Chemistry - A European Journal

Cover image for Vol. 14 Issue 35

December 8, 2008

Volume 14, Issue 35

Pages 10859–11247

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. Cover Picture: Development of a Library of N-Substituted Maleimides for the Local Functionalization of Linear Polymer Chains (Chem. Eur. J. 35/2008) (page 10859)

      Sebastian Pfeifer and Jean-François Lutz

      Article first published online: 2 DEC 2008 | DOI: 10.1002/chem.200890143

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      A complete library of N-substituted maleimides is introduced by J.-F. Lutz and S. Pfeifer in their Full Paper on p. 10949 ff. The atom transfer radical copolymerization of these fascinating monomers with styrene allows the design of well-defined macromolecules with tailor-made comonomer sequences. Background painting: nature morte aux livres by Ozias Leduc, 1892. Oil on canvas 32×40 cm. Collection: Musée national des beaux-arts du Québec, n° 98.07. © Musée national des beaux-arts du Québec.

  2. Graphical Abstract

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

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. You have free access to this content
      Fragmentation of Carbohydrate Anomeric Alkoxyl Radicals: New Synthesis of Chiral 1-Fluoro-1-halo-1-iodoalditols (page 10871)

      Cosme G. Francisco, Concepción C. González, Alan R. Kennedy, Nieves R. Paz and Ernesto Suárez

      Article first published online: 2 DEC 2008 | DOI: 10.1002/chem.200890145

      This article corrects:

      Fragmentation of Carbohydrate Anomeric Alkoxyl Radicals: New Synthesis of Chiral 1-Fluoro-1-halo-1-iodoalditols

      Vol. 14, Issue 22, 6704–6712, Article first published online: 23 JUN 2008

  4. News

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

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

      Cobalt- and Nickel-Catalyzed Regio- and Stereoselective Reductive Coupling of Alkynes, Allenes, and Alkenes with Alkenes (pages 10876–10886)

      Masilamani Jeganmohan and Chien-Hong Cheng

      Article first published online: 10 OCT 2008 | DOI: 10.1002/chem.200800904

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      Reductive coupling—many products: Versatility in cobalt- and nickel-catalyzed reductive coupling of alkynes, alkenes, and allenes with activated alkenes providing various alkenes, alkanes, lactones, lactams, and cyclic alcohols in good to excellent yields with high regio- and stereoselectivity is described (see scheme).

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
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    1. Organocatalysis

      Organocatalyzed Highly Enantioselective Michael Additions of Malonates to Enones by Using Novel Primary–Secondary Diamine Catalysts (pages 10888–10891)

      Ying-Quan Yang and Gang Zhao

      Article first published online: 10 NOV 2008 | DOI: 10.1002/chem.200801749

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      Michael addition: Several novel primary–secondary diamine catalysts were readily prepared in three steps from commercially available primary amino acids. The catalysts (such as 1) showed excellent catalytic activity and enantioselectivity (up to 99 % yield, >99 % ee) in the asymmetric Michael additions of malonates to enones.

    2. Multicomponent Reactions

      Synthesis of Furoquinolines by a One-Pot Multicomponent Cascade Reaction Catalyzed by Platinum Complexes (pages 10892–10895)

      José Barluenga, Abraham Mendoza, Félix Rodríguez and Francisco J. Fañanás

      Article first published online: 12 NOV 2008 | DOI: 10.1002/chem.200802146

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      Functionalized furoquinoline derivatives are easily obtained in a one-pot three-component coupling process that involves the reaction of 4-pentyn-1-ol derivatives and N-arylaldimines in the presence of catalytic amounts of a platinum(II) complex (see scheme).

    3. Organocatalysis

      A Secondary Amine Amide Organocatalyst for the Asymmetric Nitroaldol Reaction of α-Ketophosphonates (pages 10896–10899)

      Xiaohong Chen, Jun Wang, Yin Zhu, Deju Shang, Bo Gao, Xiaohua Liu, Xiaoming Feng, Zhishan Su and Changwei Hu

      Article first published online: 6 NOV 2008 | DOI: 10.1002/chem.200801958

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      Mild conditions: A secondary amine–amide organocatalyst 1 has been applied in the asymmetric Henry reaction of α-ketophosphonates. A series of aromatic, heteroaromatic, and aliphatic α-ketophosphonates can be converted into the desired α-hydroxy-β-nitrophosphonates in moderate to high yields with excellent enantioselectivities (up to 99 % ee) under mild conditions. The mechanism of reaction was investigated by theoretical calculations.

