Chemistry - A European Journal

Cover image for Vol. 17 Issue 9

February 25, 2011

Volume 17, Issue 9

Pages 2533–2787

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. Cover Picture: Chloropupukeanolides C–E: Cytotoxic Pupukeanane Chlorides with a Spiroketal Skeleton from Pestalotiopsis fici (Chem. Eur. J. 9/2011) (page 2533)

      Dr. Ling Liu, Dr. Torsten Bruhn, Prof. Dr. Liangdong Guo, Dr. Daniel C. G. Götz, Prof. Dr. Reto Brun, Dr. August Stich, Prof. Dr. Yongsheng Che and Prof. Dr. Gerhard Bringmann

      Article first published online: 17 FEB 2011 | DOI: 10.1002/chem.201190039

      Thumbnail image of graphical abstract

      Terrestrial sources for a novel spiroketal skeleton derived from the chlorinated tricyclo-[4.3.1.03, 7]-decane (pupukeanane) and the 2,6-dihydroxy-4-methylbenzoic acid moieties were found in three highly functionalized secondary metabolites, that is, chloropupukeanolides C–E. G. Bringmann, Y. Che et al. describe the structure determination of these and other metabolites isolated from the scale-up fermentation extract of the plant endophytic fungus Pestalotiopsis fici in their Full Paper on page 2604 ff.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. Inside Cover: A Cationic Dye Triplet as a Unique “Glue” That Can Connect Fully Matched Termini of DNA Duplexes (Chem. Eur. J. 9/2011) (page 2534)

      Dr. Hiromu Kashida, Takamitsu Hayashi, Taiga Fujii and Prof. Dr. Hiroyuki Asanuma

      Article first published online: 17 FEB 2011 | DOI: 10.1002/chem.201190040

      Thumbnail image of graphical abstract

      A unique “glue” composed of cationic p-methylstilbazole tethered on D-threoninols connects DNA duplexes by intermolecular clustering. When the “glue” is attached to the 5′ terminus of a DNA duplex, a dimer of the duplex is formed. Interestingly, the “glue” is more stable than native sticky ends and strongly responds to the stacking interaction with the neighboring base pair. For further details, see the Full Paper by H. Asanuma et al. on page 2614 ff. The yellow bottle in the picture represents traditional Japanese glue (Nori).

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. Graphical Abstract: Chem. Eur. J. 9/2011 (pages 2537–2545)

      Article first published online: 17 FEB 2011 | DOI: 10.1002/chem.201190041

  4. News

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

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

      Enlightened Enzymes: Strategies to Create Novel Photoresponsive Proteins (pages 2552–2560)

      Dr. Ulrich Krauss, Dr. Thomas Drepper and Prof. Dr. Karl-Erich Jaeger

      Article first published online: 8 FEB 2011 | DOI: 10.1002/chem.201002716

      Thumbnail image of graphical abstract

      Photoswitchable enzymes—lights on! The photocontrol of protein functions, enzymatic reactions and thus biological activities in living cells and organisms represents a rapidly developing and interdisciplinary field of research at the interface of chemistry and biology. Recently developed methods employ genetically encoded photoreceptor domain fusions for the spatiotemporal control of protein functions (see graphic).

  6. Communications

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

      The Effect of the Dynamics of Revolving Gates on the Kinetics of Molecular Encapsulation—The Activity/Selectivity Relationship (pages 2562–2565)

      Stephen Rieth and Prof. Jovica D. Badjić

      Article first published online: 26 JAN 2011 | DOI: 10.1002/chem.201003138

      Thumbnail image of graphical abstract

      Gated molecular encapsulation: The relationship between the rate by which guest molecules enter/exit gated hosts and the rate by which gates revolve and thereby open/close the host were investigated. The results of kinetic measurements have indicated that more dynamic hosts are also more selective in trapping guests, thereby revealing an activity/selectivity relationship pertaining molecular recognition events (see figure).

