Chemistry - A European Journal

Cover image for Vol. 16 Issue 10

March 8, 2010

Volume 16, Issue 10

Pages 2951–3257

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Communications
    7. Full Papers
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    1. Cover Picture: Stable Anticancer Gold(III)–Porphyrin Complexes: Effects of Porphyrin Structure (Chem. Eur. J. 10/2010) (page 2951)

      Raymond Wai-Yin Sun, Carrie Ka-Lei Li, Dik-Lung Ma, Jessie Jing Yan, Chun-Nam Lok, Chung-Hang Leung, Nianyong Zhu and Chi-Ming Che

      Article first published online: 1 MAR 2010 | DOI: 10.1002/chem.201090039

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      Stable gold(III)–porphyrin complexes display promising in vitro cyctotoxic and anti-angiogenic activity as described in the Full Paper by C.-M. Che et al. on page 3097 ff. Strongly chelating phorphyrinato ligands were used to stabilize the gold(III) ion and the structure–bioactivity relationship of a range of compounds was investigated. The biological properties and ease of structural modification of the gold(III)–porphyrins suggest that this family of lipophilic cations would be a suitable choice for the development of future therapeutic applications.

  2. Inside Cover

    1. Top of page
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    3. Inside Cover
    4. Graphical Abstract
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    1. Inside Cover: Strategic Synthesis of 2,6-Pyridylene-Bridged β-to-β Porphyrin Nanorings through Cross-Coupling (Chem. Eur. J. 10/2010) (page 2952)

      Jianxin Song, Pyosang Kim, Naoki Aratani, Dongho Kim, Hiroshi Shinokubo and Atsuhiro Osuka

      Article first published online: 1 MAR 2010 | DOI: 10.1002/chem.201090040

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      Nice necklaces and not just large rings appear to be formed in the reactions described by A. Osuka et al. on page 3009 ff., which enable the efficient synthesis of medium- to large-sized porphyrin nanorings.

  3. Graphical Abstract

    1. Top of page
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    4. Graphical Abstract
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    1. Graphical Abstract: Chem. Eur. J. 10/2010 (pages 2955–2964)

      Article first published online: 1 MAR 2010 | DOI: 10.1002/chem.201090041

  4. News

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

    1. Top of page
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    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Communications
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    1. Three-Component Reactions

      A Three-Component Reaction Based on a Remote-Group-Directed Dynamic Kinetic Aza-Michael Addition: Stereoselective Synthesis of Imidazolidin-4-ones (pages 2972–2976)

      Zhenghu Xu, Tyler Buechler, Kraig Wheeler and Hong Wang

      Article first published online: 11 FEB 2010 | DOI: 10.1002/chem.200903508

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      In control: An α-amino amide reacted with an aldehyde and a Michael acceptor to form stable imidazolidin-4-ones with high stereoselectivity. A dynamic kinetic aza-Michael addition was discovered and applied to the three-component reaction to enforce high stereoselectivity. A remote group was incorporated to invert the reaction process and direct the reaction towards the desired product (see scheme).

    2. Quinone Synthesis

      Straightforward Synthesis of Substituted p-Quinones: Isolation of a Key Intermediate and Use as a Bridging Ligand in a Diruthenium Complex (pages 2977–2981)

      Hari Sankar Das, Fritz Weisser, David Schweinfurth, Cheng-Yong Su, Lapo Bogani, Jan Fiedler and Biprajit Sarkar

      Article first published online: 15 FEB 2010 | DOI: 10.1002/chem.200903409

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      Keep it simple: A new transamination method is reported for the synthesis of diamino-substituted p-quinones (see scheme). Asymmetrically substituted p-quinones are shown to be key intermediates in this reaction. The redox properties of these ligands are discussed and their utility in coordination and redox chemistry is shown with a representative example.

    3. Coordination Polymers

      Metal Dependence of Network Dimensionality in 1,2,4-Diazaphospholide Coordination Polymers (pages 2982–2985)

      Paula Schramm, Andreas Leineweber, Falk Lissner and Dietrich Gudat

      Article first published online: 9 FEB 2010 | DOI: 10.1002/chem.200903184

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      The right to choose: 1,2,4-Diazaphospholide anions support the predictable construction of coordination polymer networks of different topology by switching between bidentate (κNN′) and tridentate (κNN′,κP) coordination depending on the choice of the metal (see picture); furthermore, the ligand exhibits a remarkable difference to 1,2,4-triazolides because the diffuse lone pair at phosphorus permits μ2(P)-bridging coordination.