    4. Polycarbenes

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      Synthesis of Silver(I) and Gold(I) Complexes with Cyclic Tetra- and Hexacarbene Ligands (pages 10900–10904)

      F. Ekkehardt Hahn, Christian Radloff, Tania Pape and Alexander Hepp

      Article first published online: 12 NOV 2008 | DOI: 10.1002/chem.200801877

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      Treasure complexes: Lutidine-bridged tetraimidazolium salts form macrocyclic mono- and dinuclear silver(I) and gold(I) carbene complexes, whereas the lutidine-bridged hexakis(imidazolin-2-ylidene) ligand reacts with silver(I) to yield complex [1]+, which contains six silver(I) atoms arranged in a hexagon and sandwiched in between two hexacarbene ligands.

    5. Enzymatic Dehydrogenation

      Desaturation of Alkylbenzenes by Cytochrome P450BM3 (CYP102A1) (pages 10905–10908)

      Christopher J. C. Whitehouse, Stephen G. Bell and Luet-Lok Wong

      Article first published online: 10 NOV 2008 | DOI: 10.1002/chem.200801927

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      More than a monooxygenase: Cytochrome P450BM3 (CYP102A1) and its evolved variants have been found to desaturate a range of alkylbenzenes (see scheme). Desaturation levels are heavily influenced by the structural characteristics of the alkyl substituent. With cumene, α-hydroxylation yields are more severely impacted by α-deuteration than desaturation yields.

    6. Metallocene Synthesis

      Highly Ylidic Imidazoline-Based Fulvenes as Suitable Precursors for the Synthesis of Imidazolium-Substituted Metallocenes (pages 10909–10914)

      Doris Kunz, Erik Ø. Johnsen, Birgit Monsler and Frank Rominger

      Article first published online: 10 NOV 2008 | DOI: 10.1002/chem.200801956

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      Fulvene versus zwitterion: Imidazoline-derived fulvenes prepared from CpLi and an uronium salt show the highest known ylidic character for 6,6-diaminofulvenes. This is displayed in the extraordinary long exocyclic double bond of 1.430 Å. Therefore these fulvenes exhibit cyclopentadienylanion-like reactivity, namely, protonation to cyclopentadienes and reaction with iron(II) chloride to give Cp-substituted 2-imidazolium ferrocenes.

    7. Molecular Switches

      Complete Direct and Reverse Optically Induced Valence Tautomeric Interconversion in a Cobalt–Dioxolene Complex (pages 10915–10918)

      Paolo Dapporto, Andrea Dei, Giordano Poneti and Lorenzo Sorace

      Article first published online: 12 NOV 2008 | DOI: 10.1002/chem.200801120

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      A solvent tune: The crystallization solvent affects the temperature and light dependence of the valence tautomeric behaviour of a 1:1 Co–dioxolene compound, thus offering a new possibility of tuning its charge distribution (see figure). This approach paves the way for the development of molecular magnetic materials whose properties may be controlled by chemical means.

    8. Cross-Coupling Reactions

      Synthesis of Diarylamines Catalyzed by Iron Salts (pages 10919–10922)

      Arkaitz Correa, Mónica Carril and Carsten Bolm

      Article first published online: 14 NOV 2008 | DOI: 10.1002/chem.200802018

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      Fe shall overcome! A complementary procedure for the synthesis of diarylamines consisting of an iron-catalyzed N-arylation of acetanilides followed by a subsequent deprotection step is presented. This protocol overcomes the previously observed limitations to prepare such compounds by iron-catalyzed arylations of anilines.

