Chemistry - A European Journal

Cover image for Vol. 16 Issue 26

July 12, 2010

Volume 16, Issue 26

Pages 7649–7931

  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: 3D–2D–0D Stepwise Deconstruction of a Water Framework Templated by a Nanoporous Organic–Inorganic Hybrid Host (Chem. Eur. J. 26/2010) (page 7649)

      João Rocha, Fa-Nian Shi, Filipe A. Almeida Paz, Luís Mafra, Mariana Sardo, Luís Cunha-Silva, James Chisholm, Paulo Ribeiro-Claro and Tito Trindade

      Version of Record online: 5 JUL 2010 | DOI: 10.1002/chem.201090125

      Thumbnail image of graphical abstract

      Unprecedented 3D interpenetrated networks of hydrogen-bonded water molecules and a hybrid matrix have been found in a novel supramolecular salt, [H2pip]3[Ge(hedp)2]⋅14 H2O (H2pip2+=C4H12N22+; hedp5−=C2H3P2O75−). In their Full Paper on page 7741 ff., J. Rocha et al. demonstrate that this “ice framework” is stable at ambient temperature for long periods of time. The heating of this salt leads to a sequential framework deconstruction process, which occurs in a stepwise fashion from a 3D network into layers (2D) and, ultimately, discrete water aggregates (0D).

  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
    9. Preview
    1. Inside Cover: Preparation of Core–Shell-Structured Nanoparticles (with a Noble-Metal or Metal Oxide Core and a Chromia Shell) and Their Application in Water Splitting by Means of Visible Light (Chem. Eur. J. 26/2010) (page 7650)

      Kazuhiko Maeda, Naoyuki Sakamoto, Takahiro Ikeda, Hajime Ohtsuka, Anke Xiong, Daling Lu, Masayuki Kanehara, Toshiharu Teranishi and Kazunari Domen

      Version of Record online: 5 JUL 2010 | DOI: 10.1002/chem.201090126

      Thumbnail image of graphical abstract

      Photocatalytic overall water splitting using GaN:ZnO solid solution under visible light is promoted upon coating of nanoparticulate cocatalysts (metal or metal oxides) with a chromia shell, which suppresses undesirable reverse reactions, such as photoreduction of oxygen and water formation from hydrogen and oxygen on cocatalysts by inhibiting the access of oxygen molecules. For more details see the Full Paper by K. Domen et al. on page 7750 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
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  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. Reaction Mechanisms

      An Alternative Mechanistic Concept for Homogeneous Selective Ethylene Oligomerization of Chromium-Based Catalysts: Binuclear Metallacycles as a Reason for 1-Octene Selectivity? (pages 7670–7676)

      Stephan Peitz, Bhaskar R. Aluri, Normen Peulecke, Bernd H. Müller, Anina Wöhl, Wolfgang Müller, Mohammed H. Al-Hazmi, Fuad M. Mosa and Uwe Rosenthal

      Version of Record online: 22 JUN 2010 | DOI: 10.1002/chem.201000750

      Thumbnail image of graphical abstract

      2+2+2=6 and 2×4=8? This concept explains the differences of selectivity between ethylene tri- and tetramerization by the capability of the ligands to form binuclear complexes that subsequently build up two metallacyclopentanes in one moiety. These two C4 units are then coupled to form 1-octene selectively (see scheme).

  6. Communications

    1. Top of page
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    4. Graphical Abstract
    5. News
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    7. Communications
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    1. Natural Products

      Total Synthesis and Structural Revision of Biyouyanagin B (pages 7678–7682)

      K. C. Nicolaou, Silvano Sanchini, T. Robert Wu and David Sarlah

      Version of Record online: 22 JUN 2010 | DOI: 10.1002/chem.201001474

      Thumbnail image of graphical abstract

      An intriguing chase of the newly reported biyouyanagin B leads to its total synthesis and structural revision from 1′ to 1.

