Angewandte Chemie International Edition

Cover image for Vol. 48 Issue 5

January 19, 2009

Volume 48, Issue 5

Pages 829–991

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Cover Picture: Biomolecular Nanopatterning by Magnetic Electric Lithography (Angew. Chem. Int. Ed. 5/2009) (page 829)

      Zhen Gu, Suxian Huang and Yong Chen

      Article first published online: 13 JAN 2009 | DOI: 10.1002/anie.200990006

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      Biomolecular nanopatterns can be quickly fabricated over a large area with a resolution down to 10 nm by magnetic electric lithography, as reported by Z. Gu, S. Huang, and Y. Chen in their Communication on page 952 ff. Magnetic nanoparticles coated with multiple distinct biomolecules are deposited by a magnetic field and immobilized onto nanoelectrodes by an electric field to generate arbitrary heterogeneous biomolecular nanopatterns, which can then be printed onto polymer films for diverse biomedical applications.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Inside Cover: Weakly Coordinating Cations as Alternatives to Weakly Coordinating Anions (Angew. Chem. Int. Ed. 5/2009) (page 830)

      Craig J. Price, Hsuan-Ying Chen, L. Marie Launer and Stephen A. Miller

      Article first published online: 13 JAN 2009 | DOI: 10.1002/anie.200990007

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      A deserted island illustrates the weakly coordinating nature of a sterically shielded cation, as described by S. A. Miller and co-workers in their Communication on page 956 ff. Such sterically encumbered cations offer a strategy complementary to that of weakly coordinating anions for diminishing cation–anion interactions. The steric differences are reflected in the absorption maxima of the complexes, which in turn can be detected by the naked eye (green vs. purple).

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Graphical Abstract: Angew. Chem. Int. Ed. 5/2009 (pages 833–841)

      Article first published online: 13 JAN 2009 | DOI: 10.1002/anie.200990008

  4. News

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
    12. Preview
  5. Author Profile

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Christopher C. Cummins (page 845)

      Article first published online: 13 JAN 2009 | DOI: 10.1002/anie.200990010

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  6. Book Reviews

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
    12. Preview
  7. Highlights

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Asymmetric Catalysis

      Exceptional Selectivity in Cyclopropanation Reactions Catalyzed by Chiral Cobalt(II)–Porphyrin Catalysts (pages 850–852)

      Michael P. Doyle

      Article first published online: 30 DEC 2008 | DOI: 10.1002/anie.200804940

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      Toss the olefin into the porphyrin: The development of chiral cobalt(II)–porphyrin catalysts by straightforward coupling processes has made possible the additions of diazocarbonyl compounds to a broad spectrum of olefins to access functionalized cylopropanes. The cyclopropanation reactions demonstrate high product yields, exceptional diastereoselectivity, and excellent enantiocontrol.

    2. MicroRNA

      MicroRNAs Repress Mainly through mRNA Decay (pages 853–855)

      Stephanie Esslinger and Klaus Förstemann

      Article first published online: 29 DEC 2008 | DOI: 10.1002/anie.200805127

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      Inhibition or degradation? MicroRNAs have been considered primarily as inhibitors of translation, even though degradation of mRNAs also plays a role in their repressive potential. Two research groups have now quantified the extent to which each mechanism contributes to gene regulation by combining mass spectrometry with transcriptome profiling. The surprising conclusion is that translational inhibition plays only a minor role!

  8. Minireview

    1. Top of page
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    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Bioanalysis

      Molecular Engineering of DNA: Molecular Beacons (pages 856–870)

      Kemin Wang, Zhiwen Tang, Chaoyong James Yang, Youngmi Kim, Xiaohong Fang, Wei Li, Yanrong Wu, Colin D. Medley, Zehui Cao, Jun Li, Patrick Colon, Hui Lin and Weihong Tan

      Article first published online: 9 DEC 2008 | DOI: 10.1002/anie.200800370

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      A spotlight on light signaling: Molecular beacons are specifically designed DNA hairpin structures (see picture) used as fluorescent probes for numerous bioanalytical applications, including gene detection, the monitoring of messenger RNA (mRNA), and biosensing. Recent studies have led to versatile strategies for the targeted optimization of molecular beacons. ssDNA=single-stranded DNA.

