Chemistry - A European Journal

Cover image for Vol. 16 Issue 6

February 8, 2010

Volume 16, Issue 6

Pages 1711–2005

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Review
    7. Communications
    8. Full Papers
    9. Preview
    1. Cover Picture: Step-by-Step Synthesis of the Endohedral Stannaspherene [Ir@Sn12]3− via the Capped Cluster Anion [Sn9Ir(cod)]3− (Chem. Eur. J. 6/2010) (page 1711)

      Jian-Qiang Wang, Saskia Stegmaier, Bernhard Wahl and Thomas F. Fässler

      Version of Record online: 28 JAN 2010 | DOI: 10.1002/chem.201090018

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      [Ir@Sn12]3−represents a missing link between various research areas: 1) the icosahedral stannaspherene endohedrally filled with an Ir atom resembles endohedral fullerenes, as shown in the background, 2) the coordination of the Ir atom by Sn atoms in the discrete intermetalloid anion is reminiscent of intermetallic compounds, such as Ir3Sn7, and 3) the synthesis from the Zintl ion complex as an intermediate step gives new insight into the reaction mechanism for the synthesis of larger intermetalloid clusters. For more details see the Full Paper by T. F. Fässler et al. on page 1793 ff.

  2. Editorial

    1. Top of page
    2. Cover Picture
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Review
    7. Communications
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    1. You have free access to this content
      Frontiers of Chemistry in Paris (page 1714)

      Peter Goelitz

      Version of Record online: 28 JAN 2010 | DOI: 10.1002/chem.200907777

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Review
    7. Communications
    8. Full Papers
    9. Preview
  4. News

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

    1. Top of page
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    3. Editorial
    4. Graphical Abstract
    5. News
    6. Review
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    1. Nanomaterials

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      Carbon Nanotube and Gold-Based Materials: A Symbiosis (pages 1728–1743)

      Rajpal Singh, Thathan Premkumar, Ji-Young Shin and Kurt E. Geckeler

      Version of Record online: 19 JAN 2010 | DOI: 10.1002/chem.200901609

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      The interaction between carbon materials and gold provides access to new hybrid materials with useful properties for various potential applications. Here we provide an overview of the recent progress in this area by exploring the various synthesis approaches and types of assemblies, and study the diverse applications of the resulting composites (see graphic).

  6. Communications

    1. Top of page
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    3. Editorial
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    5. News
    6. Review
    7. Communications
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    1. Protein Structures

      Photochemistry of Visual Pigment in a Gq Protein-Coupled Receptor (GPCR)—Insights from Structural and Spectral Tuning Studies on Squid Rhodopsin (pages 1744–1749)

      Sivakumar Sekharan, Ahmet Altun and Keiji Morokuma

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200903194

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      Chemistry of vision in an invertebrate: A comprehensive QM/MM evaluation of the structure and spectral tuning mechanism of squid rhodopsin is reported for the first time. A negatively charged Glu180 residue is found to be the principal counterion and the strong electrostatic interaction between the 11-cis-retinal chromophore and counterion is responsible for the origin of spectral tuning from gas phase (604 nm) to the protein environment (490 nm).

    2. Organocatalysis

      Enantioselective Synthesis of Cyclopentene Carbaldehydes by a Direct Multicatalytic Cascade Sequence: Carbocyclization of Aldehydes with Alkynes (pages 1750–1753)

      Kim L. Jensen, Patrick T. Franke, Carlos Arróniz, Sara Kobbelgaard and Karl Anker Jørgensen

      Version of Record online: 14 JAN 2010 | DOI: 10.1002/chem.200903405

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      A multicatalytic, asymmetric cascade reaction sequence of α,β-unsaturated aldehydes with alkyne-tethered nucleophiles has been developed. Organocatalytic iminium–enamine catalysis combined with Lewis acid alkyne activation gave cyclopentene carbaldehyde products in good yields and excellent stereoselectivities (see scheme). To highlight the potential of the sequence, a key structure for the preparation of a fusicoccane diterpenoid analogue was synthesized.

    3. Glycosylation

      Highly Alpha-Selective Sialyl Phosphate Donors for Efficient Preparation of Natural Sialosides (pages 1754–1760)

      Che-Hsiung Hsu, Kuo-Ching Chu, Yih-Shyan Lin, Jeng-Liang Han, Yu-Shiang Peng, Chien-Tai Ren, Chung-Yi Wu and Chi-Huey Wong

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200903035

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      Hubble, bubble, toil, and trouble: The use of a new sialyl phosphate donor allows the stereoselective, one-pot multicomponent synthesis of α-sialooligosaccharides (see scheme).