    4. Antibiotics

      Structure-Based Design of Highly Crowded Ribostamycin/Kanamycin Hybrids as a New Family of Antibiotics (pages 2986–2991)

      Julia Revuelta, Tatiana Vacas, Francisco Corzana, Carlos Gonzalez, Agatha Bastida and Juan Luis Asensio

      Article first published online: 16 FEB 2010 | DOI: 10.1002/chem.200903003

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      Sugar sugar! The synthesis and evaluation of ribostamycin/kanamycin hybrids incorporating a highly crowded trisubstituted aminocyclitol unit that should provide maximum complementation with the RNA receptor are reported (see picture). Analysis shows that the existing conflicts between the different sugar rings can be significantly alleviated by a simple chemical modification, leading to an improvement in activity.

    5. pH Sensors

      Trihydroxytrioxatriangulene—An Extended Fluorescein and a Ratiometric pH Sensor (pages 2992–2996)

      Fredrik Westerlund, Christoffer B. Hildebrandt, Thomas J. Sørensen and Bo W. Laursen

      Article first published online: 9 FEB 2010 | DOI: 10.1002/chem.200902965

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      Fluorescein ver. 2.0: A new, highly fluorescent, pH-sensitive trihydroxytrioxatriangulenium dye (H-TOTA) has been synthesised and characterised. The dye is closely related to fluorescein and may be considered to be a two-dimensional extended version. This new dye can exist in four different protonation states (see graphic) depending on the pH, and its use as a sensitive fluorescent ratiometric pH probe in a physiological buffer is demonstrated.

    6. Molecular Switches

      Squaraine-Based [2]Rotaxanes that Function as Visibly Active Molecular Switches (pages 2997–3000)

      Sheng-Yao Hsueh, Chien-Chen Lai and Sheng-Hsien Chiu

      Article first published online: 15 FEB 2010 | DOI: 10.1002/chem.200903304

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      In a flash! A squaraine-based optical molecular switch functions with striking fluorescence signal changes that are visible to the naked eye (see figure).

    7. Vesicles

      Poly(ethylene glycol)-Graft-Hollow Silica Vesicles for Drug Delivery (pages 3001–3004)

      Chee Leng Lay, Hui Qi Liu, Decheng Wu and Ye Liu

      Article first published online: 11 FEB 2010 | DOI: 10.1002/chem.200903291

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      Delivery by stealth: Vesicles with porous silica shell layers and poly(ethylene glycol) (PEG) stealth layers have good stability, due to the silica layers, good dispersity in aqueous solution, without aggregation due to the PEG stealth layers, low cytotoxicity, and the capability to enter cells (see figure).

    8. Heterocycles

      Cyclizations via Frustrated Lewis Pairs: Lewis Acid Induced Intramolecular Additions of Amines to Olefins and Alkynes (pages 3005–3008)

      Tanja Voss, Chao Chen, Gerald Kehr, Elisa Nauha, Gerhard Erker and Douglas W. Stephan

      Article first published online: 8 FEB 2010 | DOI: 10.1002/chem.200903483

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      Intramolecular additions of amines to olefinic and acetylenic residues in the presence of B(C6F5)3 affords a “frustrated Lewis Pair” strategy to five- and six-membered-ring heterocyclic ammonium borate derivatives (see picture).

    9. Macrocycles

      Strategic Synthesis of 2,6-Pyridylene-Bridged β-to-β Porphyrin Nanorings through Cross-Coupling (pages 3009–3012)

      Jianxin Song, Pyosang Kim, Naoki Aratani, Dongho Kim, Hiroshi Shinokubo and Atsuhiro Osuka

      Article first published online: 19 FEB 2010 | DOI: 10.1002/chem.200903177

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      The bridge determines the size of the loop? Palladium-catalyzed cross-coupling of borylporphyrins led to the construction of β-pyridine-bridged porphyrin nanorings in good yields (around 55–60 %; see scheme). The photophysical study revealed that these nanorings exhibit weakly coupled chromophores and longer fluorescent lifetimes, which is an apparent advantage in the process of efficient excited energy transfer.

