Chemistry - A European Journal

Cover image for Vol. 15 Issue 9

February 16, 2009

Volume 15, Issue 9

Pages 2007–2227

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
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    1. Cover Picture: Size Selection During Crystallization of Oppositely Charged Nanoparticles (Chem. Eur. J. 9/2009) (page 2007)

      Bartlomiej Kowalczyk, Alexander M. Kalsin, Rafal Orlik, Kyle J. M. Bishop, Alexander Z. Patashinskii, Antoni Mitus and Bartosz A. Grzybowski

      Version of Record online: 6 FEB 2009 | DOI: 10.1002/chem.200990022

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      Oppositely charged nanoparticles characterized by different size distributions can form 3D supracrystals. In their Communication on page 2032 ff., Grzybowski et al. come to the conclusion that, from both the experimental data and the simulations, the growth of 3D crystals is hindered by entropic effects, owing to finite nanoparticle polydispersities.

  2. Graphical Abstract

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    3. Graphical Abstract
    4. News
    5. Minireview
    6. Communications
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  3. News

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  4. Minireview

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    1. Coordination Chemistry

      Use of Tetradentate Monoanionic Ligands for Stabilizing Reactive Metal Complexes (pages 2020–2030)

      Wayne A. Chomitz and John Arnold

      Version of Record online: 21 JAN 2009 | DOI: 10.1002/chem.200801069

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      Ligand scaffolding: The chemist's ability to choose from a wide range of supporting ligands is an important factor in designing new metal complexes. The introduction of new ligand scaffolds with different donor types and coordination numbers allows for the expansion of reaction chemistry at metal centers. This article surveys the use of the tetradentate monoanionic (TMDA) ligands (shown here) with main-group, transition-metal, and f-block elements.

  5. Communications

    1. Top of page
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    1. Nanoparticles

      Size Selection During Crystallization of Oppositely Charged Nanoparticles (pages 2032–2035)

      Bartlomiej Kowalczyk, Alexander M. Kalsin, Rafal Orlik, Kyle J. M. Bishop, Alexander Z. Patashinskii, Antoni Mitus and Bartosz A. Grzybowski

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200802334

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      Opposites attract (selectively): Oppositely charged nanoparticles characterized by different size distributions form 3D supracrystals (see figure) only if the distributions overlap. Crystal quality decreases rapidly with decreasing degree of overlap, and, irrespective of the ratio of particle diameters/charges, no crystals are observed for non-overlapping distributions.

    2. Peptide Antibiotics

      Helical Hairpin Structure of a Potent Antimicrobial Peptide MSI-594 in Lipopolysaccharide Micelles by NMR Spectroscopy (pages 2036–2040)

      Anirban Bhunia, Ayyalusamy Ramamoorthy and Surajit Bhattacharjya

      Version of Record online: 29 JAN 2009 | DOI: 10.1002/chem.200802635

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      Essential understanding: Elucidation of structural requirements and interactions of antimicrobial peptides with lipopolysaccharide (LPS) are essential to understand the mechanism of action of antimicrobial peptides. The highly active antimicrobial peptide MSI-594 (see figure for electrostatic potential surface) acquires a novel helical hairpin structure in complex with LPS. The structure and interactions of MSI-594 with LPS presented here provide important insights into the mechanism of outer membrane permeabilization by antimicrobial peptides.

    3. C[BOND]C Coupling

      Investigation of sp2–sp Coupling for Electron-Enriched Aryl Dihalides under Oxygen-Free Sonogashira Coupling Reaction Conditions Using a Two-Chamber Reaction System (pages 2041–2044)

      Xue-Yi Chen, Charles Barnes, Jerry R. Dias and T. C. Sandreczki

      Version of Record online: 14 JAN 2009 | DOI: 10.1002/chem.200801541

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      Triethylamine hydroiodide crystals were formed during Sonogashira reactions; after complete reaction the solution retains a characteristic light color (see picture). Very sluggish Sonogashira reactions of electron-enriched aryl diiodides have been carried out in high yield in an oxygen-free, two-chamber reaction system. The formation of triethylamine hydroiodide crystals was monitored to determine the completion of reaction.