    4. Molecular Complexes

      Features of the C[BOND]H⋅⋅⋅N Weak Hydrogen Bond and Internal Dynamics in Pyridine–CHF3 (pages 1761–1764)

      Laura B. Favero, Barbara M. Giuliano, Assimo Maris, Sonia Melandri, Paolo Ottaviani, Biagio Velino and Walther Caminati

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200902852

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      All change: The dynamics, location, and hydrogen-bond features of CHF3 change drastically on going from the benzene–CHF3 to the pyridine–CHF3 molecular adduct. The barrier to internal rotation increases from almost nothing to ≈0.6 kJ mol−1; the CHF3 moiety moves into the ring plane from above, and a C[BOND]H⋅⋅⋅N linkage replaces the C[BOND]H⋅⋅⋅π contact (see figure).

    5. Synthetic Methods

      The “Flash” Method: A Shortcut for Producing the Csx(W,Nb)5O14 Structure (pages 1765–1767)

      Anikó Simon and Evgenii V. Kondratenko

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200903001

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      In a flash! A novel synthetic method for the formation of materials with Csx(W,Nb)5O14 structure is introduced. This flash method is based on a cellulose-templated technique and convinces with a short preparation time, a high yield of the crystalline product, and a minor elemental leakage compared to the standard slurry and hydrothermal methods.

    6. Self-Assembly

      Unexpected Isolation of a Pentameric Metallomacrocycle from the FeII-Mediated Complexation of 120° Juxtaposed 2,2′:6′,2′′-Terpyridine Ligands (pages 1768–1771)

      Yi-Tsu Chan, Charles N. Moorefield, Monica Soler and George R. Newkome

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200902988

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      Pentamer—the black sheep in the family! FeII-mediated complexation of acetyl-protected, carbohydrate-functionalized 3,5-di(2,2′:6′,2′′-terpyridinyl)arenes possessing a 120° angle between two terpyridines afforded the predesigned hexamer and the unexpected pentamer (see scheme); both formed self-assembled nanofibers.

    7. C[BOND]H Activation

      Copper-Mediated Direct Cross-Coupling of 1,3,4-Oxadiazoles and Oxazoles with Terminal Alkynes (pages 1772–1775)

      Masanori Kitahara, Koji Hirano, Hayato Tsurugi, Tetsuya Satoh and Masahiro Miura

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200902916

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      The simplest coupling: Copper-mediated direct oxidative cross-coupling of 1,3,4-oxadiazoles and oxazoles with terminal alkynes proceeds through cleavage of sp2 C[BOND]H and sp C[BOND]H bonds to furnish the corresponding alkynylazoles in good yields. The reaction is tolerant toward various substitution patterns of substrates and allows the facile construction of azole-core π-conjugated systems.

    8. Green Chemistry

      Fluorous 4-N,N-Dimethylaminopyridine (DMAP) Salts as Simple Recyclable Acylation Catalysts (pages 1776–1779)

      Daniela Vuluga, Julien Legros, Benoit Crousse and Danièle Bonnet-Delpon

      Version of Record online: 8 JAN 2010 | DOI: 10.1002/chem.200902982

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      Pass the salt please! A simple fluorous salt of 4-N,N-dimethylaminopyridine (C7F15CO2HDMAP) that acts as an effective recyclable organocatalyst for esterification under solvent- and base-free conditions is reported. This catalyst is readily accessible, easy to handle and to recover, and constitutes an attractive alternative for cleaner and safer acylation reactions (see scheme).

    9. Reaction Mechanisms

      Reaction Mechanism for the LiCl-Mediated Directed Zinc Insertion: A Computational and Experimental Study (pages 1780–1784)

      Ching-Yuan Liu, Xuan Wang, Taniyuki Furuyama, Shuji Yasuike, Atsuya Muranaka, Keiji Morokuma and Masanobu Uchiyama

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200902957

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      Tired of wondering about the role of LiCl in the DoI reaction of zinc? Kinetic/thermodynamic competitive experiments and DFT calculations were performed to clarify the regioselectivity and reaction mechanism/pathways of lithium chloride-promoted directed zinc insertion into bromobenzenes. The results strongly suggest that the LiCl-containing “push–pull form” transition state (TSb) is formed at an early stage, thus accelerating the reaction rate of zinc insertion. (DoI=directed ortho insertion.)

