1 (pages 3598–3610)

      Florian Kleinbeck, Gabriela J. Fettes, Dr. Lee D. Fader and Prof. Dr. Erick M. Carreira

      Version of Record online: 16 FEB 2012 | DOI: 10.1002/chem.201102797

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      Tying the knot: A convergent synthesis of bafilomycin A1 is presented. The synthesis relies on the zinc triflate mediated diastereoselective addition of a complex enyne to a sensitive aldehyde as the key fragment coupling. A ruthenium-catalyzed trans-reduction of the resulting propargylic enyne efficiently installs the required C10–C13 trans,trans-diene subunit.

    11. Substituent Effects

      An Experimental Study on the Effect of Substituents on Aromatic–Aromatic Interactions in Dithia[3,3]-metaparacyclophanes (pages 3611–3620)

      Dr. Jian Long Xia, Prof. Sheng Hua Liu, Prof. Franco Cozzi, Dr. Michele Mancinelli and Prof. Andrea Mazzanti

      Version of Record online: 9 FEB 2012 | DOI: 10.1002/chem.201103639

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      Off the subs bench: 2,11-Dithia[3,3]-metaparacyclophanes were designed and synthesized to study the effect of substituents on the intramolecular aromatic–aromatic interactions between benzene rings. The energy barriers to topomerization were determined by variable-temperature NMR spectroscopy. The variation of the barriers as a function of the substitution on the interacting ring was not related to their effect on the polarity of the π-systems.

    12. A New Class of Organosuperbases, N-Alkyl- and N-Aryl-1,3-dialkyl-4,5-dimethylimidazol-2-ylidene Amines: Synthesis, Structure, pKBH+ Measurements, and Properties (pages 3621–3630)

      Roman A. Kunetskiy, Dr. Svetlana M. Polyakova, Jiří Vavřík, Dr. Ivana Císařová, Jaan Saame, Eva Roos Nerut, Dr. Ivar Koppel, Prof. Ilmar A. Koppel, Dr. Agnes Kütt, Prof. Ivo Leito and Dr. Ilya M. Lyapkalo

      Version of Record online: 14 FEB 2012 | DOI: 10.1002/chem.201102249

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      Bases coming on strong: A series of stable organosuperbases, N-alkyl- and N-aryl-1,3-dialkyl-4,5-dimethylimidazol-2-ylidene amines, were efficiently synthesized and their basicities were measured in acetonitrile, some of which are stronger bases than the phosphazene base (shown right) and tetramethylguanidine (shown left) in acetonitrile. The basicity depends on, among other factors, the size of the substituent at the imino group, which influences the degree of aromatization of the imidazole ring.

    13. Aggregation

      Isolable Chiral Aggregates of Achiral π-Conjugated Carboxylic Acids (pages 3631–3636)

      Dr. Jin-Song Zhao, Jin-He Wang, Wen-Bin He, Yi-Bin Ruan and Prof. Dr. Yun-Bao Jiang

      Version of Record online: 10 FEB 2012 | DOI: 10.1002/chem.201103651

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      Together forever: A method for the synthesis of isolable chiral aggregates of achiral building blocks was developed and used for the isolation of the chiral homoaggregates of neutral achiral π-conjugated carboxylic acids in pure aqueous solutions.

    14. Cluster Compounds

      Triangular Nickel Complexes Derived from 2-Pyridylcyanoxime: An Approach to the Magnetic Properties of the [Ni33-OH){pyC(R)NO}3]2+ Core (pages 3637–3648)

      Jordi Esteban, Prof. Eliseo Ruiz, Dr. Mercé Font-Bardia, Dr. Teresa Calvet and Prof. Albert Escuer

      Version of Record online: 15 FEB 2012 | DOI: 10.1002/chem.201102987

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      Triangulation: Experimental and DFT calculations reveal the magnetic response of triangular NiII–oximato systems (see figure). The magnetic properties of several Ni3, Ni4 and Ni5 complexes with topologies based on isolated, edge- or vertex-sharing triangular μ3-OR nickel–oximate units have been elucidated and compared with analogous copper or manganese systems.