    4. Coupling Reactions

      Iron-Catalyzed Ligand-Free Three-Component Coupling Reactions of Aldehydes, Terminal Alkynes, and Amines (pages 2045–2049)

      Pinhua Li, Yicheng Zhang and Lei Wang

      Version of Record online: 28 JAN 2009 | DOI: 10.1002/chem.200802643

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      A tri-umph in many respects: The iron-catalyzed ligand-free, one-pot three-component coupling reactions of aldehydes, terminal alkynes, and amines in the presence of 4 A molecular sieves yields the corresponding propargylamines in good to excellent yields, displays a broad substrate scope, and is economical and environmentally friendly (see scheme).

    5. Asymmetric Catalysis

      Stereoselective Synthesis of 2,6-Disubstituted Piperidines Using the Iridium-Catalyzed Allylic Cyclization as Configurational Switch: Asymmetric Total Synthesis of (+)-241 D and Related Piperidine Alkaloids (pages 2050–2054)

      Christian Gnamm, Caroline M. Krauter, Kerstin Brödner and Günter Helmchen

      Version of Record online: 29 JAN 2009 | DOI: 10.1002/chem.200802525

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      Pressing the configurational switch: Use of enantiomeric Ir catalysts allows the vinylpiperidine building blocks 2 a and 2 b to be synthesized with high selectivity. Total syntheses of the dendrobate alkaloid (+)-241 D, its C6-epimer, and a spruce alkaloid are presented as applications.

    6. Asymmetric Synthesis

      Enantioselective Friedel–Crafts Alkylation of Indoles with Alkylidene Malonates Catalyzed by N,N′-Dioxide–Scandium(III) Complexes: Asymmetric Synthesis of β-Carbolines (pages 2055–2058)

      Yanling Liu, Deju Shang, Xin Zhou, Xiaohua Liu and Xiaoming Feng

      Version of Record online: 28 JAN 2009 | DOI: 10.1002/chem.200802210

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      An efficient catalytic asymmetric Friedel–Crafts alkylation of indoles with alkylidene malonates has been developed by using a chiral N,N′-dioxide–Sc(OTf)3 complex as the catalyst (see scheme). Some optically active intermediates containing the indole skeleton have been synthesized, such as indolepropionic acid, tryptamines, and β-carbolines. The coordination between the scandium atom and the chiral N,N′-dioxide compound has been revealed by X-ray structure analysis.

    7. DNAzymes

      Base-Pairing Directed Folding of a Bimolecular G-Quadruplex: New Insights into G-Quadruplex-Based DNAzymes (pages 2059–2063)

      Tao Li, Erkang Wang and Shaojun Dong

      Version of Record online: 9 JAN 2009 | DOI: 10.1002/chem.200801825

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      Base pairs, magic hands: An additional base-pairing duplex is utilized to control the folding topologies of a bimolecular G-quadruplex formed by two G-rich single-stranded DNAs (see picture), which is dependent on the position of base pairs. This study clearly reveals an important intrinsic role of additional base pairs in the G-quadruplex structure, and also provides a clue to the formation mechanism of the G-quadruplex-based DNAzyme.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Minireview
    6. Communications
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    1. Medicinal Chemistry

      Synthesis of a Phosphonate-Linked Aminoglycoside–Coenzyme A Bisubstrate and Use in Mechanistic Studies of an Enzyme Involved in Aminoglycoside Resistance (pages 2064–2070)

      Feng Gao, Xuxu Yan and Karine Auclair

      Version of Record online: 16 JAN 2009 | DOI: 10.1002/chem.200802172

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      Just five steps! The synthesis of a phosphonate-linked aminoglycoside-coenzyme A derivative (see scheme) that includes a Michael addition in water has been realized in just five steps.