    2. Cascade Reactions

      Radical 1,2-O[RIGHTWARDS ARROW]C Transposition for Conversion of Phenols into Benzoates by O-Neophyl Rearrangement/Fragmentation Cascade (pages 7683–7687)

      Abdulkader Baroudi, Jeremiah Alicea and Igor V. Alabugin

      Version of Record online: 2 JUN 2010 | DOI: 10.1002/chem.201001056

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      Radical merry-go-round! Diaryl thiocarbonates, available in a single step from phenols, can be directly transformed into benzoates by a new radical cascade that transposes O and C atoms at the aromatic core. The cascade bypasses the common Barton–McCombie fragmentation in favor of the usually unfavorable O-neophyl rearrangement, which is rendered irreversible and efficient by a highly exothermic C[BOND]S bond scission in the O-centered radical (see scheme; FG=functional group).

    3. Benzylation

      Cobalt-Catalyzed Benzylzincation of Alkynes (pages 7688–7691)

      Kei Murakami, Hideki Yorimitsu and Koichiro Oshima

      Version of Record online: 2 JUN 2010 | DOI: 10.1002/chem.201001061

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      Carbometalation: Cobalt salts catalyze benzylzincation of alkynes to afford benzylated multisubstituted alkenes with high regio- and stereoselectivity. The scope of the reaction is wide enough to apply unfunctionalized alkynes as well as arylacetylenes. The reaction offers a new route to the regio- and stereoselective synthesis of an estrogen receptor antagonist (see scheme).

    4. Natural Products

      A Synthetic Entry into the Taiwaniaquinoids Based on a Biogenetic Hypothesis: Total Synthesis of (−)-Taiwaniaquinone H (pages 7692–7695)

      Chandan Kumar Jana, Rosario Scopelliti and Karl Gademann

      Version of Record online: 8 JUN 2010 | DOI: 10.1002/chem.201001085

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      Less carbon: Following a biogenetic proposal, the unusual 6-5-6 carbon skeleton of C19 taiwaniaquinoids was obtained by an intramolecular benzilic acid rearrangement from a C20 precursor. A protecting-group-free total synthesis then allowed for the preparation of (−)-taiwaniaquinone H (see scheme).

    5. Michael Addition

      Asymmetric Conjugate Addition of Nitromethane to Enones Catalyzed by Chiral N,N′-Dioxide–Scandium(III) Complexes (pages 7696–7699)

      Liwei Wang, Qi Zhang, Xin Zhou, Xiaohua Liu, Lili Lin, Bo Qin and Xiaoming Feng

      Version of Record online: 2 JUN 2010 | DOI: 10.1002/chem.201000688

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      Chalk it up as a “Sc”andal: The asymmetric conjugate addition of chalcone and “cinnamone” derivatives to nitromethane has been realized by using a simple and efficient scandium(III)–N,N′-dioxide complex as the catalyst (see scheme). In the presence of 2–5 mol % catalyst loading, the corresponding products were formed in excellent yields (up to 99 %) and enantioselectivities (up to>99 % ee).

    6. Molecular Devices

      Molecular Apparatus for Automatic Titrations (pages 7700–7703)

      Giuseppe Alibrandi, Carmelo Lo Vecchio, Antonino Villari and Iole Villari

      Version of Record online: 8 JUN 2010 | DOI: 10.1002/chem.201000965

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      Equipment free! A composite kinetic molecular device formed by a molecular titrator ([1.1.1]cryptand (A)) and a molecular pH meter (bromothymol blue (B)) was used as a substitute for the usual physical apparatus to perform an automatic spectrophotometric determination of the pKa of nimesulide (C). The confinement of the whole apparatus inside the spectrophotometric cuvette makes high-throughput pKa and stability determination in pharmaceutical analysis possible.

    7. Electrochemistry

      Ultrafast Synthesis of Layered Titanate Microspherulite Particles by Electrochemical Spark Discharge Spallation (pages 7704–7708)

      Yuxin Tang, Yuekun Lai, Dangguo Gong, Kok-Hui Goh, Teik-Thye Lim, Zhili Dong and Zhong Chen

      Version of Record online: 8 JUN 2010 | DOI: 10.1002/chem.201000330

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      Bright sparks! Hierarchical layered titanate microspherulite particles with large specific surface areas (406 m2 g−1) and excellent adsorption abilities were quickly synthesized by a facile method that simultaneously employed electrochemical anodization and spark discharge of the anodized oxide into a reactive solution (see figure).