  9. Review

    1. Top of page
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    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Diagnostics and Drug Delivery

      Nanomedicine—Challenge and Perspectives (pages 872–897)

      Kristina Riehemann, Stefan W. Schneider, Thomas A. Luger, Biana Godin, Mauro Ferrari and Harald Fuchs

      Article first published online: 13 JAN 2009 | DOI: 10.1002/anie.200802585

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      Future of nanomedicine: Multiple functions can be integrated into nanoparticle systems for drug delivery. The schematic representation of a third-generation nanovector illustrates this: On the outside are recognition units to interact with target cells and biological barriers, while inside are drug-loaded nanoparticles, which leave the vector at the correct moment and release their load.

  10. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
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    1. Gas-Phase Reactions

      Interactions of Small Protected Peptides with Aminopyrazole Derivatives: The Efficiency of Blocking a β-Sheet Model in the Gas Phase (pages 900–904)

      Holger Fricke, Andreas Gerlach, Claus Unterberg, Mark Wehner, Thomas Schrader and Markus Gerhards

      Article first published online: 30 DEC 2008 | DOI: 10.1002/anie.200802396

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      Binding motifs of aminopyrazole derivatives with different peptides in the gas phase are investigated by using mass- and isomer-selective IR/UV spectroscopy. The efficiency of blocking a β-sheet model is determined by analyzing the number and strength of hydrogen bonds (see picture). The investigations yield information on intrinsic molecular properties of beginning aggregation behavior, as might also occur in misfolding diseases.

    2. Ammonia–Borane Dehydrogenation

      Ruthenium Complexes with Cooperative PNP Ligands: Bifunctional Catalysts for the Dehydrogenation of Ammonia–Borane (pages 905–907)

      Martina Käß, Anja Friedrich, Markus Drees and Sven Schneider

      Article first published online: 30 DEC 2008 | DOI: 10.1002/anie.200805108

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      G“Ru”vy reactivity: The new ruthenium(II) complex having cooperative PNP enamido ligand A reversibly activates two equivalents H2 under reversible hydrogenation of amido (B) and amino (C) complexes. B exhibits the highest reported activities in the dehydrocoupling of ammonia–borane.

    3. Asymmetric Synthesis

      Asymmetric Brønsted Acid Catalysis: Catalytic Enantioselective Synthesis of Highly Biologically Active Dihydroquinazolinones (pages 908–910)

      Magnus Rueping, Andrey P. Antonchick, Erli Sugiono and Konstantin Grenader

      Article first published online: 19 DEC 2008 | DOI: 10.1002/anie.200804770

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      Surprisingly straightforward: A metal-free, highly enantioselective Brønsted acid catalyzed condensation/addition reaction has been developed for the construction of 2,3-dihydroquinazolinones starting from 2-aminobenzamide and aldehydes (see scheme). This efficient approach provides 2,3-dihydroquinazolinones with a strong preference for the S enantiomers, which have higher biological activities than the R enantiomers.

    4. Azaanthracenones

      Total Syntheses of Cytotoxic, Naturally Occurring Kalasinamide, Geovanine, and Marcanine A (pages 911–913)

      Steffen Lang and Ulrich Groth

      Article first published online: 29 DEC 2008 | DOI: 10.1002/anie.200804388

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      Two novel synthetic strategies were developed for the natural products geovanine, marcanine A, and kalasinamide. The nine-step synthesis of geovanine marks its first total synthesis. The three compounds are known for their antimalarial and antitumor activity, and tests confirmed the high cytotoxity of marcanine A.