    2. Peptide Synthesis

      Cyclic Peptides with a Diversely Substituted Guanidine Bridge: Solid-Phase Synthesis and Structural Analysis (pages 2566–2570)

      Dr. Youness Touati-Jallabe, Dr. Laurent Chiche, Dr. Abdallah Hamzé, Dr. André Aumelas, Dr. Vincent Lisowski, Dr. Dorothée Berthomieu, Prof. Jean Martinez and Dr. Jean-François Hernandez

      Article first published online: 3 FEB 2011 | DOI: 10.1002/chem.201003299

      Thumbnail image of graphical abstract

      A solid solution! The solid-phase synthesis of original cyclic peptides containing a diversely substituted guanidine bridge is described (see scheme). The guanidine bridge is assumed to be able to adopt four different orientations inside the peptide cycle. NMR and modeling studies of Arg–Gly–Asp-related cyclic peptides showed that the degree of guanidine substitution (R1, R2=H, alkyl) can influence the bridge orientation and, therefore, the peptide conformation.

    3. Polyoxometalates

      Low-Symmetry Uranyl Pyrophosphate Cage Clusters (pages 2571–2574)

      Dr. Jie Ling, Dr. Jie Qiu, Jennifer E. S. Szymanowski and Prof. Peter C. Burns

      Article first published online: 30 JAN 2011 | DOI: 10.1002/chem.201003481

      Thumbnail image of graphical abstract

      Is cluster symmetry so important? The combination of uranyl, peroxide, and pyrophosphate in aqueous solution results in the self-assembly of highly complex clusters (see figure) containing 45 uranyl bipyramids and 23 pyrophosphate groups. These clusters are built from three basic structural units, and are highly unusual because they completely lack symmetry. They provide a window into the complex chemistry of evolving cluster topologies under the conditions of their formation.

    4. Photodegradation

      Dual-Phase Titanate/Anatase with Nitrogen Doping for Enhanced Degradation of Organic Dye under Visible Light (pages 2575–2578)

      Yu Hua Cheng, Dr. Yizhong Huang, Pushkar D. Kanhere, Vishnu P. Subramaniam, Dangguo Gong, Prof. Sam Zhang, Dr. James Highfield, Dr. Martin K. Schreyer and Prof. Zhong Chen

      Article first published online: 31 JAN 2011 | DOI: 10.1002/chem.201002256

      Thumbnail image of graphical abstract

      Synergy at work! A dual-phase photocatalyst comprising anatase and protonated titanate, synthesized by a low-temperature one-pot process, synergistically adsorbs and degrades methylene blue dye under visible light. The two phases (see figure) work harmoniously to give accelerated breakdown of the organic dye.

    5. Nanotubes

      Nature of N 2p, Ti 3d, O 2p Hybridization of N-Doped TiO2 Nanotubes and Superior Photovoltaic Performance through Selective Atomic N Doping (pages 2579–2582)

      Dr. Kyu Sung Han, Dong Ki Lee, Dr. Jung Woo Lee, Ga In Lee and Prof. Jeung Ku Kang

      Article first published online: 2 FEB 2011 | DOI: 10.1002/chem.201001672

      Thumbnail image of graphical abstract

      Mixing it up! N 2p states of N-doped TiO2 nanotubes become predominant near the Fermi level, which is a discrete energy level at the top edge of a valence band, whereas it deteriorates the good hybridization between Ti 3d and O 2p. This leads to a reduced band gap for selective atomic N-doped nanotubes and gives enhanced photovoltaic performance (see graphic).

    6. Asymmetric Catalysis

      Guanidine Organocatalyst for the Asymmetric Mannich-Type Reaction between α-Isothiocyanato Imide and Sulfonyl Imines (pages 2583–2586)

      Xiaohong Chen, Shunxi Dong, Zhen Qiao, Yin Zhu, Mingsheng Xie, Dr. Lili Lin, Dr. Xiaohua Liu and Prof. Dr. Xiaoming Feng

      Article first published online: 26 JAN 2011 | DOI: 10.1002/chem.201002571

      Thumbnail image of graphical abstract

      A highly efficient bisguanidine organocatalyst has been developed for the asymmetric Mannich-type reaction of α-isothiocyanato imide with N-Ts-protected imines (Ts=tosyl, see scheme). A series of aromatic, α,β-unsaturated, heteroaromatic, and aliphatic imines can be converted into the desired α,β-diamino acid derivatives in good to excellent yields with high diastereoselectivities (up to >95:5 d.r.) and excellent enantioselectivities (up to >99 % ee) under mild conditions. The possible transition state of the reaction was also proposed.