    8. Organocatalysis

      Asymmetric Addition of Indoles to Isatins Catalysed by Bifunctional Modified Cinchona Alkaloid Catalysts (pages 7709–7713)

      Pankaj Chauhan and Swapandeep Singh Chimni

      Version of Record online: 8 JUN 2010 | DOI: 10.1002/chem.201000846

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      Simple and selective: An efficient organocatalytic enantioselective method for the synthesis of substituted-3-hydroxyoxindole derivatives with a quaternary chiral carbon has been developed. The cinchona alkaloid derived catalyst catalyses the Friedel–Crafts-type addition of indole derivatives to the isatin derivatives under mild conditions to provide substituted 3-hydroxyoxindoles in good to excellent yields with high enantioselectivity (see scheme).

    9. Asymmetric Organocatalysis

      Organocatalytic Asymmetric Cyanosilylation of Nitroalkenes (pages 7714–7718)

      Pablo Bernal, Rosario Fernández and José M. Lassaletta

      Version of Record online: 8 JUN 2010 | DOI: 10.1002/chem.201001107

      Thumbnail image of graphical abstract

      New catalyst, new reaction: The unprecedented cyanosilylation of nitroalkenes can be efficiently catalyzed by a bifunctional quinine derivative with tetraalkylammonium cyanide and thiourea moieties. The activation of the nitroalkene by hydrogen bonding to the thiourea, together with the presence of an “active” cyanide, provides a new mode of activation that leads to products in high yields and good selectivities (see scheme).

    10. Molecular Devices

      A Self-Powered and Reusable Biocomputing Security Keypad Lock System Based on Biofuel Cells (pages 7719–7724)

      Ming Zhou, Xiliang Zheng, Jin Wang and Shaojun Dong

      Version of Record online: 28 MAY 2010 | DOI: 10.1002/chem.201000619

      Thumbnail image of graphical abstract

      Locked up! A novel self-powered, reusable biofuel cell (BFC) based biocomputing security system mimicking a keypad lock device using enzyme-based concatenated AND logic gates has been developed (see figure; FFD=fructan beta-fructosidase, INV=invertase, GOD=glucose oxidase, URE=urease).

    11. Gold-Catalyzed Synthesis

      Gold(I)-Catalyzed Domino Reaction of Aziridinyl Alkynes (pages 7725–7729)

      Zhen Zhang and Min Shi

      Version of Record online: 8 JUN 2010 | DOI: 10.1002/chem.201000628

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      Aziridinyl alkynes strike gold: A novel gold(I)-catalyzed domino transformation of aziridinyl alkynes with arenes to construct 1,2,3,4-tetrahydroisoquinoline and 3,4-dihydroisoquinoline structural motifs (see scheme), especially sterically congested syn-3,4-disubstituted 1,2,3,4-tetrahydroisoquinolines, is described. A plausible mechanism proceeding through a benzylic cation is given based upon deuterium-labeling and control experiments as well as the observed diastereoselectivities.

  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. Biomimetic Materials

      Hierarchical, Titania-Coated, Carbon Nanofibrous Material Derived from a Natural Cellulosic Substance (pages 7730–7740)

      Xiaoyan Liu, Yuanqing Gu and Jianguo Huang

      Version of Record online: 16 JUN 2010 | DOI: 10.1002/chem.201000436

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      Gift from nature: A hierarchical titania–carbon hybrid material composed of porous carbon nanofibers coated with a uniform anatase titania film (see figure) was fabricated by using a natural cellulosic substance (filter paper) as both a scaffold and carbon precursor. The material possesses enhanced photocatalytic degradation efficiency with respect to different dyes and improved photoreduction performance of silver cations to silver nanoparticles.