    5. Natural Products

      Structure Determination and Total Synthesis of Bottromycin A2: A Potent Antibiotic against MRSA and VRE (pages 914–917)

      Hiroyuki Shimamura, Hiroaki Gouda, Kenichiro Nagai, Tomoyasu Hirose, Maki Ichioka, Yujiro Furuya, Yutaka Kobayashi, Shuichi Hirono, Toshiaki Sunazuka and Satoshi Ōmura

      Article first published online: 29 DEC 2008 | DOI: 10.1002/anie.200804138

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      After 50 years of persistence the 12-membered cyclic skeleton of bottromycin A2 (3) has been confirmed by NMR experiments (HMBC), and the configurations of two tLeu residues have been estimated by conformation analysis and NMR experiments. Furthermore, the key step in the synthesis of 3 involves the mercury-mediated formation of the amidine of thioamide 1 and amine 2.

    6. Synthetic Methods

      Practical Imidazole-Based Phosphine Ligands for Selective Palladium-Catalyzed Hydroxylation of Aryl Halides (pages 918–921)

      Thomas Schulz, Christian Torborg, Benjamin Schäffner, Jun Huang, Alexander Zapf, Renat Kadyrov, Armin Börner and Matthias Beller

      Article first published online: 22 DEC 2008 | DOI: 10.1002/anie.200804898

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      The phenol countdown: Novel imidazole-based phosphine ligands are synthesized on scales up to 100 g by a convenient lithiation–phosphorylation method. The phosphines are stable towards air and moisture and are successfully applied as ligands in the palladium-catalyzed selective hydroxylation of aryl halides (see scheme, dba=dibenzylideneacetone).

    7. Catalytic Foldamers

      A Rationally Designed Aldolase Foldamer (pages 922–925)

      Manuel M. Müller, Matthew A. Windsor, William C. Pomerantz, Samuel H. Gellman and Donald Hilvert

      Article first published online: 17 DEC 2008 | DOI: 10.1002/anie.200804996

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      Neatly folded: A decameric β-peptide shows enzyme-like catalytic properties. The foldamer, which bears a terminal heptanoyl unit and displays a thermostable helical structure with an array of ammonium-group side chains, accelerates a retroaldol reaction (see scheme) by more than three orders of magnitude through an imine mechanism.

    8. Self-Assembly

      Economical Design in Noncovalent Nanoscale Synthesis: Diverse Photofunctional Nanostructures Based on a Single Covalent Building Block (pages 926–930)

      Galina Golubkov, Haim Weissman, Elijah Shirman, Sharon G. Wolf, Iddo Pinkas and Boris Rybtchinski

      Article first published online: 7 JAN 2009 | DOI: 10.1002/anie.200805202

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      Four from one: Nanoscale ribbons, tubes, vesicles, and platelets can be formed from the self-assembly of a single covalent unit, which is based on an amphiphilic perylene diimide functionalized with a terpyridine ligand (see picture). The assembly diversity arises from the encoding of multiple inputs through hydrophobic interactions and metal coordination.

    9. Homogeneous Catalysis

      Highly Active Dizinc Catalyst for the Copolymerization of Carbon Dioxide and Cyclohexene Oxide at One Atmosphere Pressure (pages 931–933)

      Michael R. Kember, Paul D. Knight, Palarp T. R. Reung and Charlotte K. Williams

      Article first published online: 29 DEC 2008 | DOI: 10.1002/anie.200803896

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      Low-pressure catalyst: A novel dizinc complex (1) having a macrocyclic ancillary ligand shows remarkable activity for the copolymerization of carbon dioxide and cyclohexene oxide, at only one atmosphere of CO2. TON=turnover number; TOF=turnover frequency.

    10. Phosphorus Chemistry

      Tetraphosphabenzenes Obtained via a Triphosphacyclobutadiene Intermediate (pages 934–938)

      Nicholas A. Piro and Christopher C. Cummins

      Article first published online: 19 DEC 2008 | DOI: 10.1002/anie.200804432

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      An acyl triphosphirene ligand transfers an O atom to Nb to liberate the putative triphosphacyclobutadiene intermediate [RCP3{W(CO)5}2], which engages in [2+4]-cycloaddition reactions with an organic diene and a phosphaalkyne (see scheme; P orange, O red, W violet, C white). The latter reaction yields the Dewar isomer of a tetraphosphabenzene, which can be converted to a tetraphosphabenzvalene containing a Z-diphosphene.

