Chemistry - A European Journal

Cover image for Vol. 15 Issue 44

November 9, 2009

Volume 15, Issue 44

Pages 11765–12147

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Concept
    6. Communications
    7. Full Papers
    8. Preview
    1. Cover Picture: Role of Environmental Factors on the Structure and Spectroscopic Response of 5′-DNA–Porphyrin Conjugates Caused by Changes in the Porphyrin–Porphyrin Interactions (Chem. Eur. J. 44/2009) (page 11765)

      Angela Mammana, Gennaro Pescitelli, Tomohiro Asakawa, Steffen Jockusch, Ana G. Petrovic, Regina R. Monaco, Roberto Purrello, Nicholas J. Turro, Koji Nakanishi, George A. Ellestad, Milan Balaz and Nina Berova

      Version of Record online: 2 NOV 2009 | DOI: 10.1002/chem.200990173

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      Arctic ocean conditions, that is, high salt concentrations (150 mM NaCl) and low temperatures (≈0 °C) promote the formation of rod-like DNA assemblies via porphyrin–porphyrin stacking interactions as witnessed by the multisignate circular dichroism (CD) signal. In their Full Paper on p. 11853 ff., N. Berova, M. Balaz, G. A. Ellestad et al. demonstrate that the multisignate CD signals originate from a combination of interduplex, end-to-end porphyrin–porphyrin stacking and porphyrin–DNA interactions.

  2. Graphical Abstract

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

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

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

      Synthetic Mimics of Antimicrobial Peptides—A Versatile Ring-Opening Metathesis Polymerization Based Platform for the Synthesis of Selective Antibacterial and Cell-Penetrating Polymers (pages 11784–11800)

      Karen Lienkamp and Gregory N. Tew

      Version of Record online: 1 OCT 2009 | DOI: 10.1002/chem.200900049

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      From antimicrobial peptides to biologically active polymers: The design of synthetic mimics of antimicrobial peptides (SMAMPs) that capture the central physicochemical features of their natural archetypes irrespective of the specific folded form is described (see picture). A discussion on recent efforts to create polymers that display biological activity similar to natural proteins, including antimicrobial and cell-penetrating peptides, is presented

  5. Communications

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

      Resolving Conformation Dichotomy for Y- and T-Shaped Three-Coordinate NiI Carbonyl Complexes with Relativistic DFT Analysis of EPR Fingerprints (pages 11802–11807)

      Piotr Pietrzyk, Katarzyna Podolska and Zbigniew Sojka

      Version of Record online: 29 SEP 2009 | DOI: 10.1002/chem.200901805

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      Three-coordinate conformation dichotomy: DFT calculations of the g and A(61Ni, 13C) tensors allow for distinction between T and Y conformations of three-coordinate carbonyl complexes of NiI. Computational spectroscopy studies showed that both conformations are characterized by diagnostic EPR signals (see figure). The characteristic features of the conformations are expected to be applicable for other three-coordinate complexes.

    2. Heterometallic Single Chain Magnets

      First Heterotrimetallic {3 d-4 d-4 f} Single Chain Magnet, Constructed from Anisotropic High-Spin Heterometallic Nodes and Paramagnetic Spacers (pages 11808–11814)

      Diana Visinescu, Augustin M. Madalan, Marius Andruh, Carine Duhayon, Jean-Pascal Sutter, Liviu Ungur, Willem Van den Heuvel and Liviu F. Chibotaru

      Version of Record online: 5 OCT 2009 | DOI: 10.1002/chem.200902408

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      Three in one: Heterotrimetallic 1D coordination polymers are designed by assembling heteronuclear nodes (see figure), {Cu2Ln}, with paramagnetic octacyanido-metallates, [M(CN)8]3− (M=Mo, W), acting as spacers. By choosing a strongly anisotropic lanthanide (DyIII), a new single chain magnet is obtained.

    3. Isoptope Effects

      Isotope-Sensitive Degenerate [1,3]-Hydrogen Migration versus Competitive Enol–Keto Tautomerization (pages 11815–11819)

      Xinhao Zhang, Waltraud Zummack, Detlef Schröder, Frank A. Weinhold and Helmut Schwarz

      Version of Record online: 6 OCT 2009 | DOI: 10.1002/chem.200902176

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      Non-ergodic behavior: Labeling experiments confirm the non-ergodic behavior of ionized acetone generated from its enol. Based on these findings as well as on highly accurate electronic structure calculations, a novel pathway (see picture) for a degenerate, isotope-sensitive [1,3]-hydrogen migration has been uncovered.