  7. Full Papers

    1. Top of page
    2. Cover Picture
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Review
    7. Communications
    8. Full Papers
    9. Preview
    1. Redox Chemistry

      Regulatory Peptides Are Susceptible to Oxidation by Metallic Impurities within Carbon Nanotubes (pages 1786–1792)

      Adriano Ambrosi and Martin Pumera

      Version of Record online: 11 JAN 2010 | DOI: 10.1002/chem.200902534

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      The not-so-pretty face of carbon nanotubes: The redox properties of the regulatory peptide L-glutathione are affected by the presence of nickel oxide impurities within single-walled carbon nanotubes. Glutathione is a very important peptide, present in all living cells. The level of glutathione regulates higher-order cell systems including redox regulator proteins. Glutathione is also present in skin whiteners, which are often used in Asian countries (see photo).

    2. Intermetalloid Clusters

      Step-by-Step Synthesis of the Endohedral Stannaspherene [Ir@Sn12]3− via the Capped Cluster Anion [Sn9Ir(cod)]3− (pages 1793–1798)

      Jian-Qiang Wang, Saskia Stegmaier, Bernhard Wahl and Thomas F. Fässler

      Version of Record online: 14 JAN 2010 | DOI: 10.1002/chem.200902815

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      Open to nonmembers: [Ir@Sn12]3− is a unique example of an icosahedral tetrel cluster encapsulating a metal atom that is not a member of Group 10. Single-crystal structure determination shows that the novel Zintl ion cluster has nearly perfect Ih point symmetry. The endohedral [Ir@Sn12]3− cluster was synthesized in two steps (see scheme: blue spheres, Sn atoms; orange spheres, Ir atoms; black line: 1,5-cyclooctadienyl).

    3. Polymerization

      Cobalt-Mediated Radical Coupling (CMRC): An Unusual Route to Midchain-Functionalized Symmetrical Macromolecules (pages 1799–1811)

      Antoine Debuigne, Rinaldo Poli, Julien De Winter, Pascal Laurent, Pascal Gerbaux, Philippe Dubois, Jean-Paul Wathelet, Christine Jérôme and Christophe Detrembleur

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902618

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      Chemistry under control: A controlled cobalt-mediated radical polymerization and radical coupling reaction (CMRP and CMRC) led to well-defined midchain-functionalized symmetrical polymers. New synthetic possibilities, structure of the coupling products, and the CMRC mechanism were examined through a magnifying glass (see figure; PAN=poly(acrylonitrile)).

    4. Heterogeneous Catalysis

      Ionic-Liquid-Grafted Rigid Poly(p-Phenylene) Microspheres: Efficient Heterogeneous Media for Metal Scavenging and Catalysis (pages 1812–1818)

      Shenghai Li, Junhua Wang, Yongli Kou and Suobo Zhang

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902495

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      Support your local catalyst! Guanidinium ionic-liquid-grafted rigid poly(p-phenylene) microspheres are a suitable scaffold for efficient metal scavenging and nanoparticle immobilization (see figure). The combination of nanoparticles and fragments of ionic liquids on the microsphere surfaces enhance the activity and durability of the catalyst.

    5. Molecular Sensors

      Systematic Investigation of Photoinduced Electron Transfer Controlled by Internal Charge Transfer and Its Consequences for Selective PdCl2 Coordination (pages 1819–1825)

      Thomas Schwarze, Wulfhard Mickler, Carsten Dosche, Roman Flehr, Tillmann Klamroth, Hans-Gerd Löhmannsröben, Peter Saalfrank and Hans-Jürgen Holdt

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902281

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      Fluoroionophores consisting of a fluorophore, an alkylene spacer, and a push–pull dithiomaleonitrile receptor were systematically investigated with a view to regulating photoinduced electron transfer by means of intramolecular charge transfer (ICT). The fluorescence properties can be manipulated by varying the fluorophore groups and the spacer length, and fluorescence enhancement on selective complexation of PdCl2 (see scheme) was used to develop a highly sensitive molecular sensor for detecting small quantities of PdII (ca. 100–1000 ng).

