Chemistry - A European Journal

Cover image for Vol. 17 Issue 40

September 26, 2011

Volume 17, Issue 40

Pages 11073–11351

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Minireview
    7. Communications
    8. Full Papers
    9. Preview
    1. Cover Picture: Modifying Cage Structures in Metal–Organic Polyhedral Frameworks for H2 Storage (Chem. Eur. J. 40/2011) (page 11073)

      Yong Yan, Prof. Dr. Alexander J. Blake, Dr. William Lewis, Dr. Sarah A. Barnett, Dr. Anne Dailly, Prof. Dr. Neil R. Champness and Prof. Dr. Martin Schröder

      Article first published online: 16 SEP 2011 | DOI: 10.1002/chem.201190195

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      The synthesis of metal–organic polyhedral framework materials, based upon trigonal hexacarboxylate isophthalate linkers, leads to a strategy that generates highly porous materials with relatively high stability and surface areas. These polyhedral MOFs (NOTT-113, NOTT-114 and NOTT-115) show high H2-adsorption capacities. For more details see the Full Paper on page 11162 ff. by M. Schröder, N. R. Champness et al.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Minireview
    7. Communications
    8. Full Papers
    9. Preview
    1. Inside Cover: Surface-Modified Protein Microspheres Capture Amyloid-β and Inhibit its Aggregation and Toxicity (Chem. Eur. J. 40/2011) (page 11074)

      Michal Richman, Sarah Wilk, Natalia Skirtenko, Dr. Alex Perelman and Dr. Shai Rahimipour

      Article first published online: 16 SEP 2011 | DOI: 10.1002/chem.201190196

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      Accumulation and aggregation of amyloid-β (Aβ) in the brain is the primary pathogenic event in Alzheimer's disease (AD). Thus reducing the level of Aβ in the brain is considered to be a promising strategy for AD therapy. In their Full Paper on page 11171 ff., S. Rahimipour et al. describe sonochemically prepared protein microspheres, the surfaces of which are modified with an Aβ recognition peptide. The microspheres can bind with high affinity and selectivity to Aβ, sequester it from the medium, inhibit its aggregation, and directly reduce its toxicity toward neuron-like cells.

  3. Graphical Abstract

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

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

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

      Cycloaddition Reactions: A Controlled Approach for Carbon Nanotube Functionalization (pages 11092–11101)

      Dr. Indresh Kumar, Dr. Sravendra Rana and Prof. Jae Whan Cho

      Article first published online: 31 AUG 2011 | DOI: 10.1002/chem.201101260

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      Tuning tubes: The functionalization of carbon nanotubes (CNTs) by means of cycloaddition reactions plays an important role in achieving mechanical, electrical, and biological functions and enhancing their dispersion in different matrixes. Through these reactions, an enormous variety of molecules can be coupled onto CNTs in a very controlled manner and they can be exploited to prepare CNT-based hybrid materials for a wide range of applications.

  6. Communications

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

      Spectroscopic Probing of the Dynamic Self-Assembly of an Amphiphilic Naphthalene Diimide Exhibiting Reversible Vapochromism (pages 11102–11106)

      Mohit Kumar and Dr. Subi J. George

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201101642

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      Fluorescent nose: The reversible “turn-on” vapochromism of a self-assembled amphiphilic naphthalene diimide derivative in solution and film states is presented. This property was found to be due to solvent–vapor-responsive, dynamic reorganization in molecular packing in going from J-type aggregates (blue fluorescent; see left-hand side of scheme) to preassociated H-type excimer states, with enhanced green fluorescence.

    2. Protein Structures

      Screw-Sense Control of Helical Oligopeptides Containing Equal Amounts of L- and D-Amino Acids (pages 11107–11109)

      Dr. Yosuke Demizu, Prof. Mitsunobu Doi, Yukiko Sato, Prof. Masakazu Tanaka, Dr. Haruhiro Okuda and Dr. Masaaki Kurihara

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201101809

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      Residue order is important! The preferred secondary structures of Boc-(L-Leu-D-Leu-Aib)n-OMe containing equal amounts of L- and D-Leu have been investigated and the results show that these residues form right-handed (P) α helices in both solution and crystalline states (see picture).