    4. Heterogeneous Catalysis

      Tailored Ru-NHC Heterogeneous Catalysts for Alkene Metathesis (pages 11820–11823)

      Iyad Karamé, Malika Boualleg, Jean-Michel Camus, Tarun K. Maishal, Johan Alauzun, Jean-Marie Basset, Christophe Copéret, Robert J. P. Corriu, Erwan Jeanneau, Ahmad Mehdi, Catherine Reyé, Laurent Veyre and Chloé Thieuleux

      Version of Record online: 15 OCT 2009 | DOI: 10.1002/chem.200901752

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      Suits you sir! Well-defined, active and reusable Ru-NHC heterogeneous catalysts for metathesis of functionalized olefins were obtained by i) designing a tailored hybrid mesostructured material that contains regularly distributed imidazolium units and ii) the subsequent transformation of such imidazolium moieties into Ru-NHC active sites.

    5. Gas Storage

      Triptycene-Based Metal Salphens—Exploiting Intrinsic Molecular Porosity for Gas Storage (pages 11824–11828)

      Jonathan H. Chong, Shahrzad Jooya Ardakani, Kevin J. Smith and Mark J. MacLachlan

      Version of Record online: 16 OCT 2009 | DOI: 10.1002/chem.200902188

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      No supramolecular assembly required: Accessible porous materials were formed solely on the basis of inefficient packing of discrete molecules resulting from their specific structure, which hinders close packing. These highly porous materials demonstrate the potential for adsorption and storage of N2 and H2 gases from molecular solids (see figure).

    6. Asymmetric Synthesis

      Enantio- and Diastereoselective Iodocyclopropanation of Allylic Alcohols by Using a Substituted Zinc Carbenoid (pages 11829–11832)

      Louis-Philippe B. Beaulieu, Lucie E. Zimmer and André B. Charette

      Version of Record online: 5 OCT 2009 | DOI: 10.1002/chem.200902228

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      (Zinc)redible! 2,3-Disubstituted and 2,3-trisubstituted iodocyclopropanes can be accessed in enantiomerically enriched form by using the enantioselective Simmons–Smith iodocyclopropanation of allylic alcohols in the presence of the stoichiometric dioxaborolane chiral ligand. These iodocyclopropanes serve as versatile chiral building blocks towards highly functionalized 1,2,3-trisubstituted cyclopropanes (see scheme).

    7. Hydrogenation

      Aqueous Room-Temperature Gold-Catalyzed Chemoselective Transfer Hydrogenation of Aldehydes (pages 11833–11836)

      Lin He, Ji Ni, Lu-Cun Wang, Feng-Jiao Yu, Yong Cao, He-Yong He and Kang-Nian Fan

      Version of Record online: 1 OCT 2009 | DOI: 10.1002/chem.200901261

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      Green reduction at room temperature: Gold nanoclusters supported on mesostructured ceria matrix (Au/meso-CeO2, see figure) are exceptionally effective for aqueous formate-mediated transfer reduction of a wide range of aldehydes to alcohols with high functional group tolerance at room temperature.

    8. Homogeneous Catalysis

      Gold(I)-Catalyzed Synthesis of Highly Substituted 2-Cyclopentenones from 5-Siloxypent-3-en-1-ynes (pages 11837–11841)

      Sang Eun An, Jihee Jeong, Baburaj Baskar, Joopyung Lee, Junho Seo and Young Ho Rhee

      Version of Record online: 5 OCT 2009 | DOI: 10.1002/chem.200901824

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      More than a protective group! A highly efficient synthesis of 2-cyclopentenones, possessing a quaternary carbon center, from 5-siloxypent-3-en-1-ynes was discovered (see scheme). The reaction proceeded under very mild conditions to provide the products in high yield.

  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. Structure Elucidation

      When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline-Earth-Metal Acetylides (pages 11842–11852)

      Marites A. Guino-o, Jacob S. Alexander, Michael L. McKee, Håkon Hope, Ulrich B. Englich and Karin Ruhlandt-Senge

      Version of Record online: 20 OCT 2009 | DOI: 10.1002/chem.200901538

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      Bent or not bent? The experimental and theoretical analysis of factors responsible for the unusual geometry of heavier alkaline-earth-metal derivatives (see picture) provide unique insight into structure-determining factors in heavy s-block chemistry.