    2. Self-Assembly

      Asymmetrically Substituted Benzene-1,3,5-tricarboxamides: Self-Assembly and Odd–Even Effects in the Solid State and in Dilute Solution (pages 2071–2080)

      Patrick J. M. Stals, Maarten M. J. Smulders, Rafael Martín-Rapún, Anja R. A. Palmans and E. W. Meijer

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200802196

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      Molecular organization: Chiral benzene tricarboxamides with methyl substituents at defined positions self-assemble into supramolecular polymers of preferred helicity by three-fold α-helical-type hydrogen bonding. The odd–even effect is operative and all derivatives are liquid crystalline showing a Colho phase (see figure).

    3. Density Functional Calculations

      Influence of the Charge State on the Structures and Interactions of Vancomycin Antibiotics with Cell-Wall Analogue Peptides: Experimental and Theoretical Studies (pages 2081–2090)

      Zhibo Yang, Erich R. Vorpagel and Julia Laskin

      Version of Record online: 20 JAN 2009 | DOI: 10.1002/chem.200802010

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      Charge matters! The charge state significantly influences the conformation and the binding energy between vancomycin antibiotic and bacterial cell-wall analogue peptides (see figure). Surface-induced dissociation (SID) studies provide a quantitative comparison between the stabilities of different charge states of the complex.

    4. Polycyclization Reactions

      Reviewing the Polyolefin Cyclization Reaction of the C35 Polyprene Catalyzed by Squalene-Hopene Cyclase (pages 2091–2100)

      Tsutomu Hoshino, Yuko Kumai and Tsutomu Sato

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200802142

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      A review of the polycyclization reaction of the C35 polyprenoid by squalene-hopene cyclase: Surprisingly, our results completely disagree with a previous publication in which it was reported that a hexacyclic skeleton was constructed as the single product. In our work many tri- and tetracyclic scaffolds were isolated, but no penta- or hexacycles. The reasons for the different results and the mechanism of the polycyclization reaction are discussed (see figure).

      Corrected by:

      Corrigendum: Reviewing the Polyolefin Cyclization Reaction of the C35 Polyprene Catalyzed by Squalene-Hopene Cyclase

      Vol. 15, Issue 30, 7263, Version of Record online: 17 JUL 2009

    5. Coupling Reactions

      Mechanism of the Coupling of Diazonium to Single-Walled Carbon Nanotubes and Its Consequences (pages 2101–2110)

      Grégory Schmidt, Salomé Gallon, Stéphane Esnouf, Jean-Philippe Bourgoin and Pascale Chenevier

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200801801

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      On the tube: The coupling of diazonium ions onto single-walled carbon nanotubes is shown to proceed through a radical chain reaction by kinetic analysis of the absorption peak drop (see picture). Radical species are also revealed by ESR. Metallic (m) nanotubes play a special catalytic role in the functionalization of semiconducting (sc) nanotubes.

    6. Continuous Separation

      Continuous Separation of Racemic 3,5-Dinitrobenzoyl-Amino Acids in a Centrifugal Contact Separator with the Aid of Cinchona-Based Chiral Host Compounds (pages 2111–2120)

      Andrew J. Hallett, Gerard J. Kwant and Johannes G. de Vries

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200800797

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      Resolution through revolution: It is possible to extract 3,5-dinitrobenzoyl-protected amino acids enantioselectively with the aid of a table-top centrifugal contact separator and a catalytic amount of a chiral host compound based on the Cinchona alkaloids. Enantioselectivities of up to 80 % could be reached in a single pass. This allows the development of a process for the continuous separation of racemates.

    7. Homogeneous Catalysis

      Highly Selective Dehydrogenative Silylation of Alkenes Catalyzed by Rhenium Complexes (pages 2121–2128)

      Yanfeng Jiang, Olivier Blacque, Thomas Fox, Christian M. Frech and Heinz Berke

      Version of Record online: 9 JAN 2009 | DOI: 10.1002/chem.200802019

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      Choosy chemicals: Rhenium(I) complexes of type [ReBr2(L)(NO)(PR3)2] (L=H2 (1), CH3CN (2), ethylene (3); R=iPr (a), cyclohexyl (b)) proved to be suitable catalyst precursors for the highly selective dehydrogenative silylation of alkenes. Two types of rhenium(I) hydride species, [ReBrH(NO)(PR3)2] (4) and [ReBr(η2-CH2[DOUBLE BOND]CHR1)H(NO)(PR3)2] (5), were found in the [ReBr2(L)(NO)(PR3)2]-catalyzed dehydrogenative silylation of alkenes.