  6. Full Papers

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

      Electronic Structure and Reactivity of a [1],[1]Disilamolybdenocenophane (pages 3014–3020)

      Thomas Arnold, Holger Braunschweig, Manuela Gross, Martin Kaupp, Robert Müller and Krzysztof Radacki

      Article first published online: 9 FEB 2010 | DOI: 10.1002/chem.200902883

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      A surprisingansa! The electronic structure of [1],[1]disilamolybdenocenophane has been analyzed by means of DFT. As predicted from the metal-based nucleophilicity and strained geometry, remarkable reactivity towards nonpolar and polar unsaturated organic substrates has been observed. For instance, treatment with tert-butylisonitrile leads to a highly unusual structural motif, an ansa-carbene (see scheme).

    2. Asymmetric Organocatalysis

      Mechanistic Investigation of Chiral Phosphoric Acid Catalyzed Asymmetric Baeyer–Villiger Reaction of 3-Substituted Cyclobutanones with H2O2 as the Oxidant (pages 3021–3035)

      Senmiao Xu, Zheng Wang, Yuxue Li, Xumu Zhang, Haiming Wang and Kuiling Ding

      Article first published online: 27 JAN 2010 | DOI: 10.1002/chem.200902698

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      Bifunctional catalysis: Excellent agreement between experimental observations and theoretical calculations was found in the understanding of the mechanism of the chiral phosphoric acid catalyzed asymmetric Baeyer–Villiger reaction of cyclobutanones with H2O2 as the oxidant. The transition state for the reaction is depicted.

    3. DNA Recognition

      Guanidiniocarbonylpyrrole–Aryl Derivatives: Structure Tuning for Spectrophotometric Recognition of Specific DNA and RNA Sequences and for Antiproliferative Activity (pages 3036–3056)

      Laura Hernandez-Folgado, Domagoj Baretić, Ivo Piantanida, Marko Marjanović, Marijeta Kralj, Thomas Rehm and Carsten Schmuck

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200901999

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      DNA sensors: A systematic study of guanidiniocarbonylpyrrole–aryl derivatives designed to interact with DNA or RNA both through intercalation and through groove binding is presented. Distinctively different interactions with either DNA or RNA are seen by UV/Vis, fluorescence and CD spectroscopy. Compound 1 (see graphic), for example, shows base-pair-selective recognition of ds-DNA.

    4. Base Pairing

      Theoretical Studies on the Intermolecular Interactions of Potentially Primordial Base-Pair Analogues (pages 3057–3065)

      Judit E. Šponer, Álvaro Vázquez-Mayagoitia, Bobby G. Sumpter, Jerzy Leszczynski, Jiří Šponer, Michal Otyepka, Pavel Banáš and Miguel Fuentes-Cabrera

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902068

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      Melting temperature versus pKa: Quantum chemical calculations on the Watson–Crick-type base pairing and stacking properties of triazine- and aminopyrimidine-based primordial informational oligomers (see graphic) show that neither the intrinsic base pairing nor the stacking interactions are responsible for the experimentally observed relationship between the pKa values of the participating heterocycles and the melting points of the duplexes.

    5. Organic gelators

      Positionally Isomeric Organic Gelators: Structure–Gelation Study, Racemic versus Enantiomeric Gelators, and Solvation Effects (pages 3066–3082)

      Vesna Čaplar, Leo Frkanec, Nataša Šijaković Vujičić and Mladen Žinić

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902342

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      Positionally isomeric gelators: Members of a series of positionally isomeric gelators based on long alkyl chains, a hydrogen-bonding phenylglycine unit, and a terminal carboxylic acid or sodium carboxylate moiety (see figure) have been found to display significantly different gelation properties. Dramatic differences in gelator effectiveness (Geff) values of up to 70 times could be observed between racemate/enantiomer gelator pairs, an effect that was observable even in the gelation of very similar solvents such as isomeric xylenes.

    6. Biomimetics

      Analysis of a Pentacoordinate Iron Dicarbonyl as Synthetic Analogue of the Hmd or Mono-Iron Hydrogenase Active Site (pages 3083–3089)

      Tianbiao Liu, Bin Li, Codrina V. Popescu, Andrey Bilko, Lisa M. Pérez, Michael B. Hall and Marcetta Y. Darensbourg

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902684

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      Salvation for the guilty: Protonation of a π-delocalizing, non-innocent ligand complex of iron developed as a pentacoordinate, dicarbonyl analogue of the [Fe]-H2ase or Hmd (H2-forming methylene-tetrahydromethanopterin dehydrogenase) enzyme active site, decreases the electron density at iron and engenders CO uptake as expected for d6 FeII and as seen in the [Fe]-H2ase enzyme active site. Deprotonation releases the extrinsic CO and reclaims the pentacoordinate iron in a state of electrophilic deficiency (see picture).