    7. N-Substituted Amines

      Ruthenium-Catalyzed Nitro and Nitrile Compounds Coupling with Alcohols: Alternative Route for N-Substituted Amine Synthesis (pages 2587–2591)

      Xinjiang Cui, Dr. Yan Zhang, Dr. Feng Shi and Prof. Youquan Deng

      Article first published online: 26 JAN 2011 | DOI: 10.1002/chem.201003095

      Thumbnail image of graphical abstract

      The one-pot synthesis of N-substituted secondary amines from nitrobenzenes and benzonitriles has been developed (see scheme). This report presents a versatile and simple method for the synthesis of N-substituted amines in excellent yield and high efficiency from nitro and nitrile compounds with alcohols.

    8. Electrophosphorescence

      Fluorene-Based Phosphine Oxide Host Materials for Blue Electrophosphorescence: An Effective Strategy for a High Triplet Energy Level (pages 2592–2596)

      Donghui Yu, Yongbiao Zhao, Dr. Hui Xu, Chunmiao Han, Prof. Dongge Ma, Zhaopeng Deng, Prof. Shan Gao and Prof. Pengfei Yan

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201003434

      Thumbnail image of graphical abstract

      A bolt from the blue! Two novel host materials for blue electrophosphorescence were designed and synthesized by modification of fluorene at the 9-position with diphenylphosphine oxide to give high triplet energy levels of 2.99 eV (see scheme), achieved through an indirect linkage of the chromophore and the phosphine oxide moieties. These host materials were also found to exhibit high thermal and morphological stabilities and efficient energy transfer.

  7. Full Papers

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

      A New Phase in the Binary Iron Nitrogen System?—The Prediction of Iron Pernitride, FeN2 (pages 2598–2603)

      Dr. Michael Wessel and Prof. Dr. Richard Dronskowski

      Article first published online: 2 FEB 2011 | DOI: 10.1002/chem.201003143

      Thumbnail image of graphical abstract

      Accessible at high pressures? Iron pernitride, FeN2, has been predicted by using DFT and finite-temperature phonon calculations. The rhombohedral phase is endothermic but should be accessible at high pressures, namely beyond 17 GPa at a synthesis temperature of 1000 K. The N[BOND]N bond length and the quantum-chemical bond analysis suggest the electron count to be N22−. FeN2 is likely to be a ferromagnetic material with a saturation moment of 1.68 μB per Fe atom.

    2. Natural Products

      Chloropupukeanolides C–E: Cytotoxic Pupukeanane Chlorides with a Spiroketal Skeleton from Pestalotiopsis fici (pages 2604–2613)

      Dr. Ling Liu, Dr. Torsten Bruhn, Prof. Dr. Liangdong Guo, Dr. Daniel C. G. Götz, Prof. Dr. Reto Brun, Dr. August Stich, Prof. Dr. Yongsheng Che and Prof. Dr. Gerhard Bringmann

      Article first published online: 8 FEB 2011 | DOI: 10.1002/chem.201003129

      Thumbnail image of graphical abstract

      Highly functionalized: Chloropupukeanolides C–E (13) are highly functionalized secondary metabolites with a spiroketal skeleton. The elucidation of the absolute stereostructure of 1 succeeded by X-ray crystallography, whereas compounds 2 and 3 were configurationally assigned by a combination of NMR, HPLC, and quantum-mechanical techniques. The compounds showed interesting cytotoxic and anti-infective activities.

    3. Nanostructures

      A Cationic Dye Triplet as a Unique “Glue” That Can Connect Fully Matched Termini of DNA Duplexes (pages 2614–2622)

      Dr. Hiromu Kashida, Takamitsu Hayashi, Taiga Fujii and Prof. Dr. Hiroyuki Asanuma

      Article first published online: 8 FEB 2011 | DOI: 10.1002/chem.201003059

      Thumbnail image of graphical abstract

      Stick together! A unique “glue” of cationic p-methylstilbazoles tethered on D-threoninols connects DNA duplexes by intermolecular clustering. When the “glue” is attached to both termini of a DNA duplex, a nanowire is formed (see graphic). Thus, the “glue” can be utilized for constructing DNA-based nanoarchitectures.