      Corrected by:

      Corrigendum: Highly Selective Dehydrogenative Silylation of Alkenes Catalyzed by Rhenium Complexes

      Vol. 15, Issue 13, 3039, Version of Record online: 6 MAR 2009

    8. Cycloaddition

      Synthesis of Tricyclic Fused 3-Aminopyridines through Intramolecular CoI-Catalyzed [2+2+2] Cycloaddition between Ynamides, Nitriles, and Alkynes (pages 2129–2139)

      Pierre Garcia, Solenne Moulin, Yves Miclo, David Leboeuf, Vincent Gandon, Corinne Aubert and Max Malacria

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200802301

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      Three-ring circus: An expedient route to tricyclic fused 2-trimethylsilyl-3-aminopyridines exhibiting unprecedented skeletons is described. The key step is a very efficient cobalt-catalyzed [2+2+2] cycloaddition of a polyunsaturated compound displaying an ynamide, an alkyne, and a nitrile functionality (see picture).

    9. Radiopharmaceuticals

      para-Functionalized Aryl-di-tert-butylfluorosilanes as Potential Labeling Synthons for 18F Radiopharmaceuticals (pages 2140–2147)

      Ljuba Iovkova, Björn Wängler, Esther Schirrmacher, Ralf Schirrmacher, Gabriele Quandt, Guido Boening, Markus Schürmann and Klaus Jurkschat

      Version of Record online: 20 JAN 2009 | DOI: 10.1002/chem.200802266

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      Broad spectrum: Novel para-functionalized aryl-di-tert-butylfluorosilanes, p-(tBu2FSi)C6H4X (X=functional group), have been made available and broaden the spectrum of silicon-based 18F acceptors (SiFAs) for potential PET applications. For example, the [18F]maleimido derivative 1 has been employed for the synthesis of [18F]1- labeled rat serum albumin (RSA), the applicability of which for PET has been verified by in vivo experiments.

    10. Asymmetric Catalysis

      Mechanism-Guided Development of VO(salen)X Complexes as Catalysts for the Asymmetric Synthesis of Cyanohydrin Trimethylsilyl Ethers (pages 2148–2165)

      Yuri N. Belokon, William Clegg, Ross W. Harrington, Victor I. Maleev, Michael North, Marta Omedes Pujol, Dmitry L. Usanov and Carl Young

      Version of Record online: 14 JAN 2009 | DOI: 10.1002/chem.200801679

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      Catalyze this! Detailed study of the mechanism of asymmetric cyanohydrin synthesis catalyzed by VO(salen)X complexes (see figure) led to the development of VO(salen)NCS, as the most active vanadium-based catalyst yet developed for this reaction.

    11. Nucleophilic Substitution

      The Interplay between Steric and Electronic Effects in SN2 Reactions (pages 2166–2175)

      Israel Fernández, Gernot Frenking and Einar Uggerud

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200801833

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      Myths of steric hindrance: In contrast with current opinion, energy decomposition analysis shows that the presence of bulky substituents at carbon leads to the release of steric repulsion in the transition state shown in the graphic. It is rather the weakening of the electrostatic attraction, and in particular the loss of attractive orbital interactions, that are responsible for the activation barrier.

    12. Organometallic Chemistry

      Secondary Interactions in Phosphane-Functionalized Group 4 Cycloheptatrienyl–Cyclopentadienyl Sandwich Complexes (pages 2176–2184)

      Susanne Büschel, Ann-Katrin Jungton, Thomas Bannenberg, Sören Randoll, Cristian G. Hrib, Peter G. Jones and Matthias Tamm

      Version of Record online: 14 JAN 2009 | DOI: 10.1002/chem.200802518

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      Twice as reactive: The coordination chemistry of phosphane-functionalized Zr and Hf cycloheptatrienyl–cyclopentadienyl complexes gives rise to unusual secondary interactions associated with the presence of Lewis acidic 16-electron sandwich moieties. These structures can develop weak dative bonds as exemplified by the noncovalent Pd[RIGHTWARDS ARROW]Zr interaction in the heterobimetallic {Zr2Pd} complex (see picture).