    6. Polyaromatic Oligomers

      Regiocontrolled Synthesis of Ethene-Bridged para-Phenylene Oligomers Based on PtII- and RuII-Catalyzed Aromatization (pages 1826–1833)

      Tse-An Chen, Te-Ju Lee, Ming-Yuan Lin, Shariar M. A. Sohel, Eric Wei-Guang Diau, Shie-Fu Lush and Rai-Shung Liu

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902231

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      New BPAHs: The regiocontrolled syntheses of ethene-bridged para-phenylenes is reported in three distinct classes by using PtII- and RuII-catalyzed aromatization (see scheme). The spectra of these regularly growing arrays show a pattern of extensive π conjugation with increasing array sizes, as well as showing that large arrays of these oligomers are prone to twist from planarity.

    7. Fluorescent Probes

      A New Highly Selective and Sensitive Assay for Fluorescence Imaging of .OH in Living Cells: Effectively Avoiding the Interference of Peroxynitrite (pages 1834–1840)

      Ping Li, Ting Xie, Xia Duan, Fabiao Yu, Xu Wang and Bo Tang

      Version of Record online: 11 DEC 2009 | DOI: 10.1002/chem.200901514

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      Lighting up radicals: A new nonredox fluorescent probe to realize the imaging of .OH in living cells (see image) was designed and synthesized. This probe rapidly responded to .OH with a detection limit of 18 pM. It was quite photostable and not very sensitive to the pH value. Other reactive oxygen species and relevant intracellular components did not interfere.

    8. Coordination Networks

      Thermally Stable Porous Hydrogen-Bonded Coordination Networks Displaying Dual Properties of Robustness and Dynamics upon Guest Uptake (pages 1841–1848)

      Ji-Jun Jiang, Lei Li, Mei-Hua Lan, Mei Pan, Andreas Eichhöfer, Dieter Fenske and Cheng-Yong Su

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200901929

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      Dual-functional networks: Assembly of monomeric [Ln(ntb)Cl3] (ntb=tris(benzimidazol-2-ylmethyl)amine) coordination units containing both hydrogen-bond donors and acceptors results in the formation of hydrogen-bonded networks sustained by N[BOND]H⋅⋅⋅Cl or C[BOND]H⋅⋅⋅Cl hydrogen bonds. The polymorphism in the hydrogen-bonded networks gives rise to different channels that show differentiating adsorption of guests.

    9. Ionic Liquids

      Cobalt(II) Complexes of Nitrile-Functionalized Ionic Liquids (pages 1849–1858)

      Peter Nockemann, Michael Pellens, Kristof Van Hecke, Luc Van Meervelt, Johan Wouters, Ben Thijs, Evert Vanecht, Tatjana N. Parac-Vogt, Hasan Mehdi, Stijn Schaltin, Jan Fransaer, Stefan Zahn, Barbara Kirchner and Koen Binnemans

      Version of Record online: 4 DEC 2009 | DOI: 10.1002/chem.200901729

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      Watch this space! The coordinating abilities of nitrile-functionalized pyrrolidinium ionic liquids toward cobalt(II) ions depend on the alkyl spacer length between the nitrogen atom of the pyrrolidinium core and the nitrile functional group (see figure). The crystal structures of the cobalt(II) solvates shown give an insight into the coordination chemistry of these ionic liquids.

    10. Metallocenes

      Transannular Addition of Phenols to 1,1′-Dialkynylferrocenes: Unanticipated Formation of Phenoxy[4]ferrocenophanedienes (pages 1859–1870)

      Jingxiang Ma, Björn Kühn, Thomas Hackl and Holger Butenschön

      Version of Record online: 23 DEC 2009 | DOI: 10.1002/chem.200902492

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      No alkyne metathesis was observed with 1,1′-dialkynylferrocenes using the Mortreux catalyst system. Instead, phenols react in the presence or absence of [Mo(CO)6] with formation of phenoxy[4]ferrocenophanedienes (see figure), presumably via a vinyl cation intermediate.

    11. Glycosylation

      Gold(I)-Catalyzed Glycosylation with Glycosyl ortho-Alkynylbenzoates as Donors: General Scope and Application in the Synthesis of a Cyclic Triterpene Saponin (pages 1871–1882)

      Yao Li, Xiaoyu Yang, Yunpeng Liu, Cunsheng Zhu, You Yang and Biao Yu

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902548

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      A rich, powerful donor: With an activation mechanism and reaction conditions totally different to previous glycosylation reactions, shelf-stable glycosyl ortho-alkynylbenzoates are versatile, efficacious, and generally applicable when used as donors in the present gold(I)-catalyzed protocol (see scheme).