    3. Heterogeneous Catalysis

      Enhancing the Initial Rate of Polymerisation of the Reduced Phillips Catalyst by One Order of Magnitude (pages 11110–11114)

      Dr. Elena Groppo, Dr. Alessandro Damin, Prof. Carlos Otero Arean and Prof. Adriano Zecchina

      Article first published online: 26 AUG 2011 | DOI: 10.1002/chem.201101714

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      Catalyst engineering! Controlled thermal treatment with N2O affords easy active-site engineering of the CrII/SiO2 Phillips catalyst, overcoming some of the structural problems limiting ethylene polymerisation activity and leading to a large increase in the initial rate of polymerisation at room temperature (see figure). The results may be highly relevant to the production of some varieties of polyethylene.

    4. Solar Cells

      A Desirable Hole-Conducting Coadsorbent for Highly Efficient Dye-Sensitized Solar Cells through an Organic Redox Cascade Strategy (pages 11115–11121)

      Dr. Bok Joo Song, Hae Min Song, In Taek Choi, Sang Kyun Kim, Kang Duk Seo, Min Soo Kang, Myung Jun Lee, Dr. Dae Won Cho, Dr. Myung Jong Ju and Prof. Hwan Kyu Kim

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201100813

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      Under the sun! A new low-molecular-weight and multiple-functional coadsorbent (HC-A) for highly efficient dye-sensitized solar cells has been developed. The NKX2677/HC-A-sensitized solar cell exhibited remarkably enhanced conversion efficiency by a factor of 1.33 compared to the NKX2677 dye-sensitized solar cell under standard test conditions.

    5. Soft Materials

      Nonvolatile RTIL-Based Artificial Muscle: Actuation Mechanism Identified by In Situ EDX Analysis (pages 11122–11126)

      Prof. Tetsuya Tsuda, Masahiro Baba, Yuichi Sato, Rentaro Sakao, Prof. Kazuhiko Matsumoto, Prof. Rika Hagiwara and Prof. Susumu Kuwabata

      Article first published online: 26 AUG 2011 | DOI: 10.1002/chem.201101240

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      Muscling in: The nonvolatility of a room-temperature ionic liquid (RTIL)–PVdF–HFP composite-material-based artificial muscle, prepared in this study, enabled the measurement of in situ electrochemical energy dispersive X-ray (EDX) spectroscopy of the device. A bending model that strongly depends on the ionic transport number is proposed from the in situ EDX analysis.

    6. Asymmetric Catalysis

      Enantioselective and Regioselective Friedel–Crafts Alkylation of Pyrroles with Nitroalkenes Catalyzed by a Tridentate Schiff Base–Copper Complex (pages 11127–11130)

      Fengfeng Guo, Dalu Chang, Guoyin Lai, Tao Zhu, Shunshun Xiong, Dr. Sujing Wang and Prof. Dr. Zhiyong Wang

      Article first published online: 31 AUG 2011 | DOI: 10.1002/chem.201102206

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      On a (pyr)role: A mild and highly efficient catalytic system has been developed for the asymmetric Friedel–Crafts alkylation of pyrroles with nitroalkenes (see scheme). High yields, and excellent enantioselectivities and regioselectivities were obtained for a broad range of substrates. The synthetic utility of this methodology and mechanistic studies involving a novel, negative, nonlinear effect are also presented.

    7. Cycloadditions

      The Catalytic Asymmetric Diels–Alder Reactions and Post-cycloaddition Reductive Transpositions of 1-Hydrazinodienes (pages 11131–11134)

      Dr. Hao Xie, Dr. Glenn M. Sammis, Dr. Eric M. Flamme, Christina M. Kraml and Prof. Dr. Erik J. Sorensen

      Article first published online: 5 SEP 2011 | DOI: 10.1002/chem.201102394

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      Cycling through: Type I cyclohexenes are produced with high margins of stereoselectivity by chiral, catalyst-controlled, Diels–Alder reactions between 1-hydrazinodienes and N-acryloyl oxazolidinone dienophiles, and readily transformed to cyclohexenes III via a putative, transient allylic diazene II (see scheme). This chemistry gives access to functionalized cyclohexenes that can be difficult to construct by alternative methods.

