Chemistry - A European Journal

Cover image for Vol. 15 Issue 25

June 15, 2009

Volume 15, Issue 25

Pages 6083–6295

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Communications
    6. Full Papers
    7. Preview
    1. Cover Picture: Switchable Ambient-Temperature Singlet–Triplet Dual Emission in Nonconjugated Donor–Acceptor Triarylboron–PtII Complexes (Chem. Eur. J. 25/2009) (page 6083)

      Zachary M. Hudson, Shu-Bin Zhao, Rui-Yao Wang and Suning Wang

      Version of Record online: 5 JUN 2009 | DOI: 10.1002/chem.200990091

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      Singlet–triplet dual emission has been achieved in single molecules containing triarylboron and N-(2′-pyridyl)-7-azaindole chromophores. The structure of a Pt(II) complex and its dual emission spectrum are depicted in the cover picture. In their Full Paper on page 6131 ff., S. Wang et al. demonstrate that metal chelation and nonconjugated chromophores with a common excitation wavelength facilitate singlet and triplet dual emission in solution at ambient temperature that originate from two separate parts of the molecule.

  2. Graphical Abstract

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

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

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Communications
    6. Full Papers
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    1. Multicomponent Reactions

      A Multicomponent Reaction Towards N-(Cyanomethyl)amides (pages 6096–6099)

      Niels Elders, Eelco Ruijter, Frans J. J. de Kanter, Elwin Janssen, Martin Lutz, Anthony L. Spek and Romano V. A. Orru

      Version of Record online: 21 MAY 2009 | DOI: 10.1002/chem.200900785

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      Diversity-oriented synthesis: The multicomponent reaction of α-isocyano amides, aldehydes or ketones, and amines affords N-(cyanomethyl)amides, presenting the fourth class of products from this combination of reagents (see scheme). The scope of the reaction is very broad and various functional groups are tolerated. The outcome of the reaction can also be directed to the formation of 2H-2-imidazolines by AgI catalysis.

    2. Reactive Species

      First Isolation and Spectroscopic Observation of Thiofulminic acid (HCNS) (pages 6100–6102)

      Tibor Pasinszki, Melinda Krebsz, Gábor Bazsó and György Tarczay

      Version of Record online: 15 MAY 2009 | DOI: 10.1002/chem.200900408

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      For the first time: Thiofulminic acid (HCNS), the parent member of the nitrile sulfide family of reactive intermediates and potential interstellar species, was produced and characterized by IR spectroscopy for the first time. HCNS was generated in cryogenic matrices by 254 nm UV irradiation of 1,2,5-thiadiazole (see figure).

    3. Sensors

      A Near-Infrared Fluorescence-Based Optical Thermosensor (pages 6103–6106)

      Seung-Young Lee, Seulki Lee, In-Chan Youn, Dong Kee Yi, Yong Taik Lim, Bong Hyun Chung, James F. Leary, Ick Chan Kwon, Kwangmeyung Kim and Kuiwon Choi

      Version of Record online: 13 MAY 2009 | DOI: 10.1002/chem.200900683

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      A polymeric thermosensor composed of the thermo-responsive block copolymer Pluronic F127 (PF127) and the near-infrared (NIR) dye Cy5.5 can simply monitor, image, and analyze temperature changes. The thermoprobe exhibited linear NIR fluorescent emission changes (see figure) over a broad temperature range (0–80 °C).

    4. Star Polymers

      High-Yield Synthesis of Uniform Star Polymers—Is Controlled Radical Polymerization Always Needed? (pages 6107–6111)

      Haifeng Gao and Krzysztof Matyjaszewski

      Version of Record online: 14 MAY 2009 | DOI: 10.1002/chem.200900680

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      Star formation: A novel and easy method is reported for the synthesis of well-defined star polymers with high star yield by applying conventional radical copolymerization of linear macromonomer and divinyl cross-linkers in a homogeneous solution (see figure).

    5. Density Functional Calculations

      The Steric Nature of the Bite Angle (pages 6112–6115)

      Willem-Jan van Zeist, Ruud Visser and F. Matthias Bickelhaupt

      Version of Record online: 21 MAY 2009 | DOI: 10.1002/chem.200900367

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      Twisted! We show, based on DFT analyses, that the well-known dependence of a catalyst's activity in bond activation on the ligand–metal–ligand angle, or bite angle, has a primarily steric origin, not an electronic one. Thus, by bending or twisting the catalyst a priori, one avoids unfavorable nonbonded interactions with the substrate (see figure).

    6. Graphene Oxide

      Controlled Synthesis of Large-Area and Patterned Electrochemically Reduced Graphene Oxide Films (pages 6116–6120)

      Ming Zhou, Yuling Wang, Yueming Zhai, Junfeng Zhai, Wen Ren, Fuan Wang and Shaojun Dong

      Version of Record online: 14 MAY 2009 | DOI: 10.1002/chem.200900596

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      Have you seen the film? Coupling a spray-coating technique with a facile, low-cost, efficient and environmentally friendly electrochemical method may realize the controllable synthesis of large-area and patterned electrochemically reduced graphene oxide films on various conductive and insulating substrates with thicknesses ranging from a single monolayer to several microns (see figure).