    2. Helical Structures

      Role of Environmental Factors on the Structure and Spectroscopic Response of 5′-DNA–Porphyrin Conjugates Caused by Changes in the Porphyrin–Porphyrin Interactions (pages 11853–11866)

      Angela Mammana, Gennaro Pescitelli, Tomohiro Asakawa, Steffen Jockusch, Ana G. Petrovic, Regina R. Monaco, Roberto Purrello, Nicholas J. Turro, Koji Nakanishi, George A. Ellestad, Milan Balaz and Nina Berova

      Version of Record online: 20 OCT 2009 | DOI: 10.1002/chem.200902029

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      A new twist: We show that CD is a remarkably sensitive and diagnostic method for the detection of conformational and supramolecular changes of porphyrin–DNA conjugates as a function of ionic strength. This is supported by a theoretical explanation of the differences in porphyrin–porphyrin interactions as revealed by the complicated exciton-coupled CD profiles as well as by the fluorescence and resonance light scattering response.

    3. Peptide Foldamers

      Engineering a β-Helical d,l-Peptide for Folding in Polar Media (pages 11867–11877)

      John L. Kulp III and Thomas D. Clark

      Version of Record online: 25 SEP 2009 | DOI: 10.1002/chem.200901129

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      A ring with a twist: Designed cyclic peptide 1 is the first example of a hydrophilic β-hairpin/β helix that folds stably in methanol. By contrast, previous de novo designed β-helical structures have been studied almost exclusively in nonpolar organic solvents. This work represents a step toward developing d,l-peptide foldamers for applications in polar protic solvents and, ultimately, water.

    4. Iridium Complexes

      Ligand-Centred Reactivity of Bis(picolyl)amine Iridium: Sequential Deprotonation, Oxidation and Oxygenation of a “Non-Innocent” Ligand (pages 11878–11889)

      Cristina Tejel, M. Pilar del Río, Miguel A. Ciriano, Eduard J. Reijerse, František Hartl, Stanislav Záliš, Dennis G. H. Hetterscheid, Nearchos Tsichlis i Spithas and Bas de Bruin

      Version of Record online: 29 SEP 2009 | DOI: 10.1002/chem.200901017

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      An unusual double deprotonation of the bpa ligand of [Ir(bpa)(cod)]+ produces the anionic complex [Ir(bpa−2H)(cod)] (middle). The ligand-centred radical (left) obtained after one-electron oxidation is an observable intermediate in the radical chain mono-oxygenation with O2 to form the carboxamido complex (right).

    5. Coordination Polymers

      Bipyridinium Array-Type Porous Polymer Displaying Hydrogen Storage, Charge-Transfer-Type Guest Inclusion, and Tunable Magnetic Properties (pages 11890–11897)

      Qing-Xia Yao, Long Pan, Xu-Hui Jin, Jing Li, Zhan-Feng Ju and Jie Zhang

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200901707

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      Functionalization of porous materials: A carboxylate-appended viologen produces a porous pillared-layer coordination polymer in which the functionalized bipyridinium units act as pillars. This flexible framework enables the compound to show hydrogen storage ability, unusual charge-transfer-type guest inclusion, and tunable magnetic properties (see picture).

    6. DNA Replication

      Inhibition of the In Vitro Replication of DNA by an Aptamer–Protein Complex in an Autonomous DNA Machine (pages 11898–11903)

      Changfeng Zhu, Yanqin Wen, Di Li, Lihua Wang, Shiping Song, Chunhai Fan and Itamar Willner

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/chem.200901275

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      Easily inhibited: An aptamer–protein complex indirectly inhibits DNA replication in vitro, an assumption supported by an isothermal DNA machine. An antithrombin aptamer sequence is rationally encoded in the DNA replication template and when thrombin binds to the template, the formed aptamer–protein complexes become a barrier to the polymerase and indirectly inhibit the DNA replication in static and dynamic modes (see scheme; dNTP=deoxynucleotide triphosphate).

    7. Supramolecular Polymers

      Orthogonally Self-Assembled Multifunctional Block Copolymers (pages 11904–11911)

      Ashootosh V. Ambade, Caroline Burd, Mary Nell Higley, Kamlesh P. Nair and Marcus Weck

      Version of Record online: 22 SEP 2009 | DOI: 10.1002/chem.200801647

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      Supramolecular polymers: Mono- and di-telechelic polymers containing side-chain functionalities were synthesized by ROMP and self-assembled through hydrogen-bonding interactions. The side-chains can be orthogonally functionalized either before or after the block copolymer self-assembly, thereby providing a high degree of control over the copolymer architecture.