    4. Biocatalysis

      Broadening Deoxysugar Glycodiversity: Natural and Engineered Transaldolases Unlock a Complementary Substrate Space (pages 2623–2632)

      Dr. Madhura Rale, Dr. Sarah Schneider, Prof. Dr. Georg A. Sprenger, Dr. Anne K. Samland and Prof. Dr. Wolf-Dieter Fessner

      Article first published online: 2 FEB 2011 | DOI: 10.1002/chem.201002942

      Thumbnail image of graphical abstract

      Increased glycodiversity: Together, the engineered transaldolase TalBF178Y and wild-type FSA from E. coli offer an exceptionally broad and completely stereoselective access to variously deoxygenated sugar-type products (see figure). The enzymes complement each other's aldol donor substrate selectivity, which has allowed the preparation, out of a [3×8] substrate matrix, of a 22-membered library of ketoses, many of which are inaccessible by available enzymes.

    5. Natural Products

      Total Synthesis of cyclo-Mumbaistatin Analogues through Anionic Homo-Fries Rearrangement (pages 2633–2641)

      Dr. Stefan Neufeind, Nils Hülsken, Dr. Jörg-Martin Neudörfl, Dr. Nils Schlörer and Prof. Dr. Hans-Günther Schmalz

      Article first published online: 27 JAN 2011 | DOI: 10.1002/chem.201003166

      Thumbnail image of graphical abstract

      Try it intramolecular: A novel strategy, exploiting an anionic homo-Fries-rearrangement as a key reaction, has opened an efficient synthetic access to analogues of mumbaistatin, that is, the most potent natural G6P-T1 inhibitor known to date. For the first time, compounds displaying the characteristic spiroketal-lactone motif of cyclo-mumbaistatin such as depicted were prepared.

    6. Hydrocarbons

      Electron-Accepting Dithiarubicene (Emeraldicene) and Derivatives Prepared by Unprecedented Nucleophilic Hydrogen Substitution by Alkyllithium Reagents (pages 2642–2646)

      Dr. Ali Reza Mohebbi and Prof. Dr. Fred Wudl

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201002608

      Thumbnail image of graphical abstract

      Great potential: New derivatives of dithiarubicene (emeraldicene), which are of potential use as organic acceptors, are reported (see figure, R = -H, -dodecyl, -ethylhexyl). Additionally, nucleophilic aromatic hydrogen displacement alkylation of emeraldicene by alkyllithium reagents produced highly soluble mono-substituted emeraldicene, which crystallized in columnar stacks, with excellent overlap between adjacent molecules in the stack.

    7. Fluorescence

      Starburst Triarylamine Donor–Acceptor–Donor Quadrupolar Derivatives Based on Cyano-Substituted Diphenylaminestyrylbenzene: Tunable Aggregation-Induced Emission Colors and Large Two-Photon Absorption Cross Sections (pages 2647–2655)

      Bing Wang, Dr. Yaochuan Wang, Prof. Dr. Jianli Hua, Yihua Jiang, Jinhai Huang, Prof. Dr. Shixiong Qian and Prof. Dr. He Tian

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201002821

      Thumbnail image of graphical abstract

      Starburst triarylamine: Three new derivatives based on cyano-substituted diphenylamine styrylbenzene (CNDPASB; 1 ac) have been designed and synthesized in a concise and environmentally friendly procedure. Their nano-aggregates suspended in aqueous media emit intense red, orange, or deep yellow light when excited with near-IR light (λex=800 nm) to absorb two photons. The color tuning of these CNDPASB-based compounds can be accomplished by changing the triarylamine donor moiety.

    8. Click Chemistry

      “Click” Immobilization on Alkylated Silicon Substrates: Model for the Study of Surface Bound Antimicrobial Peptides (pages 2656–2665)

      Dr. Yan Li, Dr. Catherine M. Santos, Dr. Amit Kumar, Dr. Meirong Zhao, Analette I. Lopez, Dr. Guoting Qin, Prof. Dr. Alison M. McDermott and Prof. Dr. Chengzhi Cai

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201001533

      Thumbnail image of graphical abstract

      Clicky peptides: Through a combined deprotection/“click” reaction, azido-labeled antimicrobial peptides were site-specifically tethered onto bioinert monolayer platforms presenting various densities of trimethylgermanyl-protected alkynyl groups. The immobilized peptides (see figure) exhibited a remarkable antibacterial activity when their density was above ≈1.6×1013 cm2, while remaining cyto-compatible to mammalian cells.