    12. Intermolecular Hydroacylation

      Iridium-Catalyzed Coupling Reaction of Primary Alcohols with 2-Alkynes Leading to Hydroacylation Products (pages 1883–1888)

      Shintaro Hatanaka, Yasushi Obora and Yasutaka Ishii

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902646

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      It's intermolecular! A novel iridium-catalyzed transformation of primary alcohols with 2-alkynes afforded hydroacylation products (see scheme). The experimental mechanistic investigation revealed that the reaction proceeded through the initial formation of homoallylic alcohols followed by dehydrogenation and isomerization, which leads to the hydroacylation products.

    13. Nanotubes

      Cluster-Based Self-Assembly Route toward MoO3 Single-Walled Nanotubes (pages 1889–1896)

      Shi Hu, Xi Ling, Tian Lan and Xun Wang

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902113

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      Construction site: Single-walled MoO3 nanotubes have been synthesized in a water–thiol two-phase system (see figure) and the conditions and mechanism for their production carefully discussed. Based on these results, a new mechanistic viewpoint is presented, combining the traditional synthetic chemistry of nanomaterials with that of polyoxometalates.

    14. Enzyme Inhibitors

      Targeting Bacterial Membranes: NMR Spectroscopy Characterization of Substrate Recognition and Binding Requirements of D-Arabinose-5-Phosphate Isomerase (pages 1897–1902)

      Cristina Airoldi, Silvia Sommaruga, Silvia Merlo, Paola Sperandeo, Laura Cipolla, Alessandra Polissi and Francesco Nicotra

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902619

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      API substrate binding studies: Arabinose-5-phosphate isomerase (API) is an aldo–keto isomerase catalyzing the reversible isomerization of D-ribulose-5-phosphate (Ru5P) to D-arabinose-5-phosphate (A5P), and has an essential role in the survival of Gram-negative bacteria. By exploiting saturation transfer difference (STD) NMR spectroscopy, the structural requirements necessary for KdsD (an API enzyme) substrate recognition and binding were identified with the aim of designing new API inhibitors (see scheme).

    15. Luminescence

      Synthesis and Optical Properties of Europium-Complex-Doped Inorganic/Organic Hybrid Materials Built from Oxo–Hydroxo Organotin Nano Building Blocks (pages 1903–1910)

      Wei-Qiang Fan, Jing Feng, Shu-Yan Song, Yong-Qian Lei, Guo-Li Zheng and Hong-Jie Zhang

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902111

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      Will Eu enter the matrix? Novel hybrid materials doped with europium complexes, using polymer-based oxo–hydroxo butyltin clusters as nano building blocks, have been constructed (see figure), and their structures and optical properties have been investigated.

    16. Semiconductors

      Phenacyl–Thiophene and Quinone Semiconductors Designed for Solution Processability and Air-Stability in High Mobility n-Channel Field-Effect Transistors (pages 1911–1928)

      Joseph A. Letizia, Scott Cronin, Rocio Ponce Ortiz, Antonio Facchetti, Mark A. Ratner and Tobin J. Marks

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200901513

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      Get those electrons moving! In this contribution we report a family of phenacyl–thiophene-based oligomer (see figure) and polymer semiconductors exhibiting solution-processed electron mobility (μe) up to ≈0.3 cm2 V−1 s−1 and an air-stable μe of 0.015 cm2 V−1 s−1.

    17. Photochemistry

      A Panchromatic Supramolecular Fullerene-Based Donor–Acceptor Assembly Derived from a Peripherally Substituted Bodipy–Zinc Phthalocyanine Dyad (pages 1929–1940)

      Yannick Rio, Wolfgang Seitz, Andreas Gouloumis, Purificacion Vázquez, Jonathan L. Sessler, Dirk M. Guldi and Tomás Torres

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902507

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      Long live the hybrid! The synthesis and photophysical properties of a peripherally substituted Bodipy–zinc phthalocyanine dyad that absorbs over much of the visible spectral region are described. Axial coordination of a C60 derivative at phthalocyanine affords an electron donor–acceptor hybrid that, upon photoexcitation, undergoes a sequence of energy- and electron-transfer reactions (see figure).

    18. Microemulsions

      Influence of Gold Nanoparticles of Varying Size in Improving the Lipase Activity within Cationic Reverse Micelles (pages 1941–1950)

      Subhabrata Maiti, Dibyendu Das, Anshupriya Shome and Prasanta Kumar Das

      Version of Record online: 10 DEC 2009 | DOI: 10.1002/chem.200901300

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      Enhanced performance: The activity of lipase is enhanced in cationic reverse micelles doped with gold nanoparticles (GNPs; see picture). The size and concentration of the GNPs were varied to understand their effect on lipase activity. In the presence of larger-sized GNPs (ca. 15–20 nm), the activity of lipase increases up to 2.5-fold higher than in cetyltrimethylammonium bromide (CTAB) reverse micelles without GNPs. This result becomes more significant because GNPs activate lipase selectively in the reverse micelles but deactivate the enzyme in water.