    9. Polyoxometalates

      DCC-Assisted Esterification of a Polyoxometalate-Functionalized Phenol with Carboxylic Acids (DCC: Dicyclohexylcarbodiimide) (pages 10923–10927)

      Li Zhu, Yulin Zhu, Xianggao Meng, Jian Hao, Qiang Li, Yongge Wei and Yuanbin Lin

      Article first published online: 12 NOV 2008 | DOI: 10.1002/chem.200801836

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      POMegranate esterification: The above phenolic hydroxyl functionalized organoimido polyoxometalate (POM) undergoes esterification reaction with carboxylic acids in the presence of dicyclohexylcarbodiimide (DCC), to form POM-functionalized esters, providing a convenient and efficient route to prepare POM-based organic/inorganic hybrid materials.

    10. Platinum(II) Alkynyl Fluxionality

      A Luminescent Trinuclear Platinum(II) Pt3C2 System with a “Naked” C≡C2− Ligand That Fluctuates amongst Three Unsupported Platinum(II) Moieties (pages 10928–10931)

      Keith Man-Chung Wong, Wai Han Lam, Zhong-Yuan Zhou and Vivian Wing-Wah Yam

      Article first published online: 5 NOV 2008 | DOI: 10.1002/chem.200801842

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      Fluxional platinum and “naked” alkynyl rods: The first example of a Pt3C2 complex with a “naked” C≡C2− unit linked to three unsupported platinum(II) fragments has been reported and characterized by X-ray crystallography. An interesting fluxional motion, which involves σ–π alkynyl exchange, has been revealed in solution (see figure). The photophysical properties have been studied and correlate with theoretical calculations.

    11. Non-Innocent Ligands

      Ligand Oxidation of a Deprotonated Bis(picolyl)amine IrI(cod) Complex (pages 10932–10936)

      Cristina Tejel, Miguel A. Ciriano, M. Pilar del Río, Dennis G. H. Hetterscheid, Nearchos Tsichlis i Spithas, Jan M. M. Smits and Bas de Bruin

      Article first published online: 14 NOV 2008 | DOI: 10.1002/chem.200801162

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      Innocent until proven guilty: The bis(2-picolyl)amine (bpa) and related poly(picolyl)amine ligands might not be as innocent as they seem. A double deprotonation of the amine (see scheme) and one of the methylene protons of [Ir(bpa)(cod)]+ is unexpectedly easy and yields the anionic complex [Ir(bpa−2H)(cod)], which is subsequently oxidized to the ligand-centered radical [Ir(bpa−2H)(cod)]. even in the air.

  7. Full Papers

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

      A General Approach to Aza-Heterocycles by Means of Domino Sequences Driven by Hydroformylation (pages 10938–10948)

      Etienne Airiau, Thomas Spangenberg, Nicolas Girard, Angèle Schoenfelder, Jessica Salvadori, Maurizio Taddei and André Mann

      Article first published online: 13 NOV 2008 | DOI: 10.1002/chem.200801795

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      Dominating chemistry! The development of hydroformylative domino reactions of easily accessible vinyl acetamides is described. Extremely regioselective hydroformylation of terminal double bonds provides a transient N-acyliminium that can be trapped by various nucleophiles to give several aza-heterocylic scaffolds in a diastereoselective manner (see scheme).

    2. Polymerization

      Development of a Library of N-Substituted Maleimides for the Local Functionalization of Linear Polymer Chains (pages 10949–10957)

      Sebastian Pfeifer and Jean-François Lutz

      Article first published online: 22 OCT 2008 | DOI: 10.1002/chem.200801237

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      Sequence-controlled polymers: Well-defined polymer chains with local functional groups were synthesized by atom transfer radical copolymerization of an excess of styrene with discrete amounts of N-substituted maleimides. This kinetically-controlled approach is wide in scope and can be applied to a broad library of functional maleimides (see scheme).

    3. Organocatalysis

      Asymmetric 1,4-Addition of Oxazolones to Nitroalkenes by Bifunctional Cinchona Alkaloid Thiourea Organocatalysts: Synthesis of α,α-Disubstituted α-Amino Acids (pages 10958–10966)

      José Alemán, Andrea Milelli, Silvia Cabrera, Efraim Reyes and Karl Anker Jørgensen

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200802030

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      Organocatalysis: An easy and simple synthetic approach to optically active α,α-quaternary α-amino acids using asymmetric organocatalysis is presented. The addition of oxazolones to nitroalkenes catalyzed by thiourea cinchona derivatives achieved the corresponding α,α-quaternary α-amino acid derivatives with good yields, excellent diastereoselectivies (up to 98 % dr), and from moderate to good enantioselectivities (up to 92 % ee, see scheme).