    2. Water Chemistry

      3D–2D–0D Stepwise Deconstruction of a Water Framework Templated by a Nanoporous Organic–Inorganic Hybrid Host (pages 7741–7749)

      João Rocha, Fa-Nian Shi, Filipe A. Almeida Paz, Luís Mafra, Mariana Sardo, Luís Cunha-Silva, James Chisholm, Paulo Ribeiro-Claro and Tito Trindade

      Version of Record online: 11 JUN 2010 | DOI: 10.1002/chem.201000431

      Thumbnail image of graphical abstract

      Ice framework deconstruction: The supramolecular salt [H2pip]3[Ge(hedp)2]⋅14 H2O (pip=C4H12N22+; hedp=C2H3P2O75−) features 3D interpenetrated networks of hydrogen-bonded water molecules and a hybrid matrix (see figure). The ‘ice’ framework is stable up to around 22 °C, and its deconstruction occurs in a stepwise fashion from 3D to 2D and discrete water aggregates (0D). In the process, however, the long-range order of the hybrid host is preserved.

    3. Water Splitting

      Preparation of Core–Shell-Structured Nanoparticles (with a Noble-Metal or Metal Oxide Core and a Chromia Shell) and Their Application in Water Splitting by Means of Visible Light (pages 7750–7759)

      Kazuhiko Maeda, Naoyuki Sakamoto, Takahiro Ikeda, Hajime Ohtsuka, Anke Xiong, Daling Lu, Masayuki Kanehara, Toshiharu Teranishi and Kazunari Domen

      Version of Record online: 16 JUN 2010 | DOI: 10.1002/chem.201000616

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      Breaking up is hard to do: Photodeposition of chromia onto nanoparticulate co-catalysts (metals or metal oxides) onto a GaN:ZnO solid solution to form a core–shell configuration resulted in enhanced activity for photocatalytic overall water splitting under visible light (see figure).

    4. Spiro Compounds

      Formation of a leuco Spirolactone from 4-(2-Carboxyphenyl)-7-diethylamino-4′-dimethylamino-1-benzopyrylium: Design of a Phase-Change Thermochromic System Based on a Flavylium Dye (pages 7760–7766)

      Raquel Gavara, César A. T. Laia, A. Jorge Parola and Fernando Pina

      Version of Record online: 27 MAY 2010 | DOI: 10.1002/chem.200903482

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      A new phase-change thermochromic system is described (see scheme), which is based on the 4-(2-carboxyphenyl)-7-diethylamino-4-dimethylamino-1-benzopyrylium dye and its leuco form, a spirolactone.

    5. Annulenes

      Singly and Doubly Twisted [36]Annulenes: Synthesis and Calculations (pages 7767–7772)

      Ali Reza Mohebbi, Eva-Katrin Mucke, Gaston R. Schaller, Felix Köhler, Frank D. Sönnichsen, Ludger Ernst, Christian Näther and Rainer Herges

      Version of Record online: 27 MAY 2010 | DOI: 10.1002/chem.201000277

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      Do the twist! Möbius and Hückel conformations (single- and double-twisted) were crystallized from a solution of a cyclophane with a [36]annulene periphery in different solvents (see figure). All new structures were clearly identified by X-ray analysis and confirmed by DFT calculations. An energetically favorable triple-twisted conformation of the annulene was also located by using DFT calculations.

    6. Acylation

      Selective Monoacylation of Ferrocene with Bulky Acylating Agents over Mesoporous Sieve AlKIT-5 (pages 7773–7780)

      Dana Procházková, Martina Bejblová, Josef Vlk, Ajayan Vinu, Petr Štěpnička and Jiří Čejka

      Version of Record online: 2 JUN 2010 | DOI: 10.1002/chem.201000218

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      A hole-istic solution: AlKIT-5 mesoporous molecular sieves, which are readily prepared by direct template synthesis with varying Al/Si ratios, proved to be efficient, selective, and recyclable catalysts for selective monoacylation of ferrocene with bulky acylation agents (see image).