    8. Synthetic Methods

      Carbogallation of Alkynes Using Gallium Tribromide and Silyl Ketene Acetals and Synthetic Application to Cross-Coupling with Aryl Iodides (pages 11135–11138)

      Dr. Yoshihiro Nishimoto, Hiroki Ueda, Dr. Makoto Yasuda and Prof. Dr. Akio Baba

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201102255

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      Try substituted alkynes with GaBr3: The regio- and stereoselective carbogallation of alkynes has been achieved by a simple treatment of GaBr3, alkynes, and ketene silyl acetals. The produced alkenylgallium compounds can be used for the synthesis of selective trisubstituted alkenes through successive cross-coupling with aryliodides (see scheme). The usability of the carbogallation was presented by the total synthesis of meroterpenoid nodosol, which was extracted from the seagrass Cymodocea nodosa.

    9. Chiral Amplification

      Chiral Amplification in Crystallization under Ultrasound Radiation (pages 11139–11142)

      Dr. Dana D. Medina, Prof. Aharon Gedanken and Prof. Yitzhak Mastai

      Article first published online: 25 AUG 2011 | DOI: 10.1002/chem.201101221

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      Ultrasonic waves applied during the crystallization of slightly enantiomeric-enriched, supersaturated, aqueous solutions of dl-threonine lead to strong chiral amplifications (up to 90 % ee), particularly at the first stages of the crystallization process (see figure). The findings are confirmed by the optical rotation and circular-dichroism experiments of the crystallization solutions.

    10. Isomerization

      Highly Enantioselective Asymmetric Isomerization of Primary Allylic Alcohols with an Iridium–N,P Complex (pages 11143–11145)

      Jia-Qi Li, Byron Peters and Prof. Dr. Pher G. Andersson

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201101524

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      Access to chiral aldehydes: The asymmetric isomerization of primary allylic alcohols was studied with a bicyclic phosphine-oxazoline iridium catalyst. This method displays a broad substrate scope and leads to the desired chiral aldehydes with excellent enantioselectivities (see scheme; R1, R2=Ar or alkyl).

    11. Cross-Coupling

      CuI/H2/NaOH-Catalyzed Cross-Coupling of Two Different Alcohols for Carbon–Carbon Bond Formation: “Borrowing Hydrogen”? (pages 11146–11151)

      Takashi Miura, Osamu Kose, Dr. Feng Li, Dr. Sun Kai and Dr. Susumu Saito

      Article first published online: 31 AUG 2011 | DOI: 10.1002/chem.201101752

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      Not borrowed: A new method was developed for the cross-coupling of two different alcohols (see scheme). This carbon–carbon bond formation was realized by using a small amount of CuBr (0.05–0.2 mol %) and NaOH (4–20 mol %) in the presence of H2 (1 atm), and provides an alternative procedure for longer-chain alcohols. The catalytic cycle was different from those reported to date for the Guerbet reaction involving “borrowing hydrogen”.

  7. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Minireview
    7. Communications
    8. Full Papers
    9. Preview
    1. Vis–NIR/Fluorescent Sensor

      Visible–Near-Infrared and Fluorescent Copper Sensors Based on Julolidine Conjugates: Selective Detection and Fluorescence Imaging in Living Cells (pages 11152–11161)

      Debabrata Maity, Arun K. Manna, D. Karthigeyan, Prof. Tapas K. Kundu, Prof. Swapan K. Pati and Dr. T. Govindaraju

      Article first published online: 1 SEP 2011 | DOI: 10.1002/chem.201101906

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      Seeing is believing: The julolidine–carbonohydrazone and julolidine–thiocarbonohydrazone ligands detect Cu2+ colorimetrically with characteristic absorbance in the near-infrared (NIR, 700–1000 nm) region, which allows the detection of different concentrations of Cu2+ by the naked eye due to the appearance of distinct coloration. Fluorescent julolidine–thiocarbonohydrazone reversibly senses intracellular Cu2+ in cultured HEK293T cells (see figure).