    4. Porphyrinoids

      Regioselective Reactivity of an Asymmetric Tetravalent Di[dihydroxotin(IV)] Bis-Porphyrin Host Driven by Hydrogen-Bond Templation (pages 10967–10977)

      Peter R. Brotherhood, Ian J. Luck, Iain M. Blake, Paul Jensen, Peter Turner and Maxwell J. Crossley

      Article first published online: 4 NOV 2008 | DOI: 10.1002/chem.200801775

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      Stuck on tin: Steric, electronic and cavity effects dictate favourable guest hydrogen-bonding modes at an asymmetric host in the pre-equilibrium to ligand exchange. Kinetic trapping of these favourable hydrogen-bonded modes by subsequent covalent-strength ligand association results in regioselective binding (see figure).

    5. Total Sythesis

      Synthesis and Cannabinoid Receptor Activity of Ketoalkenes from Echinacea pallida and Nonnatural Analogues (pages 10978–10984)

      Michael Egger, Patrina Pellett, Kathrin Nickl, Sarah Geiger, Stephanie Graetz, Roland Seifert, Jörg Heilmann and Burkhard König

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200801579

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      Placebo or not? Using palladium-catalyzed cross-coupling reactions, a simple and versatile synthetic approach to ketoalkenes isolated from Echinacea pallida (see figure) was developed. The natural products with skipped conjugation as well as new conjugated analogues were synthesized in overall good yields using this route and tested for activity at the human cannabinoid receptors to help elucidate a possible mechanism of action for Echinacea products.

    6. Metalloradicals

      Intervalent Bis(μ-aziridinato)MII[BOND]MI Complexes (M=Rh, Ir): Delocalized Metallo-Radicals or Delocalized Aminyl Radicals? (pages 10985–10998)

      Cristina Tejel, Miguel A. Ciriano, Vincenzo Passarelli, José A. López and Bas de Bruin

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200801615

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      Resistance has a cause! How can the nitrogen in rhodium and iridium amido complexes resist protonation with strong acids, and where does the unpaired electron reside upon one electron oxidation? Does it form a metallo-radical (see figure), an aminyl-radical or is it delocalized?

    7. Origins of Homochirality

      Racemic β-Sheets as Templates for the Generation of Homochiral (Isotactic) Peptides from Aqueous Solutions of (RS)-Valine or -Leucine N-Carboxy- anhydrides: Relevance to Biochirogenesis (pages 10999–11009)

      Irina Rubinstein, Gilles Clodic, Gerard Bolbach, Isabelle Weissbuch and Meir Lahav

      Article first published online: 27 OCT 2008 | DOI: 10.1002/chem.200801477

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      β-Sheet success: Depending upon the concentration of the initiator, various racemic β-sheet-like architectures, self-assembled during the polymerization of racemic valine or leucine N-carboxyanhydrides in aqueous solution as initiated by a primary amine, operate as efficient templates in enantioselective chain elongation (see scheme).

    8. DNA/RNA Probes

      Highly Fluorescent Conjugated Pyrenes in Nucleic Acid Probes: (Phenylethynyl)pyrenecarbonyl-Functionalized Locked Nucleic Acids (pages 11010–11026)

      Irina V. Astakhova, Vladimir A. Korshun and Jesper Wengel

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200801077

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      Making light work of probes! Bright emission, an increased ability to form excimers, sensitivity to neighboring base pairs, and high fluorescence quantum yields were observed upon the insertion of (phenylethynyl)pyrene–LNAs (LNA=locked nucleic acid) into oligonucleotides (see picture).