    9. Phosphorus Compounds

      1,2-Diphosphaacenaphthene 1,2-Dications: Synthetic, Stereochemical and Computational Study of the Stabilising Role of Naphthalene-1,8-diyl Backbone (pages 2666–2677)

      D. M. Upulani K. Somisara, Prof. Dr. Michael Bühl, Dr. Tomas Lebl, Prof. Dr. Neville V. Richardson, Prof. Dr. Alexandra M. Z. Slawin, Prof. Dr. J. Derek Woollins and Dr. Petr Kilian

      Article first published online: 27 JAN 2011 | DOI: 10.1002/chem.201002259

      Thumbnail image of graphical abstract

      Steric clash: Chiral 1,2-diphosphoniums are synthesised efficiently by the double alkylation of a diphosphine (see scheme). A probe into their stereochemistry, as well as a study of their role in the assessment of the energy price of a steric clash in a range of peri-substituted naphthalenes, is presented.

    10. Natural Products

      Total Synthesis and Biological Assessment of (−)-Exiguolide and Analogues (pages 2678–2688)

      Prof. Dr. Haruhiko Fuwa, Dr. Takaya Suzuki, Prof. Dr. Hiroshi Kubo, Dr. Takao Yamori and Prof. Dr. Makoto Sasaki

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201003135

      Thumbnail image of graphical abstract

      Potent activity: An enantioselective total synthesis of (−)-exiguolide (see figure) was achieved for the first time, which allowed for elucidation of its potent antiproliferative activity against several human cancer cell lines.

    11. Trifluoromethylation Reactions

      Copper-Catalyzed Trifluoromethylation of Aryl Iodides with Potassium (Trifluoromethyl)trimethoxyborate (pages 2689–2697)

      Thomas Knauber, Fatih Arikan, Prof. Dr. Gerd-Volker Röschenthaler and Prof. Dr. Lukas J. Gooßen

      Article first published online: 27 JAN 2011 | DOI: 10.1002/chem.201002749

      Thumbnail image of graphical abstract

      Stable reagent: Potassium (trifluoromethyl)trimethoxyborate is introduced as a new source of CF3 nucleophiles in Cu-catalyzed trifluoromethylation reactions. The stable crystalline salt allows the conversion of aryl iodides into the corresponding benzotrifluorides in high yields under mild, base-free conditions in the presence of catalytic quantities of a CuI/1,10-phenanthroline complex (see scheme; FG=functional group).

    12. Chirality Transfer

      Neighboring Lithium-Assisted [1,2]-Wittig Rearrangement: Practical Access to Diarylmethanol-Based 1,4-Diols and Optically Active BINOL Derivatives with Axial and sp3-Central Chirality (pages 2698–2703)

      Guang Gao , Feng-Lei Gu , Prof. Jian-Xiong Jiang, Dr. Kezhi Jiang, Dr. Chun-Qi Sheng, Prof. Guo-Qiao Lai and Prof. Dr. Li-Wen Xu 

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201003111

      Thumbnail image of graphical abstract

      Pass it on: Intramolecular lithium-assisted [1,2]-Wittig rearrangement converts simple ethers into synthetically useful diarylmethanol-based 1,4-diols and axially chiral monoalkylated BINOLs into enantiomerically pure Ar-BINMOLs with axial and sp3-central chirality (see scheme).

    13. Multicomponent Reactions

      Multicomponent Synthesis of Chiral Sulfinimines (pages 2704–2708)

      Dr. Caroline Roe, Dr. Heather Hobbs and Dr. Robert A. Stockman

      Article first published online: 26 JAN 2011 | DOI: 10.1002/chem.201003222

      Thumbnail image of graphical abstract

      All four one: Four-component reactions of oxathiazolodine-S-oxides with Grignard reagents, lithium bis(trimethylsilyl)amide, and aldehydes afford chiral non-racemic sulfinimines in good to excellent yields and high enantiomeric excesses (see scheme).