    15. Asymmetric Catalysis

      Unifying Metal- and Organocatalysis for Asymmetric Oxidative Iminium Activation: A Relay Catalytic System Enabling the Combined Allylic Oxidation of Alcohols and Prolinol Ether Catalyzed Iminium Reactions (pages 3649–3653)

      Prof. Dr. Magnus Rueping, Dr. Henrik Sundén and Dr. Erli Sugiono

      Version of Record online: 28 FEB 2012 | DOI: 10.1002/chem.201102551

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      Multitasking: A multicatalytic system, consisting of tetrapropylammonium perruthenate/N-methylmorpholine N-oxide (TPAP/NMO) as oxidant and diarylprolinol TMS-ether as chiral amine catalyst, has been developed and applied in the efficient construction of valuable chiral molecules, such as formylcyclopropanes, β-substituted aldehydes, and chromenone derivatives.

    16. Catalysis

      Silver(I)-Catalyzed Tandem 1,3-Acyloxy Migration/Mannich-type Addition/Elimination of the Sulfonyl Group of N-Sulfonylhydrazone-propargylic Esters to 5,6-Dihydropyridazin-4-one Derivatives (pages 3654–3658)

      Zhen Zhang and Min Shi

      Version of Record online: 22 FEB 2012 | DOI: 10.1002/chem.201103404

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      An efficient route for the synthesis of 5,6-dihydropyridazin-4-one derivatives through a silver-catalyzed intramolecular tandem reaction of N-sulfonylhydrazone-propargylic esters has been disclosed. The reaction proceeds through a tandem 1,3-acyloxy migration/Mannich-type addition/elimination of a sulfonyl group sequence (see scheme).

    17. Heterometallic Compounds

      Luminescent Di- and Polynuclear Organometallic Gold(I)–Metal (Au2, {Au2Ag}n and {Au2Cu}n) Compounds Containing Bidentate Phosphanes as Active Antimicrobial Agents (pages 3659–3674)

      Malgorzata Frik, Dr. Josefina Jiménez, Ismael Gracia, Prof. Larry R. Falvello, Sarya Abi-Habib, Karina Suriel, Prof. Theodore R. Muth and Prof. María Contel

      Version of Record online: 14 FEB 2012 | DOI: 10.1002/chem.201103145

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      Two trumps one! A synergistic antimicrobial effect between gold and silver is found in novel polynuclear {Au2Ag}n heterometallic compounds. The luminescence of these and related tri- Au2Cu and dinuclear Au2 organometallic derivatives has been studied and correlated with crystallographic data and metallophilic interactions. Most complexes display antibacterial activity, with Au2Ag being highly active against Gram-positive and Gram-negative bacteria (see scheme).

    18. Imaging Agents

      Serum Albumin Targeted, pH-Dependent Magnetic Resonance Relaxation Agents (pages 3675–3686)

      Dr. Loïck Moriggi, Dr. Mohammad A. Yaseen, Prof. Lothar Helm and Prof. Peter Caravan

      Version of Record online: 10 FEB 2012 | DOI: 10.1002/chem.201103344

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      Whither the water? The GdIII MRI contrast agent shown has a pH-dependent relaxivity due to a change in inner-sphere hydration (q=2 to q=0) upon sulfonamide coordination. The biphenyl moiety imparts strong affinity for serum albumin, and protein binding was expected to increase pH-dependent relaxivity further. However, the inner-sphere waters are displaced when the complex binds albumin at low pH, and the pH-dependent relaxivity effect is muted.

    19. Materials Science

      Temperature-Responsive Polymer/Carbon Nanotube Hybrids: Smart Conductive Nanocomposite Films for Modulating the Bioelectrocatalysis of NADH (pages 3687–3694)

      Xin Zhao, Dr. Yang Liu, Jin Lu, Dr. Jianhua Zhou and Prof. Jinghong Li

      Version of Record online: 14 FEB 2012 | DOI: 10.1002/chem.201103259

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      Smart catalysis! A temperature-sensitive polymer/carbon nanotube composite film with high conductivity and electrocatalytic activity was fabricated on a gold surface (see figure). The modulation of bioelectrocatalysis and electron transfer of biomolecules were achieved on the film.