    8. Supramolecular Chemistry

      Directional Control and Supramolecular Protection Allowing the Chemo- and Regioselective Transformation of a Triamine (pages 11912–11917)

      David Coquière, Aurélien de la Lande, Olivier Parisel, Thierry Prangé and Olivia Reinaud

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/chem.200901020

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      Do the wrap! A ZnII-funnel complex based on a calix[6]arene ligand acts as a multipoint recognition host for polyfunctionalized guests. It wraps and orients an unsymmetrical triamine (red arrow) guest with a high selectivity, allowing its mono-carbamoylation on a preparative scale (TEA = triethylamine). This case study shows that a funnel-like receptor can be used as a supramolecular protecting tool to allow a transformation that is hardly feasible with conventional covalent chemistry.

    9. Terpene Cyclization

      Acid-Catalyzed Cyclization of Terpenes Under Homogeneous and Heterogeneous Conditions as Probed Through Stereoisotopic Studies: A Concerted Process with Competing Preorganized Chair and Boat Transition States (pages 11918–11927)

      Christos Raptis, Ioannis N. Lykakis, Constantinos Tsangarakis and Manolis Stratakis

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200901563

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      Concerted cyclization: It is proposed that the acid-catalyzed cyclization of geranyl acetate proceeds through a concerted mechanism. Under heterogeneous conditions (zeolite Y confinement), a preorganized chairlike transition state predominates, whereas under homogeneous conditions the boat- and chairlike transition states are almost isoenergetic (see graphic).

    10. Functionalised Electrodes

      Covalent Modification of Glassy Carbon Surfaces by Using Electrochemical and Solid-Phase Synthetic Methodologies: Application to Bi- and Trifunctionalisation with Different Redox Centres (pages 11928–11936)

      Jean-Mathieu Chrétien, Mohamed A. Ghanem, Philip N. Bartlett and Jeremy D. Kilburn

      Version of Record online: 25 SEP 2009 | DOI: 10.1002/chem.200901135

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      The covalent bifunctionalisation of glassy carbon (GC) electrodes by two organic redox centres A and B (see picture) has been achieved by using electrochemical and solid-phase synthesis methodologies. After electrochemical immobilisation of ethylenediamine at the GC surface, two organic probes were covalently attached simultaneously and sequentially. The resulting bifunctionalised electrodes were characterised by cyclic voltammetry and differential pulse voltammetry. Trifunctionalisation by three redox centres was also realised.

    11. Lanthanides

      Cationic Allyl Complexes of the Rare-Earth Metals: Synthesis, Structural Characterization, and 1,3-Butadiene Polymerization Catalysis (pages 11937–11947)

      Dominique Robert, Elise Abinet, Thomas P. Spaniol and Jun Okuda

      Version of Record online: 25 SEP 2009 | DOI: 10.1002/chem.200901616

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      Cationic catalysts: Protonolysis of the allyl complexes [Ln(η3-C3H5)3(solvent)] produced cationic allyl complexes of rare-earth metals [Ln(η3-C3H5)3−n(solvent)]n+ (n=1, 2; see figure), which were shown to serve as functional models for multisite polymerization catalysts for 1,3-butadiene.

    12. Natural Products

      A Stereodivergent Synthesis of All Stereoisomers of Centrolobine: Control of Selectivity by a Protecting-Group Manipulation (pages 11948–11953)

      Bernd Schmidt and Frank Hölter

      Version of Record online: 29 SEP 2009 | DOI: 10.1002/chem.200902053

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      Get protected! Depending on the conditions of the final deprotection step, either the natural products (+)- and (−)-centrolobine or their nonnatural epimers are obtained from common precursors (see scheme).

    13. Asymmetric Catalysis

      Catalytic Conjugate Additions of Geminal Bis(sulfone)s: Expanding the Chemistry of Sulfones as Simple Alkyl Anion Equivalents (pages 11954–11962)

      Aitor Landa, Ángel Puente, J. Ignacio Santos, Silvia Vera, Mikel Oiarbide and Claudio Palomo

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200902094

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      Expand your chemistry! Cyclic geminal bis(sulfone)s are able to engage in amine-catalyzed C–C bond-forming reactions involving both 1,2- and 1,4-type acceptors (see scheme). With α,β-unsaturated aldehydes as acceptors and chiral pyrrolidines as catalysts, very high selectivity and generality are attainable. Upon consecutive sulfone α-alkylation and desulfonation of the resulting adducts, useful building blocks are accessible with broad functional-group tolerance and high ee.