    9. Silanes

      N,N-Dimethylaminopropylsilane: A Case Study on the Nature of Weak Intramolecular Si⋅⋅⋅N Interactions (pages 11027–11038)

      Michael Hagemann, Raphael J. F. Berger, Stuart A. Hayes, Hans-Georg Stammler and Norbert W. Mitzel

      Article first published online: 30 OCT 2008 | DOI: 10.1002/chem.200801273

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      Conformational analysis of silanes: Conformations of the highly flexible, donor-functionalised silane H3Si(CH2)3NMe2 were investigated in the gas phase, the solid state and in solution by quantum chemical methods and joint theoretical/experimental approaches. These showed that the cyclic conformer with Si⋅⋅⋅N interaction, which is exclusively present in the crystal, also exists in the gas phase but is in competition with open-chain conformers without Si⋅⋅⋅N contact (see picture).

    10. Chiral Recognition

      Noncovalent Interactions between ([18]Crown-6)-Tetracarboxylic Acid and Amino Acids: Electrospray-Ionization Mass Spectrometry Investigation of the Chiral-Recognition Processes (pages 11039–11049)

      Pascal Gerbaux, Julien De Winter, David Cornil, Katia Ravicini, Gaëlle Pesesse, Jérôme Cornil and Robert Flammang

      Article first published online: 27 OCT 2008 | DOI: 10.1002/chem.200801372

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      How does the crown fit? Electrospray-ionization mass spectrometry (ESIMS) represents an invaluable tool to study diastereoisomeric ionic complexes formed between amino acids and a chiral crown ether, which acts as a chiral selector, and to allow a clear-cut distinction between enantiomers (see figure). One of the most interesting features of the study is the identification of a nonspecific interaction upon ESIMS analysis.

    11. Cyclometalation

      “Roll-over” Cyclometalation of 2,2′-Bipyridine Platinum(II) Complexes in the Gas Phase: A Combined Experimental and Computational Study (pages 11050–11060)

      Burkhard Butschke, Maria Schlangen, Detlef Schröder and Helmut Schwarz

      Article first published online: 10 NOV 2008 | DOI: 10.1002/chem.200801658

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      Dehydrosulfurization coupled with C[BOND]C-bond formation: In the gas-phase reaction of “roll-over” cyclometalated [Pt(bipy−H)]+ with dimethylsulfide (see scheme) an unprecedented dehydrosulfurization process concomitant with the formation of ethene is observed. [Pt(bipy)(CH3)((CH3)2S)]+ served as a precursor for [Pt(bipy−H)]+ which was for the first time observed in the gas phase. Structure and reactivity were studied by means of DFT calculations as well as extensive labeling experiments.

    12. Macroycles

      Synthesis and Investigation of a Chiral Enterobactin Analogue Based on a Macrocyclic Peptide Scaffold (pages 11061–11068)

      Áron Pintér and Gebhard Haberhauer

      Article first published online: 6 NOV 2008 | DOI: 10.1002/chem.200801552

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      Chirality transfer: The synthesis of a triscatecholamide-type siderophore based on a chiral oxazole-containing peptide scaffold is reported, together with investigations of the solution coordination chemistry by UV absorption and CD spectrophotometric methods. The observed highly diastereoselective octahedral complex formation was confirmed by ab initio modelling.

    13. Cu2S Nanodisks

      The Structure-Controlling Solventless Synthesis and Optical Properties of Uniform Cu2S Nanodisks (pages 11069–11075)

      Yu-Biao Chen, Ling Chen and Li-Ming Wu

      Article first published online: 10 NOV 2008 | DOI: 10.1002/chem.200801447

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      Making a conversion: A layered precursor ([Cu(SC12H25)2]) is converted into small nanoparticles by heat treatment. These small nanoparticles gradually fuse into nanodisks by small-particle aggregation during the ripening process, and eventually crystallize into faceted nanodisks (see figure). The organic byproduct, C12H25SH, plays a very important role in the development of disk morphology.

    14. Transfer Hydrogenation

      pH-Dependent Catalytic Activity and Chemoselectivity in Transfer Hydrogenation Catalyzed by Iridium Complex with 4,4′-Dihydroxy-2,2′-bipyridine (pages 11076–11081)

      Yuichiro Himeda, Nobuko Onozawa-Komatsuzaki, Satoru Miyazawa, Hideki Sugihara, Takuji Hirose and Kazuyuki Kasuga

      Article first published online: 6 NOV 2008 | DOI: 10.1002/chem.200801568

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      pH-Dependent substituent effects: Transfer hydrogenation catalyzed by an iridium catalyst with the 4,4′-dihydroxy-2,2′-bipyridine (DHBP) ligand in a formate solution shows highly pH-dependent catalytic activity. High turnover frequency values of the DHBP complex, which can be more than 1000 times the value of the unsubstituted analogue under basic conditions, were obtained under mild conditions (see figure).