    20. Mesoporous Materials

      Fabrication of Mesoporous Metal Chalcogenide Nanoflake Silica Thin Films and Spongy Mesoporous CdS and CdSe (pages 3695–3705)

      Yurdanur Türker, Cüneyt Karakaya and Prof. Ömer Dag

      Version of Record online: 16 FEB 2012 | DOI: 10.1002/chem.201102643

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      A new approach for the fabrication of mesoporous metal chalcogenide silica thin films and their conversion into mesoporous metal chalcogenides has been demonstrated. The metal precursors have been incorporated into the pore walls through a salt-assisted self-assembly process that produces homogenous metal oxide coatings over the pore walls of the mesoporous silica thin films (see figure).

    21. Azo Compounds

      Decoupling Fluorescence and Photochromism in Bifunctional Azo Derivatives for Bulk Emissive Structures (pages 3706–3720)

      Dr. Aurélie Jacquart, Dr. René M. Williams, Prof. Albert M. Brouwer and Prof. Eléna Ishow

      Version of Record online: 9 FEB 2012 | DOI: 10.1002/chem.201103411

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      Dual photoinduced action: The introduction of a rigid triptycenyl-like spacer between a photochromic azo unit and a fluorescent unit allow both moieties to keep their photophysical integrity ruled by picosecond dynamics in the excited state (see figure). This leads to fluorescent patterns in thin films that are subjected to interferential illumination.

    22. Gold Catalysis

      The More Gold—The More Enantioselective: Cyclohydroaminations of γ-Allenyl Sulfonamides with Mono-, Bis-, and Trisphospholane Gold(I) Catalysts (pages 3721–3728)

      Dr. Lara-Isabel Rodríguez, Dipl.-Chem. Torsten Roth, Dr. Julio Lloret Fillol, Prof. Dr. Hubert Wadepohl and Prof. Dr. Lutz H. Gade

      Version of Record online: 23 FEB 2012 | DOI: 10.1002/chem.201103140

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      The golden touch: Higher enantioselectivities were observed upon increasing the catalyst nuclearity, by combining symmetry-equivalent sites for a series of chiral gold(I) catalysts. The C3-symmetric trinuclear catalyst surpassed its mono- and dinuclear congeners both in terms of activity and enantioselectivity.

    23. Lipopolysaccharides

      Characterization of the Core Oligosaccharide and the O-Antigen Biological Repeating Unit from Halomonas stevensii Lipopolysaccharide: The First Case of O-Antigen Linked to the Inner Core (pages 3729–3735)

      Dr. Giuseppina Pieretti, Sara Carillo, Dr. Buko Lindner, Kwang Kyu Kim, Keun Chul Lee, Jung-Sook Lee, Prof. Dr. Rosa Lanzetta, Prof. Dr. Michelangelo Parrilli and Prof. Dr. Maria Michela Corsaro

      Version of Record online: 14 FEB 2012 | DOI: 10.1002/chem.201102550

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      Bacterial inspection: In this paper, the complete saccharidic structure of the lipopolysaccharide (LPS) that belongs to the human pathogen Halomonas stevensii bacterium is reported. The tridecasaccharide that contained the core region plus one O-chain repeating unit was obtained and characterized (see scheme).

    24. Photochemistry

      Photoprotection and the Photophysics of Acylated Anthocyanins (pages 3736–3744)

      Palmira Ferreira da Silva, Luísa Paulo, Arianna Barbafina, Fausto Elisei, Frank H. Quina and António L. Maçanita

      Version of Record online: 14 FEB 2012 | DOI: 10.1002/chem.201102247

      Thumbnail image of graphical abstract

      Photoprotection in plants: The acylation of anthocyanins provides UV protection against photochemical damage by fast energy transfer (ET) from the excited co-pigment (Coum) to the anthocyanin (Cy) followed by ultrafast adiabatic proton transfer (PT) to water or internal conversion (IC) of the complex (see figure).