    11. Nanocrystal Separation

      Separation of Nanoparticles in a Density Gradient: FeCo@C and Gold Nanocrystals (pages 939–942)

      Xiaoming Sun, Scott M. Tabakman, Won-Seok Seo, Li Zhang, Guangyu Zhang, Sarah Sherlock, Lu Bai and Hongjie Dai

      Article first published online: 23 DEC 2008 | DOI: 10.1002/anie.200805047

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      The right sort: A post-synthesis, liquid-phase separation method sorts nanoparticles by centrifugation in a medium with a density gradient. The particles are sorted according to particle size, clustering degree, and core density ρ (see picture; d=sedimentation distance). Solid–solid interactions between colloidal particles and stable phases are thus avoided. This versatile method allows for determination of the colloid size distribution in a suspension.

    12. Photonic Crystals

      Electroactive Inverse Opal: A Single Material for All Colors (pages 943–947)

      Daniel P. Puzzo, Andre C. Arsenault, Ian Manners and Geoffrey A. Ozin

      Article first published online: 3 DEC 2008 | DOI: 10.1002/anie.200804391

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      I see the light: When an electroactive inverse polymer-gel opal is electrochemically oxidized and reduced, the lattice swells and shrinks, respectively. Concomitantly the wavelength of brightly diffracted light can be altered all the way from the ultraviolet through the visible to the near infrared (see picture).

    13. Antimicrobial Agents

      Multivalent Choline Dendrimers as Potent Inhibitors of Pneumococcal Cell-Wall Hydrolysis (pages 948–951)

      Víctor M. Hernández-Rocamora, Beatriz Maestro, Bas de Waal, María Morales, Pedro García, E. W. Meijer, Maarten Merkx and Jesús M. Sanz

      Article first published online: 29 DEC 2008 | DOI: 10.1002/anie.200803664

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      Dendritic cell-wall mimics: Choline-binding proteins from Streptococcus pneumoniae recognize distinctive multivalent choline architectures on the bacterial cell wall. Choline-functionalized dendrimers are potent inhibitors of these essential enzymes, with a 103–104-fold higher affinity than free choline, resulting in inhibition of autolysis and cell separation in bacterial cultures at low micromolar concentrations (see picture).

    14. Biomolecular Nanopatterning

      Biomolecular Nanopatterning by Magnetic Electric Lithography (pages 952–955)

      Zhen Gu, Suxian Huang and Yong Chen

      Article first published online: 12 NOV 2008 | DOI: 10.1002/anie.200803456

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      Paint by number? Magnetic nanoparticles (MNPs) coated with distinct biomolecules (see picture) can be assembled onto nanoelectrodes on a template under the control of magnetic and electric fields. The MNP–biomolecule conjugates can then be transferred from the template to a biocompatible polymer substrate. Arbitrary nanopatterns can be fabricated by the magnetic electric lithography process over a large area with a resolution down to 10 nm.

    15. Cation–Anion Interactions

      Weakly Coordinating Cations as Alternatives to Weakly Coordinating Anions (pages 956–959)

      Craig J. Price, Hsuan-Ying Chen, L. Marie Launer and Stephen A. Miller

      Article first published online: 26 NOV 2008 | DOI: 10.1002/anie.200802605

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      Big is beautiful: Activation of fluorenyl-based zirconocenes with methylaluminoxane (MAO) effects a red shift in the visible λmax proportional to the size of the metallocene (see potential energy surfaces in picture). Polymerization activities correlate directly with color (λmax), suggesting that bulky zirconocenium catalysts are weakly coordinating cations which, like weakly coordinating anions, diminish cation–anion interactions.

    16. Duplex Structures

      Insight into the High Duplex Stability of the Simplified Nucleic Acid GNA (pages 960–963)

      Mark K. Schlegel, Xiulan Xie, Lilu Zhang and Eric Meggers

      Article first published online: 7 JAN 2009 | DOI: 10.1002/anie.200803472

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      A preorganized zipper: The entropic penalty for duplex formation is significantly smaller for the backbone-simplified nucleic acid analogue GNA (glycol nucleic acid) than for DNA. This finding is consistent with a conformational preorganization of the single strands in combination with especially favorable stacking interactions in the corresponding GNA duplex (see picture).