    19. Carbohydrate Mimics

      Synthesis and Affinity Evaluation of a Small Library of Bidentate Cholera Toxin Ligands: Towards Nonhydrolyzable Ganglioside Mimics (pages 1951–1967)

      Pavel Cheshev, Laura Morelli, Marco Marchesi, Črtomir Podlipnik, Maria Bergström and Anna Bernardi

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902469

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      Toxic clean up: Novel cholera toxin ligands were identified by synthesizing and screening a library of bidentate molecules containing both a galactose and a sialic acid fragment (see figure).

    20. Phosphane Catalysis

      PPh3-Catalyzed Reactions of Alkyl Propiolates with N-Tosylimines: A Facile Synthesis of Alkyl 2-[aryl(tosylimino)methyl]acrylate and an Insight into the Reaction Mechanism (pages 1968–1972)

      Huimin Liu, QiongMei Zhang, Limin Wang and Xiaofeng Tong

      Version of Record online: 23 DEC 2009 | DOI: 10.1002/chem.200902105

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      Phosphanomenal! A new PPh3-catalyzed synthesis of alkyl 2-[aryl(tosylimino)methyl]acrylate from propiolates and N-tosylimines has been developed (see scheme). Deuterium-labelling experiments show that the reaction mechanism involves several hydrogen-transfer processes, which strongly rely on the nature of the reaction media. The stable phosphonium–enamine zwitterion, which has an important role in the catalytic cycle, was isolated and characterised by X-ray analysis.

    21. Dinuclear Spin Crossover

      Thermal- and Light-Induced Spin Crossover in a Guest-Dependent Dinuclear Iron(II) System (pages 1973–1982)

      Jarrod J. M. Amoore, Suzanne M. Neville, Boujemaa Moubaraki, Simon S. Iremonger, Keith S. Murray, Jean-François Létard and Cameron J. Kepert

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200901809

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      A question of solvent: The thermal- and light-induced spin-crossover properties of the dinuclear iron(II) complex shown can be controlled by variation of the amount and type of solvent molecules present in the crystal lattice. Either a one- or two-step spin transition can be observed based on solvent type. Furthermore, the photomagnetic properties can be turned ‘on’ or ‘off’ by solvent manipulation.

    22. Amination Catalysts

      A Highly Versatile Catalyst System for the Cross-Coupling of Aryl Chlorides and Amines (pages 1983–1991)

      Rylan J. Lundgren, Antonia Sappong-Kumankumah and Mark Stradiotto

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902316

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      New amination catalysts: A highly active and widely applicable catalyst system for the cross-coupling of aryl chlorides to amines has been developed by employing the structurally simple and robust ligands L1 and L2 (see graphic). Suitable amine partners include primary and secondary aryl and alkyl amines, imines, hydrazones, lithium amide, and ammonia, with typical catalyst loadings of 1–0.02 mol % Pd.

    23. DNA Recognition

      Highly Sensitive Indicator-Free Impedance Sensing of DNA Hybridization Based on Poly(m-aminobenzenesulfonic acid)/TiO2 Nanosheet Membranes with Pulse Potentiostatic Method Preparation (pages 1992–1999)

      Yu-Wei Hu, Tao Yang, Xin-Xing Wang and Kui Jiao

      Version of Record online: 17 DEC 2009 | DOI: 10.1002/chem.200901870

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      Look, no indicator! The electrochemical signal changes of conductive PABSA/TiO2 nanosheet membranes can be used to detect DNA hybridization directly. DNA immobilization and hybridization causes the DNA/PABSA/TiO2 hybrid to undergo changes to its conformational, electroconductive, and interfacial properties, which were monitored by impedance measurements and adopted as signals for indicator-free DNA detection (see figure).

  8. Preview

    1. Top of page
    2. Cover Picture
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Review
    7. Communications
    8. Full Papers
    9. Preview
    1. You have free access to this content
      Preview: Chem. Eur. J. 7/2010 (page 2005)

      Version of Record online: 28 JAN 2010 | DOI: 10.1002/chem.201090020

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