    15. Two-Photon Absorption

      Electronic and Vibronic Contributions to Two-Photon Absorption in Donor–Acceptor–Donor Squaraine Chromophores (pages 11082–11091)

      Shino Ohira, Indranil Rudra, Karin Schmidt, Stephen Barlow, Sung-Jae Chung, Qing Zhang, Jon Matichak, Seth R. Marder and Jean-Luc Brédas

      Article first published online: 29 OCT 2008 | DOI: 10.1002/chem.200801055

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      Squaring up! Many squaraines have been observed to exhibit two-photon absorption at transition energies close to those of the lowest energy one-photon electronic transitions (see scheme). Here, the electronic and vibronic contributions to these low-energy two-photon absorptions are elucidated by performing correlated quantum-chemical calculations on model chromophores that differ in their terminal donor groups.

    16. Cross-Coupling Reactions

      Total Synthesis of Discodermolide: Optimization of the Effective Synthetic Route (pages 11092–11112)

      Elsa de Lemos, François-Hugues Porée, Arnaud Bourin, Julien Barbion, Evangelos Agouridas, Marie-Isabelle Lannou, Alain Commerçon, Jean-François Betzer, Ange Pancrazi and Janick Ardisson

      Article first published online: 30 OCT 2008 | DOI: 10.1002/chem.200801478

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      An efficient and modulable total synthesis of discodermolide (DDM), a unique marine anticancer polyketide, is described including related alternative synthetic approaches. Key steps included the application of a crotyltitanation reaction to yield homoallylic (Z)-O-ene-carbamate alcohols with excellent selectivity and the installation of the C13[DOUBLE BOND]C14 (Z) double bond through a highly selective dyotropic rearrangement (see scheme).

    17. Substituent Effects

      Substituent Effects on the Electrophilic Activity of Nitroarenes in Reactions with Carbanions (pages 11113–11122)

      Sylwia Błażej and Mieczysław Mąkosza

      Article first published online: 5 NOV 2008 | DOI: 10.1002/chem.200800821

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      Vicarious nucleophilic substitution: The electrophilic activities of nitroarenes are expressed as relative rate constants of the addition of the chloromethyl phenyl sulfone carbanion to a series of nitroarenes, and were determined by competitive vicarious nucleophilic substitution reactions under kinetic control. These rate constants can be considered to be a measure of the effect of substituents on the electrophilic activity of nitroarenes.

    18. Porous Photocatalysts

      Heterometal Alkoxides as Precursors for the Preparation of Porous Fe– and Mn–TiO2 Photocatalysts with High Efficiencies (pages 11123–11131)

      Xiao-Xin Zou, Guo-Dong Li, Ming-Yi Guo, Xin-Hao Li, Da-Peng Liu, Juan Su and Jie-Sheng Chen

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200801236

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      Doped catalysts: Crystalline porous M–TiO2 (M=Fe, Mn) photocatalysts (see figure for one example) have been directly synthesised from non- stoichiometric heterometal alkoxides through a simple thermal treatment process. The combination of porosity with metal doping in the TiO2-based material results in highly efficient photocatalysts.

    19. Natural Products

      Total Synthesis and Biological Activity of Neopeltolide and Analogues (pages 11132–11140)

      Viktor V. Vintonyak, Brigitte Kunze, Florenz Sasse and Martin E. Maier

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200801398

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      The novel marine natural product neopeltolide (3) was prepared from lactone 1 and acid 2 (see scheme). In addition, several analogues (5-epi, 11-epi, side chain derivatives) were synthesized. Modifications in the lactone part are tolerated to some degree, whereas shortening the distance between the oxazole and the lactone resulted in a significant loss in activity.