    2. Hydrogen Storage

      Modifying Cage Structures in Metal–Organic Polyhedral Frameworks for H2 Storage (pages 11162–11170)

      Yong Yan, Prof. Dr. Alexander J. Blake, Dr. William Lewis, Dr. Sarah A. Barnett, Dr. Anne Dailly, Prof. Dr. Neil R. Champness and Prof. Dr. Martin Schröder

      Article first published online: 6 SEP 2011 | DOI: 10.1002/chem.201101341

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      Linked in! Trimethylphenyl, phenylamine and triphenylamine linkers have been incorporated into isostructural (3,24)-connected polyhedral metal–organic frameworks (denoted NOTT-113, NOTT-114 and NOTT-115, shown here from left to right) by combining hexacarboxylate isophthalate linkers with {Cu2(RCOO)4} paddlewheels. The effects of these groups on N2 and H2 uptakes in the resultant porous materials are reported.

    3. Drug Delivery

      Surface-Modified Protein Microspheres Capture Amyloid-β and Inhibit its Aggregation and Toxicity (pages 11171–11177)

      Michal Richman, Sarah Wilk, Natalia Skirtenko, Dr. Alex Perelman and Dr. Shai Rahimipour

      Article first published online: 2 SEP 2011 | DOI: 10.1002/chem.201101326

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      Undercover agent: An easy, one-pot, sonochemical approach for the synthesis of protein microspheres decorated with an amyloid-β (Aβ) recognition peptide is described (see scheme). The microspheres bind with high affinity and selectivity to Aβ, the main pathogenic protein in Alzheimer's disease, then sequester it from the medium and directly block its aggregation. Incubation of the cells with microspheres significantly reduced the Aβ-induced toxicity.

    4. Porphyrinoids

      New Perspectives on Iron–Ligand Vibrations of Oxyheme Complexes (pages 11178–11185)

      Dr. Jianfeng Li, Dr. Qian Peng, Dr. Alexander Barabanschikov, Jeffrey W. Pavlik, Dr. E. Ercan Alp, Dr. Wolfgang Sturhahn, Dr. Jiyong Zhao, Prof. Charles E. Schulz, Prof. J. Timothy Sage and Prof. W. Robert Scheidt

      Article first published online: 29 AUG 2011 | DOI: 10.1002/chem.201101352

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      Powder and oriented single-crystal nuclear resonance vibrational spectroscopy studies of iron porphyrinate dioxygen complexes with three different imidazole ligands reveal new Fe–ligand vibrations, including the long-sought Fe–Im stretch.

    5. Crystallization

      Size-Dependent Phase Stability of a Molecular Nanocrystal: a Proxy for Investigating the Early Stages of Crystallization (pages 11186–11192)

      Prof. Dr. Dirk Zahn and Prof. Jamshed Anwar

      Article first published online: 25 AUG 2011 | DOI: 10.1002/chem.201100710

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      Phased with a barrier: Simulations on nanocrystals as proxies for nuclei show that barriers to successive transformations during the earliest stages of crystallization (Ostwald's rule) arise from higher surface-area transition states of the emerging crystalline units (see figure).

    6. Cryptands

      A Trinuclear Copper(II) Cryptate and Its μ3-CO3 Cascade Complex: Thermodynamics, Structural and Magnetic Properties (pages 11193–11203)

      Pedro Mateus, Prof. Rita Delgado, Prof. Francesc Lloret, Dr. Joan Cano, Dr. Paula Brandão and Prof. Vítor Félix

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201101372

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      A bicycle made for CO2: The studied trinuclear CuII cryptate absorbs atmospheric CO2 at slightly acidic pH, to form a μ3-CO3 cascade complex (see structure). This represents the first μ3-CO3-bridged trinuclear copper(II) complex located in the interior of a macrobicyclic cavity. The macrobicyclic architecture of the ligand is responsible for the interesting properties observed.