    7. Asymmetric Catalysis

      Iron- and Cobalt-Catalyzed Asymmetric Hydrosilylation of Ketones and Enones with Bis(oxazolinylphenyl)amine Ligands (pages 3090–3096)

      Tomohiko Inagaki, Le Thanh Phong, Akihiro Furuta, Jun-ichi Ito and Hisao Nishiyama

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200903118

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      Chiral bis(oxazolinylphenyl)amines (Bopa-R) proved to be efficient auxiliary ligands for iron and cobalt catalysts that exhibit high activity for asymmetric hydrosilylation of ketones and asymmetric conjugate hydrosilylation of enones to give products such as those shown in the picture (4-morph=morpholino).

    8. Antitumor Agents

      Stable Anticancer Gold(III)–Porphyrin Complexes: Effects of Porphyrin Structure (pages 3097–3113)

      Raymond Wai-Yin Sun, Carrie Ka-Lei Li, Dik-Lung Ma, Jessie Jing Yan, Chun-Nam Lok, Chung-Hang Leung, Nianyong Zhu and Chi-Ming Che

      Article first published online: 16 FEB 2010 | DOI: 10.1002/chem.200902741

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      Fantastic gold! A family of stable lipophilic cations of the type [AuIII(Por)]+ (Por=porphyrinato ligand) display promising in vitro cytotoxic and anti-angiogenic activities, and a synergistic property in cytotoxicity upon co-incubation with the fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI, see graphic).

    9. Ionic Liquids

      Hypergolic N,N-Dimethylhydrazinium Ionic Liquids (pages 3114–3120)

      Yanqiang Zhang, Haixiang Gao, Yong Guo, Young-Hyuk Joo and Jean'ne M. Shreeve

      Article first published online: 4 FEB 2010 | DOI: 10.1002/chem.200902725

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      Fueling the fire: N-Alkyl-N,N-dimethylhydrazinium dicyanamide and nitrocyanamide ionic liquids are hypergolic with white-fuming nitric acid (see graphic). With extremely low vapor pressure, and high thermal and chemical stability, they should be less toxic than hydrazine and its derivatives, and have potential as liquid hypergolic fuels.

    10. Photochemistry

      Photochemistry of Tricyclo[5.2.2.02,6]undeca-4,10-dien-8-ones: An Efficient General Route to Substituted Linear Triquinanes from 2-Methoxyphenols. Total Synthesis of (±)-Δ9(12)-Capnellene (pages 3121–3131)

      Day-Shin Hsu, Yu-Yu Chou, Yen-Shih Tung and Chun-Chen Liao

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902752

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      See the light! Photochemical reactions of a series of tricyclo[5.2.2.02,6]undeca-4,10-dien-8-ones were studied (see scheme). The oxa-di-π-methane rearranged products were further converted to linear triquinanes. This methodology was successfully applied to the total synthesis of (±)-Δ9(12)-capnellene (1).

    11. Nanospheres

      Bimetallic Au–Ni Nanoparticles Embedded in SiO2 Nanospheres: Synergetic Catalysis in Hydrolytic Dehydrogenation of Ammonia Borane (pages 3132–3137)

      Hai-Long Jiang, Tetsuo Umegaki, Tomoki Akita, Xin-Bo Zhang, Masatake Haruta and Qiang Xu

      Article first published online: 1 FEB 2010 | DOI: 10.1002/chem.200902829

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      Bimetallic Au–Ni synergy: Bimetallic gold–nickel nanoparticles (NPs) with diameters of 3–4 nm embedded in silica nanospheres of around 15 nm have been prepared by a reversed-micelle technique and by in situ reduction in an aqueous NaBH4/NH3BH3 solution. The combination of gold and nickel leads to a remarkable synergy not only in terms of catalytic activity (see figure), but also in durability in the hydrolysis of ammonia borane.

    12. Encapsulation in Nanostructures

      Dendronized Triangular Oligo(phenylene ethynylene) Amphiphiles: Nanofibrillar Self-Assembly and Dye Encapsulation (pages 3138–3146)

      Fátima García and Luis Sánchez

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902894

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      Shown the ropes! The rotated π stacking of dendronized oligo(phenylene ethynylene)s (see figure) results in the formation of nanofibrillar structures several micrometers long that can interact by the hydrophilic triethyleneglycol chains to form thicker strands. These supramolecular structures are able to intercalate and release dye molecules.