    14. Ferromagnetic Materials

      Magnetoresistance in La0.5Sr0.5MnO2.5 (pages 2709–2715)

      Dr. Raquel Cortés-Gil, Dr. M. Luisa Ruiz-González, Dr. José M. Alonso, Prof. Mar García-Hernández, Prof. Antonio Hernando, Prof. María Vallet-Regí and Prof. José M. González-Calbet

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201002080

      Thumbnail image of graphical abstract

      The coexistence of Mn2+, Mn3+ and Mn4+ in La0.5Sr0.5MnO2.5 leads to nano-ferromagnetic (FM) clusters in octahedral layers acquiring 2D character inside the 3D AFM brownmillerite structure (see figure). Resistance measurements indicate the presence of magnetoresistance (MR) suggesting a temperature-activated conduction process between FM clusters inside an insulating antiferromagnetic matrix. La0.5Sr0.5MnO2.5 is the first MR brownmillerite material in which both octahedral and tetrahedral layers are occupied by Mn atoms.

    15. Copper Catalysis

      Copper(I)–Anilide Complex [Na(phen)3][Cu(NPh2)2]: An Intermediate in the Copper-Catalyzed N-Arylation of N-Phenylaniline (pages 2716–2723)

      Chia-Kai Tseng, Chi-Rung Lee, Chien-Chung Han and Shin-Guang Shyu

      Article first published online: 26 JAN 2011 | DOI: 10.1002/chem.201002661

      Thumbnail image of graphical abstract

      Trapping intermediates: A copper(I)–anilide complex, [Na(phen)3][Cu(NPh2)2], has been isolated as an intermediate in the copper-catalyzed N-arylation of N-phenylaniline. Both [Cu(NPh2)2] and [Cu(NPh2)I] species have been observed by mass spectrometric analysis under catalytic reaction conditions. A catalytic cycle is proposed (see scheme; phen=1,10-phenanthroline).

    16. Supramolecular Chemistry

      Kinetic Studies Exploring the Role of Anion Templation in the Slippage Formation of Rotaxane-Like Structures (pages 2724–2733)

      Dr. Anna J. McConnell and Prof. Paul D. Beer

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201002528

      Thumbnail image of graphical abstract

      To slip on or off depends on the anion: The first examples of using slippage and anion templation to assemble rotaxane-like structures are described (see scheme). Kinetic investigations reveal that the fastest slippage on rates are achieved with the non-coordinating hexafluorophosphate anion, whereas coordinating anions, such as chloride, thermodynamically stabilise the rotaxane-like species.

    17. Borane Synthesis

      Pd-Catalyzed Borylative Polycyclization of Enediynes to Alkylboronates (pages 2734–2741)

      Dr. Juan Marco-Martínez, Dr. Elena Buñuel, Ruth López-Durán and Prof. Dr. Diego J. Cárdenas

      Article first published online: 30 JAN 2011 | DOI: 10.1002/chem.201001124

      Thumbnail image of graphical abstract

      Tandem cyclization: Pd-catalyzed bicyclization of 1-ene-6,11-diynes with bis(pinacolato)diboron smoothly affords synthetically useful homoallylic alkylboronates under mild conditions, avoiding the use of highly nucleophilic or basic reagents. One C[BOND]B bond and two new C[BOND]C bonds are created, and two new stereogenic centers are stereospecifically formed in a single tandem operation (see scheme).

    18. 2′,4′-BNANC

      2′-O,4′-C-Aminomethylene-Bridged Nucleic Acid Modification with Enhancement of Nuclease Resistance Promotes Pyrimidine Motif Triplex Nucleic Acid Formation at Physiological pH (pages 2742–2751)

      Prof. Hidetaka Torigoe, Dr. S. M. Abdur Rahman, Hiroko Takuma, Norihiro Sato, Prof. Takeshi Imanishi, Prof. Satoshi Obika and Kiyomi Sasaki

      Article first published online: 24 JAN 2011 | DOI: 10.1002/chem.201002745

      Thumbnail image of graphical abstract

      Triple your chemistry! The 2′-O,4′-C-aminomethylene-bridged nucleic acid (2′,4′-BNANC) modification of a single strand to bind with the target double strand to form the triplex (see scheme) increased the binding constant of the triplex formation under physiological conditions by decreasing entropic loss and the dissociation rate constant. The 2′,4′-BNANC modification also increased the nuclease resistance in human serum.