    7. Protein–Carbohydrate Interactions

      Conformational Selection of the AGA*IAM Heparin Pentasaccharide when Bound to the Fibroblast Growth Factor Receptor (pages 11204–11209)

      Lidia Nieto, Dr. Ángeles Canales, Prof. Guillermo Giménez-Gallego, Dr. Pedro M. Nieto and Prof. Jesús Jiménez-Barbero

      Article first published online: 25 AUG 2011 | DOI: 10.1002/chem.201101000

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      Conformational selectivity! The interaction of the synthetic heparin pentasaccharide AGA*IAM (GlcNS,6S-GlcA-GlcNS,3S,6S-IdoA2S-GlcNS,6S-Me) with the extracellular Ig2 domain of the fibroblast growth factor receptor (FGFR2; see figure) has been studied by NMR and computational methods. Analysis of the heparin pentasaccharide in the free state and in the complex indicates the existence of a conformational selection process.

    8. Cancer Detection

      Simultaneous Detection of Intracellular Tumor mRNA with Bi-Color Imaging Based on a Gold Nanoparticle/Molecular Beacon (pages 11210–11215)

      Guangming Qiao, Yuan Gao, Na Li, Zhengze Yu, Linhai Zhuo and Prof. Bo Tang

      Article first published online: 17 AUG 2011 | DOI: 10.1002/chem.201100658

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      Twice as much: A gold nanoparticle was assembled with a molecular beacon to prepare a bi-color fluorescence imaging agent (see scheme) for the simultaneous detection of two types of intracellular tumor mRNA in breast cancer cells. This novel approach could prevent “false positive” results, enable real-time detection of the relative expression levels of tumor mRNA in cancer cells, and allow the early detection of cancer, unlike single tumor mRNA testing.

    9. Ruthenium Catalysis

      Tuning of the Electronic Properties of a Cyclopentadienylruthenium Catalyst to Match Racemization of Electron-Rich and Electron-Deficient Alcohols (pages 11216–11222)

      Oscar Verho, Eric V. Johnston, Erik Karlsson and Jan-E. Bäckvall

      Article first published online: 31 AUG 2011 | DOI: 10.1002/chem.201100827

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      Finely tuned: Progress has been made in the development of racemization catalysts for secondary alcohols. By tuning the catalyst to match the electronic properties of the substrate, highly efficient racemization protocols for alcohols with varying electronic properties were achieved (see scheme).

    10. Microcapsules

      Rose Bengal-Grafted Biodegradable Microcapsules: Singlet-Oxygen Generation and Cancer-Cell Incapacitation (pages 11223–11229)

      Xiao-Lei Wang, Yu Zeng, Dr. Yan-Zhen Zheng, Prof. Dr. Jian-Feng Chen, Prof. Dr. Xia Tao, Ling-Xuan Wang and Yan Teng

      Article first published online: 18 AUG 2011 | DOI: 10.1002/chem.201100975

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      Seen in a rosy light: Rose bengal (RB)-grafted biodegradable microcapsules, an effective vehicle for singlet-oxygen generation and cancer-cell incapacitation, were fabricated by a core-mediated layer-by-layer technique, in which RB-grafted chitosan (RB-CHI) was coated onto the outer layer of preformed biodegradable microcapsules, consisting of sodium alginate (ALG) and CHI. RB-CHI served as a photosensitive capsule coating (see picture).