    14. Conformation Analysis

      The Stereochemistry of 1,2,3-Triols Revealed by 1H NMR Spectroscopy: Principles and Applications (pages 11963–11975)

      Félix Freire, Enrique Lallana, Emilio Quiñoá and Ricardo Riguera

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/chem.200901505

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      Configuration determination: Empirical and theoretical studies demonstrate that the tris(α-methoxy-α-phenylacetic acid) ester derivatives of 1,2,3-triols form stable conformers in which the contribution of the shielding/deshielding effects from the three auxiliary units can be determined (see picture). The predicted anisotropic effects strongly support the NMR spectra, thus allowing the correlation between the NMR parameters (i.e., ΔδRS of H(3′) and |Δ(ΔδRS)|) and the absolute configuration of the triols.

    15. Natural Products

      Biology-Oriented Combined Solid- and Solution-Phase Synthesis of a Macroline-Like Compound Collection (pages 11976–11984)

      Wolfram Wilk, Andrea Nören-Müller, Markus Kaiser and Herbert Waldmann

      Version of Record online: 25 SEP 2009 | DOI: 10.1002/chem.200901797

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      One route for all: A collection of biologically relevant and isomerically pure cycloocta[b]indoles as the natural-product scaffold of macrolines is described. This scaffold features substitutions at various positions that are generated stereospecifically on a solid support. Subsequent derivatization of the cycloocta[b]indoles in solution allows the scope of the methodology to be extended (see scheme).

    16. Polynuclear Complexes

      Cyclopentadienyl Ruthenium(II) Complexes with Bridging Alkynylphosphine Ligands: Synthesis and Electrochemical Studies (pages 11985–11998)

      Barbara Di Credico, Fabrizia Fabrizi de Biani, Luca Gonsalvi, Annalisa Guerri, Andrea Ienco, Franco Laschi, Maurizio Peruzzini, Gianna Reginato, Andrea Rossin and Piero Zanello

      Version of Record online: 29 SEP 2009 | DOI: 10.1002/chem.200901642

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      Hip to be square: The coordination behaviour of two rigid alkynyl diphosphines towards the CpRu (Cp=cyclopentadienyl) synthon provides access to mononuclear, dinuclear and tetranuclear complexes in which the diphosphine acts as either a terminal or bridging ligand between two CpRu units. A 44-membered macrocyclic square was formed with one of the diphosphines (see scheme).

    17. Sustainable Chemistry

      Synthesis of Early-Transition-Metal Carbide and Nitride Nanoparticles through the Urea Route and Their Use as Alkylation Catalysts (pages 11999–12004)

      Weitang Yao, Philippe Makowski, Cristina Giordano and Frédéric Goettmann

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200901496

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      Urea route to nanoparticles: The use of urea as either a carbon or a nitrogen source enabled the synthesis of various early-transition-metal nitride and carbide nanoparticles (TiN, NbN, Mo2N, W2N, NbCxN1−x, Mo2C and WC, see figure). These particles proved to be very active in promoting the alkylation of ketones and aromatic species with alcohols at 150 °C.

    18. Donor–Acceptor Systems

      Versatile Photophysical Properties of meso-Aryl-Substituted Subporphyrins: Dipolar and Octupolar Charge-Transfer Interactions (pages 12005–12017)

      Shanmugam Easwaramoorthi, Jae-Yoon Shin, Sung Cho, Pyosang Kim, Yasuhide Inokuma, Eiji Tsurumaki, Atsuhiro Osuka and Dongho Kim

      Version of Record online: 22 SEP 2009 | DOI: 10.1002/chem.200901671

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      Eight is enough: Unlike regular porphyrins, a simple change in the meta and para substitution of meso-phenyl subporphyrins completely alters photophysical properties such as dipolar or octupolar charge-transfer (CT; see figure) interactions, solvatochromism, and two-photon absorption.