    25. Nanostructures

      Selected-Control Fabrication of Multifunctional Fluorescent–Magnetic Core–Shell and Yolk–Shell Hybrid Nanostructures (pages 3745–3752)

      Haiyan Liu, Dr. Tingting Wang, Lingyu Zhang, Lu Li, Dr.  Y. Andrew Wang, Prof. Dr. Chungang Wang and Prof. Dr. Zhongmin Su

      Version of Record online: 10 FEB 2012 | DOI: 10.1002/chem.201103066

      Thumbnail image of graphical abstract

      In their shells: Uniform core–shell and yolk–shell architectures (see figure), which combine the functions of a superparamagnetic iron oxide (SPIO) core and a europium-doped yttrium oxide (Y2O3:Eu) shell in a single material with tunable fluorescence and magnetic properties, are prepared. The shell thickness and interior cavity of SPIO@Y2O3:Eu nanostructures can also be tuned. Yolk–shell nanocapsules modified with amino groups serve as cancer-cell fluorescence imaging agents.

    26. Amino Acids

      Stereoselective Access to Fluorinated and Non-fluorinated Quaternary Piperidines: Synthesis of Pipecolic Acid and Iminosugar Derivatives (pages 3753–3764)

      Prof. Dr. Santos Fustero, Dr. Laia Albert, Natalia Mateu, Dr. Gema Chiva, Javier Miró, Prof. Dr. Javier González and Dr. José Luis Aceña

      Version of Record online: 14 FEB 2012 | DOI: 10.1002/chem.201102351

      Thumbnail image of graphical abstract

      Making it sweet: A series of 2,2,6-trisubstituted piperidines containing a trifluoromethyl or alkyl group at the α position are prepared from a chiral imino lactone by employing two different synthetic strategies. The final products constitute quaternary derivatives of pipecolic acid, and fluorinated analogues of iminosugars can also be conveniently accessed (see scheme; TASF=tris(dimethylamino)sulfonium difluorotrimethylsilicate, TMSCF3=(trifluoromethyl)trimethylsilane).

    27. Biosensors

      Hetero-oligophenylene-Based AIEE Material as a Multiple Probe for Biomolecules and Metal Ions to Construct Logic Circuits: Application in Bioelectronics and Chemionics (pages 3765–3772)

      Dr. Vandana Bhalla, Varun Vij, Abhimanew Dhir and Dr. Manoj Kumar

      Version of Record online: 10 FEB 2012 | DOI: 10.1002/chem.201103131

      Thumbnail image of graphical abstract

      A propeller-shaped hetero-oligophenylene derivative, which exhibits aggregation-induced emission enhancement in H2O/THF (80:20) was synthesized. The aggregates serve as a biological probe for three different proteins (bovine serum albumin (BSA), cytochrome c, and lysozyme), DNA, and two metal ions (Pb2+ and Pd2+) in contrasting modes. The fluorescence behavior between BSA and cytochrome c and between Pb2+ and Pd2+ ions mimics the performance of combinatorial logic circuits.

    28. Asymmetric Organocatalysis

      Preparation of Chiral Amino Esters by Asymmetric Phase-Transfer Catalyzed Alkylations of Schiff Bases in a Ball Mill (pages 3773–3779)

      Pierrick Nun, Violaine Pérez, Monique Calmès, Jean Martinez and Frédéric Lamaty

      Version of Record online: 9 FEB 2012 | DOI: 10.1002/chem.201102885

      Thumbnail image of graphical abstract

      Grinding on one side! Ball milling under solvent-free conditions is presented herein for the synthesis of glycine Schiff bases and their subsequent asymmetric alkylation to prepare chiral natural and unnatural amino acids (see scheme). The use of a cinchona-derived catalyst provided good enantiomeric excesses up to 75 %.

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      Preview: Chem. Eur. J. 13/2012 (page 3783)

      Version of Record online: 13 MAR 2012 | DOI: 10.1002/chem.201290045

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