    11. Nanoparticle DNA Probes

      Dynamic-Light-Scattering-Based Sequence-Specific Recognition of Double-Stranded DNA with Oligonucleotide-Functionalized Gold Nanoparticles (pages 11230–11236)

      Xiang-Min Miao, Cen Xiong, Wei-Wei Wang, Prof. Dr. Lian-Sheng Ling and Prof. Dr. Xin-Tao Shuai

      Article first published online: 26 AUG 2011 | DOI: 10.1002/chem.201003010

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      Size counts: An ultrasensitive and simple dynamic-light-scattering (DLS) assay for the sequence-specific recognition of double-stranded DNA (dsDNA) was developed based on detection of the average diameter change of oligonucleotide-modified gold-nanoparticle (AuNP) probes (see figure).

    12. Phase Transitions

      Photochemical Switching of the Phase-Transition Temperatures of p-NIPAM–Pt Nanoparticles Thermosensitive Polymer Composites Associated with Electrodes: Functional Electrodes for Switchable Electrocatalysis (pages 11237–11242)

      Junji Zhang, Dr. Michael Riskin, Dr. Ran Tel-Vered, Prof. He Tian and Prof. Itamar Willner

      Article first published online: 25 AUG 2011 | DOI: 10.1002/chem.201100714

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      Photoswitchable electrocatalysis proceeds in the presence of a photoisomerizable thermosensitive polymer that includes Pt nanoparticles (see figure). The electrocatalysis is active in the presence of the nitromerocyanine-functionalized poly(N-isopropylacrylamide) (p-NIPAM), but is inhibited in the presence of the nitrospiropyran-modified p-NIPAM, as a consequence of material phase and permeability.

    13. Asymmetric Catalysis

      Enantioselective and Diastereoselective Tsuji–Trost Allylic Alkylation of Lactones: An Experimental and Computational Study (pages 11243–11249)

      Dr. Panos Meletis, Dr. Mahendra Patil, Prof. Dr. Walter Thiel, Prof. Dr. Walter Frank and Prof. Dr. Manfred Braun

      Article first published online: 26 AUG 2011 | DOI: 10.1002/chem.201101406

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      Lithium enolates and palladium: Stereoselective, palladium-catalyzed, allylic alkylation has been extended to the lithium enolates of γ- and δ-lactones. A computational study favors a mechanism wherein lithium chloride plays a key role as the connecting link between the noble metal and the enolate (see figure). The observed stereoselectivity agrees with the results of the theoretical calculations.

    14. Hydroxylamines

      1,2-Dihydrotriazinyl-N-oxy Free Radicals (pages 11250–11257)

      Dr. Peter Brough, Dr. Serge Gambarelli, Jean-François Jacquot, Dr. André Grand, Dr. Jacques Pécaut and Dr. Paul Rey

      Article first published online: 18 AUG 2011 | DOI: 10.1002/chem.201100433

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      New organic spin carriers: Nitroxide free radicals derived from 1,3,5-triazines, in which the unpaired electron is delocalized over three potential coordination sites, have been prepared and characterized (see figure).

    15. Structure Elucidation

      SrP3N5O: A Highly Condensed Layer Phosphate Structure Solved from a Nanocrystal by Automated Electron Diffraction Tomography (pages 11258–11265)

      Stefan J. Sedlmaier, Dr. Enrico Mugnaioli, Dr. Oliver Oeckler, Dr. Ute Kolb and Prof. Dr. Wolfgang Schnick

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201101545

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      Most valuable layer: By applying automated electron diffraction tomography (ADT), an exceptional phosphate structure has been discovered in SrP3N5O (see figure). The structure comprises Sr2+ ions and corrugated equation image{P3N5O)2−} layers composed of linked, triangular columns that are built up from P(O,N)4 tetrahedra with 3-rings and triply binding nitrogen atoms involved.

    16. Metal–Metal Bonds

      The Nature of Unsupported Uranium–Ruthenium Bonds: A Combined Experimental and Theoretical Study (pages 11266–11273)

      Benedict M. Gardner, Dr. Dipti Patel, Andrew D. Cornish, Dr. Jonathan McMaster, Dr. William Lewis, Prof. Alexander J. Blake and Dr. Stephen T. Liddle

      Article first published online: 26 AUG 2011 | DOI: 10.1002/chem.201101394

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      Support for unsupported U[BOND]Ru bonds: The first structurally characterized examples of uranium–ruthenium bonds are reported. Detailed DFT calculations, energy decomposition, and topological analysis of the electron density in the uranium–ruthenium bonds reveals closed-shell interactions with a predominantly ionic interaction.