    13. Bond Rotation

      Remarkably Slow Rotation about a Single Bond between an sp3-Hybridised Carbon Atom and an Aromatic Ring without ortho Substituents (pages 2185–2189)

      Sarah Murrison, David Glowacki, Christian Einzinger, James Titchmarsh, Stephen Bartlett, Ben McKeever-Abbas, Stuart Warriner and Adam Nelson

      Version of Record online: 20 JAN 2009 | DOI: 10.1002/chem.200802127

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      Look, noorthosubstituents! A series of polycycles were prepared by using a three-component Joullié–Ugi reaction. The rate of rotation about the bond between a highly hindered bridgehead and a phenyl ring with no ortho substituents was measured, and was highly dependent on the substitution. Rotamer half-lives of up to 21 h at 298 K were observed (see figure). Rotamers resulting from this restricted rotation were isolated for the first time.

    14. Inorganic Polymers

      Synthesis and Characterization of Homopolymers and Copolymers Containing closo-[B12H12]2− Boron Cage Derivatives (pages 2190–2199)

      Teshome B. Yisgedu, Xuenian Chen, Scott Schricker, Jon Parquette, Edward A. Meyers and Sheldon G. Shore

      Version of Record online: 14 JAN 2009 | DOI: 10.1002/chem.200801430

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      Chains of cages: Neutral/ionic [B12H12]2− boron-cage-functionalized methacrylate and styrene homopolymers or copolymers (see picture) are non-crystalline solids, Tg increases as the number of B12 cages in the chain of polystyrene increases, and homopolymers retain more weight than the copolymers when heated to 400 °C.

    15. Peptide Coupling

      Diaminoterephthalates: Scaffolds for Combinatorial Chemistry (pages 2200–2209)

      Rebekka Pflantz and Jens Christoffers

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200802151

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      Fluorescent building blocks: Tetracarboxyamides with a central fluorescent diaminoterephthalate unit were prepared from succinyl succinates following a combinatorial-like strategy. The 2,5-diaminoterephthalates (see scheme; PG=protecting group) possess four points of diversification and are introduced as new scaffolds for combinatorial chemistry.

    16. Carbocations

      Intramolecular Methylacridan–Methylacridinium Complexes with a Phenanthrene-4,5-diyl or Related Skeleton: Geometry–Property Relationships in Isolable C[BOND]H Bridged Carbocations (pages 2210–2216)

      Takanori Suzuki, Yasuyo Yoshimoto, Takashi Takeda, Hidetoshi Kawai and Kenshu Fujiwara

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200801769

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      Bridging the gap: Snapshots of 1,6-H-shift precursors indicate that a narrower C[BOND]H⋅⋅⋅C+ separation (D in the ORTEP diagram) in the title complexes induces faster degenerate rearrangement of 1+. A contact distance of less than 2.7 Å is necessary to realize the organic three-center two-electron bond of [C[BOND]H[BOND]C]+, as indicated by extrapolation of the X-ray data.

    17. Nanocrystals

      Phase Transformation in Titania Nanocrystals by the Oriented Attachment Mechanism: The Role of the pH Value (pages 2217–2222)

      Caue Ribeiro, Cristiano M. Barrado, Emerson R. de Camargo, Elson Longo and Edson R. Leite

      Version of Record online: 13 JAN 2009 | DOI: 10.1002/chem.200801019

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      The oriented attachment (OA) mechanism has been investigated as an important process in the formation of anisotropic nanostructures such as depicted. The results showed that the control of a desired phase in this system may be attained by the control of OA mechanism through pH value, obtaining several morphologies.

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    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Minireview
    6. Communications
    7. Full Papers
    8. Preview
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      Preview: Chem. Eur. J. 10/2009 (page 2227)

      Version of Record online: 6 FEB 2009 | DOI: 10.1002/chem.200990025

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