    20. Lithium-Ion Batteries

      A Feasibility Study on the Use of Li4V3O8 as a High Capacity Cathode Material for Lithium-Ion Batteries (pages 11141–11148)

      See-How Ng, Nicolas Tran, Kirill G. Bramnik, Hartmut Hibst and Petr Novák

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200800286

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      Lithiation at a feasible cost! Dense, macro-sized, spherical agglomerates consisting of rod-like Li4V3O8 nanostructures (see SEM image) have been synthesised by chemical lithiation of Li1.1V3O8 precursor materials obtained from the inexpensive and industrially oriented spray-drying technique. When applied in a non-optimised full cell system (vs. graphite), the Li4V3O8 electrode showed promising cycling behaviour, retaining a charge capacity above 130 mAh g−1 beyond 50 cycles.

    21. Iron Complexes

      Unexpected Direct Iron-Fluorine Bonds in Trifluorophosphane Iron Complexes: An Alternative to Bridging Trifluorophosphane and Difluorophosphido Groups (pages 11149–11157)

      Rong Zou, Qian-shu Li, Yaoming Xie, R. Bruce King and Henry F. Schaefer III

      Article first published online: 27 OCT 2008 | DOI: 10.1002/chem.200801248

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      An iron will: The iron trifluorophosphane complexes [Fe(PF3)n] (n=4, 5), [Fe2(PF3)n] (n=8, 9), [H2Fe(PF3)4], and [Fe2(PF2)2(PF3)6] have been studied by density functional theory (see figure). The lowest energy structure for [Fe2(PF3)9] is [(F3P)4Fe[LEFTWARDS ARROW]PF2Fe(F)(PF3)4] with a bridging PF2 group and a direct Fe[BOND]F bond.

    22. Fast Relaxation

      A Novel Ni4 Complex Exhibiting Microsecond Quantum Tunneling of the Magnetization (pages 11158–11166)

      Guillem Aromí, Elisabeth Bouwman, Enrique Burzurí, Chiara Carbonera, J. Krzystek, Fernando Luis, Christoph Schlegel, Joris van Slageren, Stefania Tanase and Simon J. Teat

      Article first published online: 29 OCT 2008 | DOI: 10.1002/chem.200801450

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      Extraordinarily fast relaxation: A novel cluster of the [Ni4] cubane family, formula [Ni4(OH)(OMe)3(Hphpz)4(MeOH)3], (H2phpz=3-methyl-5-(2-hydroxyphenyl)pyrazole; see figure) exhibits an unusually low C1 symmetry. The axial anisotropy of the spin ground state S=4 is affected by transverse terms, which are the likely cause of the fast relaxation of the magnetization observed (Γ>0.667 MHz).

    23. Lanthanide-Based Ionic Liquids

      Energetic Ionic Liquids based on Lanthanide Nitrate Complex Anions (pages 11167–11173)

      Guo-Hong Tao, Yangen Huang, Jerry A. Boatz and Jean'ne M. Shreeve

      Article first published online: 30 OCT 2008 | DOI: 10.1002/chem.200800828

      Thumbnail image of graphical abstract

      Well balanced: A series of ionic liquids Cat+3[Ln(NO3)6]3− (Ln=La, Ce) such as those shown in the picture were synthesized by a simple method using nitrate-containing precursors. According to theoretical calculations, they have potential as propellants, and the salts in which Cat+ is 1,5-diamino-4-methyltetrazolium are the first CO-balanced energetic ionic liquids that are stable to hydrolysis and air.

    24. Ionic Liquids

      Biodegradable Naphthenic Acid Ionic Liquids: Synthesis, Characterization, and Quantitative Structure–Biodegradation Relationship (pages 11174–11182)

      Yinghao Yu, Xingmei Lu, Qing Zhou, Kun Dong, Hongwei Yao and Suojiang Zhang

      Article first published online: 27 OCT 2008 | DOI: 10.1002/chem.200800620

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      On the NAIL: Ten naphthenic acid ionic liquids (NAILs) have been synthesized by the one-pot neutralization of choline and surrogate naphthenic acids. These new NAILs may be attractive in large-scale industrial processes and commercial applications (see picture) because they would be rapidly and completely biodegraded in aquatic environments under aerobic conditions.