    17. Silanone Complexes

      From a Stable Silanone Complex to Isolable, Donor-Supported Silicoxonium Halides [LSi(dmap)[DOUBLE BOND]O[BOND]SiMe3]+X (pages 11274–11279)

      Dr. Yun Xiong, Dr. Shenglai Yao, Dr. Elisabeth Irran and Prof. Dr. Matthias Driess

      Article first published online: 25 AUG 2011 | DOI: 10.1002/chem.201101610

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      Take five: The first Lewis base stabilized, silylated, silicoxonium bromide 3 and iodide 5 have been isolated from the reaction of p-dimethylaminopyridine (dmap)–silanone complex 1 with respective trimethylsilyl halides. Compound 5 is stable both in the solid state and in solutions; whereas, compound 3 liberates the dmap molecule in THF to yield the Si[DOUBLE BOND]O addition product 4.

    18. Metallopolymers

      Metallopolymers Featuring Boratabenzene Iron Complexes (pages 11280–11289)

      Dr. Frank Pammer, Prof. Roger A. Lalancette and Prof. Frieder Jäkle

      Article first published online: 26 AUG 2011 | DOI: 10.1002/chem.201101109

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      New bis(borinato)iron complexes have been prepared and spectroscopically, structurally, and electrochemically characterized. 1,1′-Bis(ethynylborinato)iron(II) (see scheme) was successfully employed in polymer syntheses through Sonogashira–Hagihara coupling and click polymerization.

    19. Organophosphorus Catalysis

      In Situ Phosphine Oxide Reduction: A Catalytic Appel Reaction (pages 11290–11295)

      Henri A. van Kalkeren, Stefan H. A. M. Leenders, C. Rianne A. Hommersom, Prof. Dr. Floris P. J. T. Rutjes and Dr. Floris L. van Delft

      Article first published online: 25 AUG 2011 | DOI: 10.1002/chem.201101563

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      Phosphole regeneration by in situ reduction of phosphole oxides was used as the basis for the development of a catalytic Appel reaction (see scheme), which transforms alcohols into bromides and chlorides with good conversions.

    20. Kinetic Resolution

      Kinetic Resolution of α-Substituted Alkanoic Acids Promoted by Homobenzotetramisole (pages 11296–11304)

      Xing Yang and Prof. Vladimir B. Birman

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201101028

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      Structurally simple acyl-transfer catalyst homobenzotetramisole (HBTM) promotes effective kinetic resolution of a variety of α-substituted alkanoic acids via enantioselective alcoholysis of intermediate anhydrides. In the case of α-(aryl/alkylthio)alkanoic acids, the reaction is accompanied by in situ racemization giving rise to dynamic kinetic resolution (see scheme).

    21. Polysaccharides

      Systematic Synthesis of Inhibitors of the Two First Enzymes of the Bacterial Heptose Biosynthetic Pathway: Towards Antivirulence Molecules Targeting Lipopolysaccharide Biosynthesis (pages 11305–11313)

      Dr. Maxime Durka, Dr. Abdellatif Tikad, Dr. Régis Périon, Dr. Michael Bosco, Dr. Mounir Andaloussi, Stéphanie Floquet, Elodie Malacain, Dr. François Moreau, Dr. Mayalen Oxoby, Dr. Vincent Gerusz and Prof. Stéphane P. Vincent

      Article first published online: 26 AUG 2011 | DOI: 10.1002/chem.201100396

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      Sugar key: D-glycero-D-manno-Heptopyranose 7-phosphate (H7P) is a key precursor of the bacterial lipopolysaccharide (LPS), a cell-wall glycolipid implied in the virulence of many human pathogens. A series of H7P analogues modified at the 1-, 2-, 6- and 7-positions of the heptose scaffold have been synthesized and assayed against GmhA and HldE, the two first enzymes of the bacterial heptose biosynthesis.