    19. Electrophilic Addition

      The Ambident Reactivity of 2,4,6-Tris(trifluoromethanesulfonyl)anisole in Methanol: Using the SO2CF3 Group as a Tool to Reach the Superelectrophilic Dimension in σ-Complexation Processes (pages 12018–12029)

      Nizar El Guesmi, Taoufik Boubaker, Regis Goumont and François Terrier

      Version of Record online: 22 SEP 2009 | DOI: 10.1002/chem.200901123

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      Superelectrophilic! The electrophilic reactivity of 2,4,6-tris(trifluoromethanesulfonyl)anisole is shown to surpass that of all other electron-deficient benzene derivatives by several orders of magnitude, which means it falls into the superelectrophilic domain recently defined for Meisenheimer electrophiles (see scheme).

    20. Carboranes

      General Access to Aminobenzyl-o-carboranes as a New Class of Carborane Derivatives: Entry to Enantiopure Carborane–Amine Combinations (pages 12030–12042)

      Vincent Terrasson, José Giner Planas, Damien Prim, Francesc Teixidor, Clara Viñas, Mark E. Light and Michael B. Hursthouse

      Version of Record online: 18 SEP 2009 | DOI: 10.1002/chem.200901332

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      Aminobenzyl-o-carboranes: The synthesis of new aminobenzyl-o-carboranes by a practical three-step procedure is described. The strategy involves the preparation of o-carboranylmethanols followed by chlorination and nucleophilic amination. The expected amines were obtained in good overall yields. The synthetic pathway has also been extended to the synthesis of new enantiopure carborane–amine combinations (see diagram).

    21. Drug Delivery

      Hybrid Organic–Inorganic Silica Gel Carriers with Controlled Drug-Delivery Properties (pages 12043–12049)

      Laura Contessotto, Elena Ghedini, Francesco Pinna, Michela Signoretto, Giuseppina Cerrato and Valentina Crocellà

      Version of Record online: 22 SEP 2009 | DOI: 10.1002/chem.200900603

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      Sol–gel in drug formulation: A reliable procedure has been developed for the design of hybrid silica gel systems with drug-delivery properties. The materials have been prepared by a one-pot synthesis by using a sol–gel approach to achieve high control of the final features of the silica/drug systems (see graphic).

    22. Metal–Organic Frameworks

      Metal–Organic Perovskites: Synthesis, Structures, and Magnetic Properties of [C(NH2)3][MII(HCOO)3] (M=Mn, Fe, Co, Ni, Cu, and Zn; C(NH2)3= Guanidinium) (pages 12050–12064)

      Ke-Li Hu, Mohamedally Kurmoo, Zheming Wang and Song Gao

      Version of Record online: 22 SEP 2009 | DOI: 10.1002/chem.200901605

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      Nice cubes: A family of metal–organic perovskite salts of [C(NH2)3][M(HCOO)3] for divalent Mn to Zn were synthesized from water or water-rich solutions. They possess anionic NaCl-type frameworks of [M(HCOO)3] with guanidinium in the cubic cavities (see figure); the magnetic members show spin-canted antiferromagnetism.

    23. Polyketides

      Polyketide Building Blocks via Diastereoselective Nitrile Oxide Cycloadditions with Homoallylic Alcohols and Monoprotected Homoallylic Diols (pages 12065–12081)

      Nina Lohse-Fraefel and Erick M. Carreira

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200900529

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      A modular approach to Δ2-isoxazolines, latent aldol adducts and polyketide building blocks is reported. The magnesium-mediated, hydroxyl-directed methodology allows diastereoselective access to a wide variety of masked β-hydroxy ketones, starting from readily available aliphatic and aromatic oximes, homoallylic alcohols and monoprotected homoallylic diols (see scheme).

    24. Aromatic Substitution

      Regioselective Arene Functionalization: Simple Substitution of Carboxylate by Alkyl Groups (pages 12082–12091)

      Tobias Krüger, Katja Vorndran and Torsten Linker

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200901774

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      Mono or bis, that is the question: Starting from 1-naphthoic acid, alkyl groups are introduced in only a few steps by Birch reduction and subsequent decarbonylation. High yields and excellent selectivities are obtained, and the degree of alkylation is simply controlled by the addition of tert-butanol (see scheme). Various other aromatic precursors and functional groups are tolerated during this ipso substitution.