    25. Nanotechnology

      New Mechanistic Insight in the Thermal Helix Inversion of Second-Generation Molecular Motors (pages 11183–11193)

      Martin Klok, Martin Walko, Edzard M. Geertsema, Nopporn Ruangsupapichat, Jos C. M. Kistemaker, Auke Meetsma and Ben L. Feringa

      Article first published online: 31 OCT 2008 | DOI: 10.1002/chem.200800969

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      Heat and rotate: A generalisation of the mechanism of the rate-determining step of overcrowded-alkene-based, light-driven, unidirectional molecular motors is described for a series of motors featuring a thiopyran upper half and five-, six- and seven-ring lower halves. Despite a difference in the possible photochemical product, the thermal pathways to return to the most stable isomer can be described by similar geometries for all structures (see figure).

    26. DNA Damage

      Synthesis of DNA Strands Site-Specifically Damaged by C8-Arylamine Purine Adducts and Effects on Various DNA Polymerases (pages 11194–11208)

      Nicolas Böge, Maike I. Jacobsen, Zita Szombati, Sabrina Baerns, Francesca Di Pasquale, Andreas Marx and Chris Meier

      Article first published online: 5 NOV 2008 | DOI: 10.1002/chem.200800979

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      Look at the damage: C8-Arylamine-dG and -dA adducts have been prepared using palladium cross-coupling chemistry (see scheme). These “damaged” nucleosides have been used as their corresponding 5′-O-DMTr-3′-O-phosphoramidites for the automated synthesis of site-specifically modified oligonucleotides. These oligonucleotides have been studied with regard to their hybridisation and conformation, and have been used as templates for primer extension assays with high- and low-fidelity DNA polymerases.

    27. Liquid Crystals

      Supramolecular Chirality and Reversible Chiroptical Switching in New Chiral Liquid-Crystal Azopolymers (pages 11209–11221)

      Joaquín Barberá, Loris Giorgini, Fabio Paris, Elisabetta Salatelli, Rosa M. Tejedor and Luigi Angiolini

      Article first published online: 5 NOV 2008 | DOI: 10.1002/chem.200801246

      Thumbnail image of graphical abstract

      Supramolecular chirality: Linear and star-shaped chiral liquid-crystalline polymers containing L-lactic acid and azobenzene chromophores in the side-chain were prepared. Irradiation with r- (right) or l- (left)-circularly polarised light (CPL) enhances the chirality (graphic: CD spectra of linear (—) and star-shaped (– – –) polymers irradiated with r-CPL (red) or l-CPL (blue)).

    28. Transmetalation Reactions

      Transmetalation Reactions from Fischer Carbene Complexes to Late Transition Metals: A DFT Study (pages 11222–11230)

      Israel Fernández, María J. Mancheño, Rubén Vicente, Luis A. López and Miguel A. Sierra

      Article first published online: 5 NOV 2008 | DOI: 10.1002/chem.200801378

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      Mechanisms of transmetalation: Transmetalation reactions from chromium(0) Fischer carbene complexes to late-transition-metal complexes (palladium(0), copper(I), and rhodium(I)) have been studied computationally by density functional theory (see figure). Moreover, the structure and bonding situation of the so far elusive heterobimetallic complexes are briefly discussed.

    29. Dendrimers

      Donor–Acceptor Interactions in Red-Emitting Thienylbenzene-Branched Dendrimers with Benzothiadiazole Core (pages 11231–11241)

      K. R. Justin Thomas, Tai-Hsiang Huang, Jiann T. Lin, Shin-Chien Pu, Yi-Ming Cheng, Cheng-Chih Hsieh and Chou Pi Tai

      Article first published online: 7 NOV 2008 | DOI: 10.1002/chem.200801694

      Thumbnail image of graphical abstract

      In the red: Donor–acceptor dendrimers that contain thienylbenzene repeating units, red-emitting benzothiadiazole cores, and triarylamine peripheries bearing naphthyl units (see schematic picture) exhibit efficient energy transfer and thus behave as highly luminescent red fluorophores. Moreover, their amorphous nature with high glass transition temperatures (176–201 °C) opens an avenue to application in electroluminescent devices.

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      Preview: Chem. Eur. J. 36/2008 (page 11247)

      Article first published online: 2 DEC 2008 | DOI: 10.1002/chem.200890147

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