    22. Nanoparticles

      Size-Controllable Gold–Platinum Alloy Nanoparticles on Nine Functionalized Ionic-Liquid Surfaces and Their Application as Electrocatalysts for Hydrogen Peroxide Reduction (pages 11314–11323)

      Yanyan Yu, Qian Sun, Xiaoqian Liu, Haihong Wu, Tianshu Zhou and Prof. Guoyue Shi

      Article first published online: 18 AUG 2011 | DOI: 10.1002/chem.201100010

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      Functionalized ionic-liquid surfaces: A facile way to fabricate size-controllable nanoparticles using functionalized room-temperature ionic liquids (RTILs) is reported (see figure). The electrocatalytic activities of the RTIL–Au/Pt nanocomposites can also be tuned by employing RTILs with different functional groups, and an appropriate combination of cations and anions can produce a higher activity toward H2O2.

    23. Conducting Materials

      Mixed Conductivity, Nonstoichiometric Oxygen, and Oxygen Permeation Properties in Co-Doped Sr3Ti2O7−δ (pages 11324–11331)

      Dr. Sirikanda Nuansaeng, Prof. Dr. Masatomo Yashima, Dr. Maki Matsuka and Prof. Dr. Tatsumi Ishihara

      Article first published online: 17 AUG 2011 | DOI: 10.1002/chem.201003644

      Thumbnail image of graphical abstract

      Oxygen permeation in Sr3Ti2O7−δ: Doping of Sr3Ti2O7−δ with Co was found to improve the oxide-ion conduction, resulting in an increase in the oxygen-permeation properties. Neutron diffraction analysis suggests that the oxygen diffusion occurs through oxygen vacancy in the perovskite block, but not through the rock salt block (see figure). The oxygen-permeation rate reached 2.02 cc min−1 cm−2 at 1273 K for the Sr3Ti0.8Co1.2O7−δ oxide.

    24. Carbaporphyrinoids

      Factors That Regulate the Conformation of m-Benziporphodimethene Complexes: Agostic Metal–Arene Interaction, Hydrogen Bonding, and η2,π Coordination (pages 11332–11343)

      Gao-Fong Chang, Chun-Hung Wang, Hung-Chieh Lu, Dr. Lou-Sing Kan, Dr. Ito Chao, Wei Hao Chen, Dr. Anil Kumar, Dr. Liyang Lo, Mira Anne C. dela Rosa and Dr. Chen-Hsiung Hung

      Article first published online: 23 AUG 2011 | DOI: 10.1002/chem.201100780

      Thumbnail image of graphical abstract

      Weak but influential: Weak interactions play an important role in the conformation of benziporphodimethene complexes. An agostic interaction between C(22)[BOND]H(22) and the metal ion in tetramethyl-m-benziporphodimethene complexes has been confirmed by various studies. Temperature- and solvent-dependent syn/anti ratio change was rationalized by axial chloride exchange and confirmed through chloride-ion titration studies (see graphic).

    25. Sesnors

      Visual Scanometric Detection of DNA through Silver Enhancement Regulated by Gold-Nanoparticle Aggregation with a Molecular Beacon as the Trigger (pages 11344–11349)

      Hanxu Ji, Haifeng Dong, Feng Yan, Dr. Jianping Lei, Dr. Ling Ding, Wenchao Gao and Prof. Huangxian Ju

      Article first published online: 17 AUG 2011 | DOI: 10.1002/chem.201100563

      Thumbnail image of graphical abstract

      A convenient and label-free scanometric approach for DNA assays was designed by integrating a Hg2+-mediated, conformational, molecular beacon and a silver-signal amplification regulated by gold-nanoparticle (AuNP) aggregation. This method provides an efficient platform for a specific visual assay of DNA hybridization (see picture).

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      Preview: Chem. Eur. J. 41/2011 (page 11351)

      Article first published online: 16 SEP 2011 | DOI: 10.1002/chem.201190199

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