      Corrected by:

      Corrigendum: Corrigendum: Dendronized Triangular Oligo(phenylene ethynylene) Amphiphiles: Nanofibrillar Self-Assembly and Dye Encapsulation

      Vol. 17, Issue 46, 12846, Article first published online: 4 NOV 2011

    13. Reaction Mechanisms

      Mechanism of the Asymmetric Autocatalytic Soai Reaction Studied by Density Functional Theory (pages 3147–3156)

      Luca Schiaffino and Gianfranco Ercolani

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902543

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      Interplay of three catalytic cycles explains the main features of the Soai reaction (see picture). These are the fully enantioselective catalytic cycle of the homochiral dimers (the dominant one), the catalytic cycle of the heterochiral dimer (in fact ineffective, as required for the Soai reaction to manifest chiral amplification), and the non-enantioselective catalytic cycle of the homochiral dimers (necessary to explain the observed enantioselectivity).

    14. Ligand Design

      A New Heteroleptic Ruthenium(II) Polypyridyl Complex with Long-Wavelength Absorption and High Singlet-Oxygen Quantum Yield (pages 3157–3165)

      Qian-Xiong Zhou, Wan-Hua Lei, Jing-Rong Chen, Chao Li, Yuan-Jun Hou, Xue-Song Wang and Bao-Wen Zhang

      Article first published online: 27 JAN 2010 | DOI: 10.1002/chem.200902563

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      Effective cooperation of the ligands 2,3-bis(2-pyridyl)benzoquinoxaline (dpb) and 4,5,9,16-tetraaza-dibenzo[a,c]naphthacene (dppn) gives the tris-heteroleptic complex [Ru(bpy)(dpb)(dppn)]2+ (bpy=2,2′-bipyridine), which has a metal-to-ligand charge-transfer maximum at 548 nm, a singlet-oxygen quantum yield of 0.43, strong binding affinity towards double-stranded DNA, and thus promising photodynamic activity.

    15. Coordination Chemistry

      Copper(II) Complexes of a Hexadentate Mixed-Donor N3S3 Macrobicyclic Cage: Facile Rearrangements and Interconversions (pages 3166–3175)

      Craig A. Bell, Paul V. Bernhardt, Lawrence R. Gahan, Manuel Martínez, Michael J. Monteiro, Carlos Rodríguez and Clint A. Sharrad

      Article first published online: 4 FEB 2010 | DOI: 10.1002/chem.200902611

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      Cage fighter: In contrast to the typically extreme stability and inertness of metal ions trapped within macrobicyclic cage ligands, the six-coordinate CuII complex of a mixed-donor N3S3 cage ligand rapidly rearranges to a bromide complex (see figure) in which the ligand adopts a novel tetradentate coordination mode.

    16. Phase Transitions

      Solvent-Induced Structural Transition of Self-Assembled Dipeptide: From Organogels to Microcrystals (pages 3176–3183)

      Pengli Zhu, Xuehai Yan, Ying Su, Yang Yang and Junbai Li

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902139

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      From flexible fibrils to hierarchically self-assembled microcrystals: The structural transition from mesostable dipeptide gels to thermodynamically stable microcrystals is achieved merely by addition of the co-solvent; this provides insights into the role of solvents in controlling molecular arrangements (see scheme).

    17. Donor–Acceptor Systems

      Dipolar Compounds Containing Fluorene and a Heteroaromatic Ring as the Conjugating Bridge for High-Performance Dye-Sensitized Solar Cells (pages 3184–3193)

      Chih-Hsin Chen, Ying-Chan Hsu, Hsien-Hsin Chou, K. R. Justin Thomas, Jiann T. Lin and Chao-Ping Hsu

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200903151

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      Dipolar organic dyes containing diarylamine as a donor and fluorene and a heteroaromatic ring as the conjugating bridge (see scheme) have been developed for highly efficient nanocrystalline TiO2 dye-sensitized solar cells (DSSCs). The overall efficiencies of DSSCs range from 4.92–6.88 %, which reach 68–96 % of a standard device of N-719 that was fabricated and measured under the same conditions.

    18. Marine Natural Products

      Nocardiopsins: New FKBP12-Binding Macrolide Polyketides from an Australian Marine-Derived Actinomycete, Nocardiopsis sp. (pages 3194–3200)

      Ritesh Raju, Andrew M. Piggott, Melissa Conte, Zakir Tnimov, Kirill Alexandrov and Robert J. Capon

      Article first published online: 28 JAN 2010 | DOI: 10.1002/chem.200902933

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      Off the coast: A marine-derived actinomycete, Nocardiopsis sp., from a sediment sample collected at the coast of Brisbane, Australia, yielded two new macrolide polyketides, nocardiopsins A (see figure) and B. The nocardiopsins exhibit low-micromolar binding to FKBP12, consistent with their structural and biosynthetic relationship to the immunosuppressive agents FK506 and rapamycin.