    19. Metalloenzymes

      Copper(I) and Copper(II) Inhibit Aβ Peptides Proteolysis by Insulin-Degrading Enzyme Differently: Implications for Metallostasis Alteration in Alzheimer’s Disease (pages 2752–2762)

      Dr. Giuseppe Grasso, Dr. Adriana Pietropaolo, Prof. Giuseppe Spoto, Dr. Giuseppe Pappalardo, Dr. Grazia Raffaella Tundo, Dr. Chiara Ciaccio, Prof. Massimo Coletta and Prof. Enrico Rizzarelli

      Article first published online: 27 JAN 2011 | DOI: 10.1002/chem.201002809

      Thumbnail image of graphical abstract

      The effect of metal ions on IDE: Metal ions, such as Cu2+, Cu+, and Ag+, have an inhibitory effect on insulin-degrading enzyme (IDE) activity (see figure). The inhibition of copper(II) is reversed by adding zinc(II), whereas the monovalent cations affect the enzyme activity irreversibly. A calyx structure is formed due to a destabilization of the hydrophobic core, occurring when Cys 812 and Cys 819 are blocked with Cu+.

    20. Heterogeneous Catalysis

      Direct Hydrogenation of Nitroaromatics and One-Pot Amidation with Carboxylic Acids over Platinum Nanowires (pages 2763–2768)

      Min Li, Lei Hu, Xueqin Cao, Haiyan Hong, Prof. Dr. Jianmei Lu and Prof. Dr. Hongwei Gu

      Article first published online: 26 JAN 2011 | DOI: 10.1002/chem.201002801

      Thumbnail image of graphical abstract

      Nanocatalysis: The direct hydrogenation of nitroaromatics and the one-pot amidation with carboxylic acids by a ultrathin platinum nanowire in various solvents under mild conditions has been described (see scheme). The nanowire is simple, economical, and environmentally benign, thus resulting in practical advantages for the synthesis of amines and imides.

    21. Helical Structures

      Mirror Helices and Helicity Switch at Surfaces Based on Chiral Triangular-Shape Oligo(phenylene ethynylenes) (pages 2769–2776)

      Fátima Aparicio, Fátima García, Dr. Gustavo Fernández, Dr. Emilio Matesanz and Prof. Dr. Luis Sánchez

      Article first published online: 26 JAN 2011 | DOI: 10.1002/chem.201001596

      Thumbnail image of graphical abstract

      Triple chiral: Chiral triangular-shaped oligo(phenylene ethynylenes) (OPSs) (S)-1 a and (R)-1 b self-assemble into helices of opposite handedness and a helicity switch is noticeable for the case of chiral (S)-2. The interaction between the chiral coil chains conditions the handedness of the helical pitch, the stability of the supramolecular structure and the supramolecular polymerization mechanism of the studied OPEs, being cooperative for (S)-1 a and (R)-1 b and isodesmic for (S)-2 and 3.

    22. Photocatalysis

      Size- and Shape-Dependent Activity of Metal Nanoparticles as Hydrogen-Evolution Catalysts: Mechanistic Insights into Photocatalytic Hydrogen Evolution (pages 2777–2785)

      Dr. Hiroaki Kotani, Ryo Hanazaki, Dr. Kei Ohkubo, Dr. Yusuke Yamada and Prof. Dr. Shunichi Fukuzumi

      Article first published online: 30 JAN 2011 | DOI: 10.1002/chem.201002399

      Thumbnail image of graphical abstract

      Rate of exchange: The catalytic activity of metal nanoparticles (MNPs) of different size and shape is studied based on the rate constant of electron transfer (ket) from one-electron-reduced species of the 9-mesityl-10-methylacridinium ion (Acr+–Mes) to MNPs. The linear dependence of ket on proton concentration and the inverse kinetic isotope effect (KIE) suggest that proton-coupled electron transfer (PCET) from Acr.–Mes to PtNPs is the rate-determining step for catalytic hydrogen evolution (see picture).

  8. Preview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. You have free access to this content
      Preview: Chem. Eur. J. 10/2011 (page 2787)

      Article first published online: 17 FEB 2011 | DOI: 10.1002/chem.201190043

SEARCH

SEARCH BY CITATION