    17. Supramolecular Chemistry

      Polymeric Core–Shell Assemblies Mediated by Host–Guest Interactions: Versatile Nanocarriers for Drug Delivery (pages 964–968)

      Jianxiang Zhang and Peter X. Ma

      Article first published online: 19 DEC 2008 | DOI: 10.1002/anie.200804135

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      First class delivery: Core–shell structured nanoassemblies could be constructed from a hydrophilic–hydrophilic block copolymer with one block containing β-cyclodextrin in the presence of hydrophobic guest compounds (see picture). The polymer can host various guest molecules, while the difference in sensitivity can be utilized to regulate release rate. By selecting appropriate guests, polyion complex (PIC) micelles could also be assembled.

    18. Photoinduced Drug Release

      Magnetically Guided Titania Nanotubes for Site-Selective Photocatalysis and Drug Release (pages 969–972)

      Nabeen K. Shrestha, Jan M. Macak, Felix Schmidt-Stein, Robert Hahn, Claudia T. Mierke, Ben Fabry and Patrik Schmuki

      Article first published online: 29 DEC 2008 | DOI: 10.1002/anie.200804429

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      Quick release: The spatial and temporal delivery of active molecules (dyes or drugs) can be precisely controlled by the photocatalytic activity of TiO2 nanotubes (see picture). The cleavage of the link between the active molecule and the nanotubes, which are filled with magnetic Fe3O4 nanoparticles, occurs by photoinduced chain scission under UV light; the load can be released before photodegradation by action of photogenerated radicals can occur.

    19. Boron Heterocycles

      A Hybrid Organic/Inorganic Benzene (pages 973–977)

      Adam J. V. Marwitz, Myrna H. Matus, Lev N. Zakharov, David A. Dixon and Shih-Yuan Liu

      Article first published online: 22 DEC 2008 | DOI: 10.1002/anie.200805554

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      It isn't easy BN aromatic! 1,2-Dihydro-1,2-azaborine, a hybrid organic/inorganic benzene, is a stable aromatic molecule with features that are distinct from its isoelectronic “organic” (benzene) and “inorganic” (borazine) counterparts. Experimental structural, spectroscopic, and chemical data are fully supported by high-level calculations.

    20. Hydrogel Materials

      Versatile Biocompatible Polymer Hydrogels: Scaffolds for Cell Growth (pages 978–982)

      Ferdous Khan, Rahul S. Tare, Richard. O. C. Oreffo and Mark Bradley

      Article first published online: 29 DEC 2008 | DOI: 10.1002/anie.200804096

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      Gelling together: A three-dimensional, biocompatible hydrogel (see picture) was generated by combining two cationic polymers, chitosan and poly(ethylenimine). The hydrogels were stable under cell-culture conditions and facilitated cell proliferation, yet prevented dedifferentiation of primary human skeletal cells into fibroblasts. A variety of materials such as DNA, proteins, and peptides can be stably incorporated into the gel network.

    21. Surface Assemblies

      Free-Standing 3 D Supramolecular Hybrid Particle Structures (pages 983–987)

      Xing Yi Ling, In Yee Phang, Wouter Maijenburg, Holger Schönherr, David N. Reinhoudt, G. Julius Vancso and Jurriaan Huskens

      Article first published online: 23 DEC 2008 | DOI: 10.1002/anie.200804596

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      Make a stand: The formation of stable and ordered free-standing particle bridges and hollow capsule structures with controllable sizes and geometries is demonstrated by combining the directed assembly of submicrometer particles, transfer printing, and supramolecular layer-by-layer assembly.

  11. Preview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Review
    11. Communications
    12. Preview
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      Preview: Angew. Chem. Int. Ed. 6/2009 (page 991)

      Article first published online: 13 JAN 2009 | DOI: 10.1002/anie.200990011

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