    19. Asymmetric Catalysis

      Chiral and Nonchiral [OsX2(diphosphane)(diamine)] (X: Cl, OCH2CF3) Complexes for Fast Hydrogenation of Carbonyl Compounds (pages 3201–3206)

      Walter Baratta, Cinzia Barbato, Santo Magnolia, Katia Siega and Pierluigi Rigo

      Article first published online: 28 JAN 2010 | DOI: 10.1002/chem.200902809

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      The wizard of Os: A novel class of highly modular diphosphane/diamine–osmium complexes (see structures) are found to be extremely active catalysts in the hydrogenation of ketones and aldehydes (substrate/catalyst ratios and turnover frequencies of up to 2×105 and 3×105 h−1, respectively). High enantioselectivity is achieved with the osmium complexes obtained from the new precursor [Os2Cl4{P(m-tolyl)3}5] and the correctly matched chiral ligands.

    20. Superoxide Dismutation

      On the Mechanism of Action of Fullerene Derivatives in Superoxide Dismutation (pages 3207–3214)

      Sílvia Osuna, Marcel Swart  and Miquel Solà

      Article first published online: 29 JAN 2010 | DOI: 10.1002/chem.200902728

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      Fullerene antioxidants: The mechanism for degradation of the biologically relevant superoxide radical (O2.−) involving the tris-malonyl fullerene compound known as C3 was investigated in detail by means of DFT calculations (see figure). The capability of C3 and related fullerenes to remove highly reactive oxygen species is of immediate interest for future applications in the fields of biology and medicine.

    21. Reaction Mechanisms

      Room-Temperature Alkane Reactivity in Zeolites: An H/D Exchange Study (pages 3215–3221)

      Abdelkarim Sani Souna Sido, Stéphane Walspurger, Jérémy Barbiche and Jean Sommer

      Article first published online: 27 JAN 2010 | DOI: 10.1002/chem.200902624

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      Regioselective H/D exchange occurs between isoalkanes and acidic zeolites at room temperature and it is shown that the main factor controlling the reaction is not the accessibility to the acid sites (see scheme). The deuterium-labeling in various small alkanes is best rationalized by mechanistic schemes typical for classic organic chemistry involving carbocationic intermediates related to the intrinsic reactivity of the alkanes.

    22. Solid-State NMR

      A 93Nb Solid-State NMR and Density Functional Theory Study of Four- and Six-Coordinate Niobate Systems (pages 3222–3239)

      John V. Hanna, Kevin J. Pike, Thibault Charpentier, Thomas F. Kemp, Mark E. Smith, Bryan E. G. Lucier, Robert W. Schurko and Lindsay S. Cahill

      Article first published online: 5 FEB 2010 | DOI: 10.1002/chem.200901581

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      Measurement and calculation: A comprehensive variable B093Nb broadline solid-state NMR study of a large suite of niobate-based materials is reported. Correlations involving the elucidated 93Nb NMR parameters suggest that the NbV site is directly influenced by both the immediate oxo environment and the more distant heavy elements comprising the material structure (see figure).

    23. Block Copolymers

      Photocontrolled Living Anionic Polymerization of Phosphorus-Bridged [1]Ferrocenophanes: A Route to Well-Defined Polyferrocenylphosphine (PFP) Homopolymers and Block Copolymers (pages 3240–3250)

      Sanjib K. Patra, George R. Whittell, Simone Nagiah, Cheuk-Lam Ho, Wai-Yeung Wong and Ian Manners

      Article first published online: 16 FEB 2010 | DOI: 10.1002/chem.200902886

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      Soft and controlled: Photocontrolled living anionic ring-opening polymerization (ROP) of phosphorus-bridged [1]ferrocenophanes (see scheme) initiated by the mild nucleophile NaCp allows access to well-defined polyferrocenylphosphines with molecular weight control and narrow polydispersities.

  7. Preview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Communications
    7. Full Papers
    8. Preview
    1. Preview: Chem. Eur. J. 11/2010 (page 3257)

      Article first published online: 1 MAR 2010 | DOI: 10.1002/chem.201090043

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