    25. ansa Complexes

      Synthesis, Structure and Reactivity of Disila- and Distanna ansa Half-Sandwich Complexes of Molybdenum and Tungsten (pages 12092–12098)

      Holger Bera, Holger Braunschweig, Rainer Dörfler, Kai Hammond, Andreas Oechsner, Krzysztof Radacki and Katharina Uttinger

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200901422

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      High ring strain in the distanna-bridged ansa half-sandwich complex 1 facilitates insertion of elemental chalcogens into the tin–tin bond of the ansa bridge to give complexes with tBu2Sn[BOND]E[BOND]SntBu2 bridges (E=O, S, Se, Te).

    26. Boron Chemistry

      Chemoselective Boron–Carbon Bond Cleavage by Hydroboration of Borirenes (pages 12099–12106)

      Holger Braunschweig, Thomas Herbst, Krzysztof Radacki, Gernot Frenking and Mehmet Ali Celik

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200901749

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      Ring-opening of borirenes (boracyclopropenes) under relatively smooth conditions is achieved through a hydroboration reaction between 1-[bis(trimethylsilyl)amino]-2,3-diethylborirene (1) and 9-borabicyclo[3.3.1]nonane (9-BBN; see scheme).

    27. Organocatalysis

      Minor Enantiomer Recycling: Metal Catalyst, Organocatalyst and Biocatalyst Working in Concert (pages 12107–12113)

      Erica Wingstrand, Anna Laurell, Linda Fransson, Karl Hult and Christina Moberg

      Version of Record online: 18 SEP 2009 | DOI: 10.1002/chem.200901338

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      Walking my baby back home: The minor isomer from a transition-metal-catalyzed reaction is continuously retransferred to the achiral starting material in a process catalyzed by an enzyme. This recycling one-pot procedure results in close to perfect enantioselectivities and improved yields of the desired enantiomer.

    28. Gallium Hydrides

      Oxidative Addition Reactions of Element–Hydrogen Bonds with Different Polarities to a Gallium(I) Compound (pages 12114–12120)

      Annekathrin Seifert, Dominik Scheid, Gerald Linti and Thomas Zessin

      Version of Record online: 24 SEP 2009 | DOI: 10.1002/chem.200901403

      Thumbnail image of graphical abstract

      Gaga for gallium! Oxidative addition reactions of element–hydrogen bonds Sn[BOND]H, O[BOND]H, N[BOND]H, P[BOND]H, and H[BOND]H open a facile way to mixed substituted gallium hydrides (see picture).

    29. Natural Products

      Xanthones and Oxepino[2, 3-b]chromones from Three Endophytic Fungi (pages 12121–12132)

      Karsten Krohn, Simeon F. Kouam, Guy M. Kuigoua, Hidayat Hussain, Stephan Cludius-Brandt, Ulrich Flörke, Tibor Kurtán, Gennaro Pescitelli, Lorenzo Di Bari, Siegfried Draeger and Barbara Schulz

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/chem.200900749

      Thumbnail image of graphical abstract

      Structurally unique ring-expanded, aromatic, and hydrogenated xanthone derivatives (see example) have been isolated from different endophytic fungi. The absolute configuration of the ring-expanded chiral dihydroxanthones was established by a combination of electronic and vibrational circular dichroism spectra (see picture) with DFT calculations. The chemical diversity of the isolated xanthone derivatives is discussed in terms of biosynthesis and chemical transformations.

    30. Porphyrin Nanoparticles

      Enhanced Catalytic Activity and Unexpected Products from the Oxidation of Cyclohexene by Organic Nanoparticles of 5,10,15,20-Tetrakis-(2,3,4,5,6-pentafluorophenyl)porphyrinatoiron(III) in Water by Using O2 (pages 12133–12140)

      Gabriela Smeureanu, Amit Aggarwal, Clifford E. Soll, Julius Arijeloye, Erik Malave and Charles Michael Drain

      Version of Record online: 23 SEP 2009 | DOI: 10.1002/chem.200901086

      Thumbnail image of graphical abstract

      Aggregation is the key: Porphyrin and metalloporphyrin nanoparticles are promising components for advanced materials chemistry. As opposed to typical strategies to increase catalyst activity by separating them on a support, aggregation of [FeIIICl(tppf20)] into dynamic organic nanoparticles results in a greater turnover number for the oxidation of cyclohexene compared with non-aggregated metalloporphyrin.

  7. Preview

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    1. Preview: Chem. Eur. J. 45/2009 (page 12147)

      Version of Record online: 2 NOV 2009 | DOI: 10.1002/chem.200990176

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