    7. siRNA/PAMAM Interactions

      PAMAM Dendrimers for siRNA Delivery: Computational and Experimental Insights (pages 7781–7795)

      Giovanni Maria Pavan, Paola Posocco, Aaron Tagliabue, Marek Maly, Anastasia Malek, Andrea Danani, Enzio Ragg, Carlo V. Catapano and Sabrina Pricl

      Version of Record online: 21 MAY 2010 | DOI: 10.1002/chem.200903258

      Thumbnail image of graphical abstract

      Snapshots taken from molecular dynamics simulations of PAMAM generations G6 in a complex with GL3 siRNA at pH 7.4 are shown here. Dendrimers are depicted as colored sticks, the terminal NH3+ groups as white balls and sticks. The siRNA is outlined as a golden ribbon. Sodium and chlorine counterions are portrayed as purple and green spheres, respectively. Water is omitted for clarity.

    8. Self-Assembly

      Guest⊂Guest⊂Host Multicomponent Molecular Crystals: Entrapment of Guest⊂Guest in Honeycomb Networks Formed by Self-Assembly of 1,3,5-Tri(4-hydroxyaryl)benzenes (pages 7796–7802)

      Jarugu Narasimha Moorthy and Palani Natarajan

      Version of Record online: 21 MAY 2010 | DOI: 10.1002/chem.200902816

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      A sterically-engineered rigid trigonal triphenol undergoes O–H⋅⋅⋅O hydrogen-bonded self-assembly in the presence of [18]crown-6 and neutral (MeOH/water, MeOH/MeNO2) or ionic guest species (KI/KAcAc) to furnish novel multicomponent assemblies, that is, guestguesthost, which typify Russian dolls.

    9. Receptor–Ligand Interactiond

      Ligand–Receptor Binding Affinities from Saturation Transfer Difference (STD) NMR Spectroscopy: The Binding Isotherm of STD Initial Growth Rates (pages 7803–7812)

      Jesús Angulo, Pedro M. Enríquez-Navas and Pedro M. Nieto

      Version of Record online: 21 MAY 2010 | DOI: 10.1002/chem.200903528

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      The initial growth rates of the STD amplification factors cancel out spurious experimental factors due to protein–ligand rebinding, which affects the accumulation of saturation in the free ligand and allows accurate determinations of dissociation constants (KD) from the variation of STD NMR spectroscopy values with the receptor–ligand ratio (BSA=bovine serum albumin, see figure).

    10. Cavitand Receptors

      Ion-Pair Complexation with a Cavitand Receptor (pages 7813–7819)

      Francesca Tancini, Thomas Gottschalk, W. Bernd Schweizer, François Diederich and Enrico Dalcanale

      Version of Record online: 10 JUN 2010 | DOI: 10.1002/chem.201000573

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      Phosphotriester cavitand: The lower rim pocket of a methylene-bridged cavitand, preorganized for anion binding, has been decorated with four phosphotriester residues at the termini of the feet for counterion complexation by hydrogen bonding (see figure). The combination of the two modes of interaction leads to the efficient binding of primary ammonium salts in the form of ion pairs.

    11. Electron Transfer

      Inter- and Intramolecular Photoinduced Electron Transfer of Flavin Derivatives with Extremely Small Reorganization Energies (pages 7820–7832)

      Motonobu Murakami, Kei Ohkubo and Shunichi Fukuzumi

      Version of Record online: 21 MAY 2010 | DOI: 10.1002/chem.200903236

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      Long-lived charge separation: 10-[4′-(N,N-Dimethylamino)phenyl]–isoalloxazine (DMA–Fl) undergoes efficient intramolecular photoinduced electron transfer to afford the charge-separated (CS) state that has the longest CS lifetime (2.1 ms) by preventing the intermolecular back electron transfer in solution at 298 K (see figure).

    12. Homogeneous Catalysis

      Influence of Process Parameters on the Reaction Kinetics of the Chromium-Catalyzed Trimerization of Ethylene (pages 7833–7842)

      Anina Wöhl, Wolfgang Müller, Stephan Peitz, Normen Peulecke, Bhaskar R. Aluri, Bernd H. Müller, Detlef Heller, Uwe Rosenthal, Mohammed H. Al-Hazmi and Fuad M. Mosa

      Version of Record online: 28 MAY 2010 | DOI: 10.1002/chem.201000533

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      Finding the parameters: An extensive experimental parameter study has been carried out on a novel ethylene trimerization catalyst system. Ethylene and catalyst concentration were found to affect the initial activity, and the activation energy (Ea) was determined by studying temperature dependencies (see figure).

    13. Aromaticity

      Demonstration of “Möbius” Aromaticity in Planar Metallacycles (pages 7843–7851)

      Michael Mauksch and Svetlana B. Tsogoeva

      Version of Record online: 21 MAY 2010 | DOI: 10.1002/chem.201000396

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      Without a twist: Several seven- and eight-membered metallacycles that contain transition-metal atoms with available d orbitals of appropriate symmetry and orientation are computationally demonstrated to be “Möbius” aromatic with eight electrons involved in the cyclic delocalization (see figure).

    14. Nanostructures

      Chirally Functionalized Hollow Nanospheres Containing L-Prolinamide: Synthesis and Asymmetric Catalysis (pages 7852–7858)

      Jinsuo Gao, Jian Liu, Jianting Tang, Dongmei Jiang, Bo Li and Qihua Yang

      Version of Record online: 27 MAY 2010 | DOI: 10.1002/chem.201000161

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      Hollowed be thy name: L-Prolinamide-functionalized hollow nanospheres with different surface hydrophobicity/hydrophilicity were prepared. The catalytic activity of the hollow nanospheres was clearly improved after framework and surface hydrophobic decoration (see graphic; TOF=turnover frequency) for an asymmetric aldol reaction in the presence of water.

    15. Chirality-Sensing Polymer

      Chirality-Sensing Binaphthocrown Ether–Polythiophene Conjugate (pages 7859–7864)

      Gaku Fukuhara and Yoshihisa Inoue

      Version of Record online: 20 MAY 2010 | DOI: 10.1002/chem.200903545

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      In a twist: Upon inclusion of a chiral cationic guest in the cavity of a newly synthesized chiral crown ether–polythiophene conjugate, the bithiophene unit was twisted to shorten the effective conjugation length of the polythiophene backbone, enabling us to sense the guest binding by reading out the amplified optical signal gains arising from the backbone structure change (see figure).

    16. Photocatalysis

      Fabrication of Large-Scale Hierarchical ZnO Hollow Spheroids for Hydrophobicity and Photocatalysis (pages 7865–7874)

      Arun Kumar Sinha, Mrinmoyee Basu, Mukul Pradhan, Sougata Sarkar and Tarasankar Pal

      Version of Record online: 21 MAY 2010 | DOI: 10.1002/chem.200903347

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      Cocoonlike structures: A simple procedure allows the preparation of a hollow spheroid ZnO material like a natural cocoon (see figure). A bubble-template strategy is designed through a modified hydrothermolysis (MHT) reaction to construct hollow ZnO nanostructures. The hollow spheroids allow multiple reflections of UV-visible light within the interior cavity that facilitates efficient usage of the light source. The 3D nanococoon architecture improves the superhydrophobicity and photocatalytic performances of these materials.

    17. Organocatalysis

      Organocatalyzed Cyclopropanation of α-Substituted α,β-Unsaturated Aldehydes: Enantioselective Synthesis of Cyclopropanes Bearing a Chiral Quaternary Center (pages 7875–7880)

      Vincent Terrasson, Arie van der Lee, Renata Marcia de Figueiredo and Jean Marc Campagne

      Version of Record online: 28 MAY 2010 | DOI: 10.1002/chem.201000334

      Thumbnail image of graphical abstract

      Enantioselective cyclopropanation of α-substituted α,β-unsaturated aldehydes is reported (see scheme). The transformation is driven by diphenylprolinol trimethylsilyl ether. A variety of cyclopropanes bearing a chiral quaternary stereocenter at the α-position of the aldehydes is obtained.

    18. Amyloid Formation

      How Post-Translational Modifications Influence Amyloid Formation: A Systematic Study of Phosphorylation and Glycosylation in Model Peptides (pages 7881–7888)

      Malgorzata Broncel, Jessica A. Falenski, Sara C. Wagner, Christian P. R. Hackenberger and Beate Koksch

      Version of Record online: 20 MAY 2010 | DOI: 10.1002/chem.200902452

      Thumbnail image of graphical abstract

      All against amyloid formation: An important step towards the understanding of the impact of phosphorylation and glycosylation on amyloid formation has been made (see figure). It has been demonstrated that even single phosphorylation is sufficient to completely inhibit fibrilization, whereas glycosylation showed more diverse effects.

    19. Homogeneous Catalysis

      Selective and Efficient Cycloisomerization of Alkynols Catalyzed by a New Ruthenium Complex with a Tetradentate Nitrogen–Phosphorus Mixed Ligand (pages 7889–7897)

      Pei Nian Liu, Fu Hai Su, Ting Bin Wen, Herman H.-Y. Sung, Ian D. Williams and Guochen Jia

      Version of Record online: 2 JUN 2010 | DOI: 10.1002/chem.200903441

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      Go complex! The new air-stable ruthenium complex 1 is an effective catalyst for the endo cycloisomerization of a range of alkynols to give exclusively endo-cyclic enol ethers of five-, six-, and seven-membered rings in high yields under nonbasic conditions (see scheme). The catalytic reactions can be carried out with a low loading of catalyst without additional co-catalyst.

    20. Membranes

      Hydrogen Production by Water Dissociation in Surface-Modified BaCoxFeyZr1−xyO3−δ Hollow-Fiber Membrane Reactor with Improved Oxygen Permeation (pages 7898–7903)

      Heqing Jiang, Fangyi Liang, Oliver Czuprat, Konstantin Efimov, Armin Feldhoff, Steffen Schirrmeister, Thomas Schiestel, Haihui Wang and Jürgen Caro

      Version of Record online: 21 MAY 2010 | DOI: 10.1002/chem.200902494

      Thumbnail image of graphical abstract

      Go with the flow: Perovskite BaCoxFeyZr1−xyO3−δ (BCFZ) oxygen permeable membranes were used as reactors to shift the equilibrium of water dissociation for hydrogen production. The hydrogen production rate was increased from 0.7 to 2.1 mL min−1 cm−2 at 950 °C after depositing a BCFZ-Pd porous layer onto the BCFZ hollow-fiber membrane (see figure).

    21. Multicomponent Reactions

      Boron-Based Dipolar Multicomponent Reactions: Simple Generation of Substituted Aziridines, Oxazolidines and Pyrrolidines (pages 7904–7915)

      Nicola Kielland, Federica Catti, Davide Bello, Nicolas Isambert, Ignacio Soteras, F. Javier Luque and Rodolfo Lavilla

      Version of Record online: 27 MAY 2010 | DOI: 10.1002/chem.201000349

      Thumbnail image of graphical abstract

      One step, four components: An early report from the 1960s has been reformulated into a novel family of multicomponent reactions that leads to aziridine, oxazolidine and pyrrolidine scaffolds just by mixing the reactants (see picture). The scope and mechanistic course of these domino processes are determined. Solid-phase protocols allow straightforward preparations and even permit chemo-differentiation of pseudo-equivalent inputs.

      Corrected by:

      Corrigendum: Corrigendum: Boron-Based Dipolar Multicomponent Reactions: Simple Generation of Substituted Aziridines, Oxazolidines and Pyrrolidines

      Vol. 17, Issue 45, 12537, Version of Record online: 25 OCT 2011

    22. Phosphide Nanowires

      Phase-Controlled Synthesis of Transition-Metal Phosphide Nanowires by Ullmann-Type Reactions (pages 7916–7924)

      Junli Wang, Qing Yang, Zude Zhang and Shouheng Sun

      Version of Record online: 20 MAY 2010 | DOI: 10.1002/chem.200902151

      Thumbnail image of graphical abstract

      Transition metals react with PPh3 in vacuum-sealed tubes at 350–400 °C to form metal phosphide nanowires by Ullmann-type reactions involving phenyl radicals (see general equation, superimposed on a TEM image of Co2P nanowires). The phase (stoichiometry) of the phosphide nanostructures can be controlled by means of the metal/PPh3 molar ratio and concentration, reaction temperature and time, and heating rate, and they exhibit interesting phase- and composition-dependent magnetic properties.

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      Version of Record online: 5 JUL 2010 | DOI: 10.1002/chem.201090129

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