  5. Full Papers

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Communications
    6. Full Papers
    7. Preview
    1. Spin-Crossover Nanoparticles

      Nanoparticles of [Fe(NH2-trz)3]Br2⋅3 H2O (NH2-trz=2-Amino-1,2,4-triazole) Prepared by the Reverse Micelle Technique: Influence of Particle and Coherent Domain Sizes on Spin-Crossover Properties (pages 6122–6130)

      Thibaut Forestier, Abdellah Kaiba, Stanislav Pechev, Dominique Denux, Philippe Guionneau, Céline Etrillard, Nathalie Daro, Eric Freysz and Jean-François Létard

      Version of Record online: 5 JUN 2009 | DOI: 10.1002/chem.200900297

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      By changing the surfactant/water ratio, nanoparticles of the iron(II) spin crossover material, [Fe(NH2-trz)3]Br23 H2O (with NH2-trz=4-amino-1,2,4-triazole), have been synthesised from 1 μm down to 30 nm (see figure). Magnetic and reflectivity experiments indicate that the critical size for observing a thermal hysteresis in this 1D polymer family is around 50 nm, and powder X-ray diffraction shows that particles of about 30 nm are constituted by about one coherent domain.

    2. Dual Emission

      Switchable Ambient-Temperature Singlet–Triplet Dual Emission in Nonconjugated Donor–Acceptor Triarylboron–PtII Complexes (pages 6131–6137)

      Zachary M. Hudson, Shu-Bin Zhao, Rui-Yao Wang and Suning Wang

      Version of Record online: 26 MAY 2009 | DOI: 10.1002/chem.200900641

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      Double the fun! Singlet–triplet dual emission at ambient temperature has been achieved in compounds containing a triarylboron acceptor and an N-(2′-pyridyl)-7-azaindolyl donor group bridged by a tetrahedral Si linker (see figure). PtII chelation and chelate-mode switching from N,N to N,C have been found to greatly enhance phosphorescent emission. Furthermore, both singlet and triplet emission bands are responsive to fluoride ions.

    3. Systems Chemistry

      Interplay of Interactions Governing the Dynamic Conversions of Acyclic and Macrocyclic Helicates (pages 6138–6142)

      Victoria E. Campbell, Xavier de Hatten, Nicolas Delsuc, Brice Kauffmann, Ivan Huc and Jonathan R. Nitschke

      Version of Record online: 14 MAY 2009 | DOI: 10.1002/chem.200900693

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      Systemic change: A system of transformations between helical structures was observed to be governed by interactions mediated by the electronic effects of substituents, entropic effects, the conformational preferences of organic building blocks, and the coordinative preferences of the metal ion. All of these effects were important, but all must be considered together to allow the prediction of the product observed (see scheme).

    4. Host–Guest Chemistry

      Complexation of Aliphatic Ammonium Ions with a Water-Soluble Cucurbit[6]uril Derivative in Pure Water: Isothermal Calorimetric, NMR, and X-ray Crystallographic Study (pages 6143–6151)

      Youngkook Kim, Hyunuk Kim, Young Ho Ko, Narayanan Selvapalam, Mikhail V. Rekharsky, Yoshihisa Inoue and Kimoon Kim

      Version of Record online: 6 MAY 2009 | DOI: 10.1002/chem.200900305

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      Without interference: The complexation of aliphatic ammonium ions with a water-soluble cucurbit[6]uril (CB[6]) derivative, CB*[6] (see picture), in pure water is investigated by isothermal titration calorimetry, NMR spectroscopy, and X-ray crystallography. The binding affinity of the host in pure water is 2–5 orders of magnitude higher than that in the presence of interfering ions, such as protons and alkali metal ions.

    5. Calixarene Fluorescence

      Cooperative Recognition of a Copper Cation and Anion by a Calix[4]arene Substituted at the Lower Rim by a β-Amino-α,β-Unsaturated Ketone (pages 6152–6160)

      Annamalai Senthilvelan, I.-Ting Ho, Kai-Chi Chang, Gene-Hsiang Lee, Yi-Hung Liu and Wen-Sheng Chung

      Version of Record online: 15 MAY 2009 | DOI: 10.1002/chem.200802654

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      Chemodosimeter: Upon titration with CuII, the fluorescence of 1 showed strong fluorescence enhancement because the metal ion helps to lock the conformation of the fluorophores. CuII was reduced to CuI by the free phenolic OH group of 1, the phenol was then oxidised by CuII and assisted in the trapping of CuI. Ditopic behaviour was observed for 1⋅CuI, which showed further enhancement of its fluorescence intensity upon complexation with anions (as depicted, A=CH3COO or F).

    6. Nitrogen Monoxide

      Intermediates in the Autoxidation of Nitrogen Monoxide (pages 6161–6168)

      Benedikt Galliker, Reinhard Kissner, Thomas Nauser and Willem H. Koppenol

      Version of Record online: 12 MAY 2009 | DOI: 10.1002/chem.200801819

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      ONOO. is an important intermediate in the autoxidation of nitrogen monoxide by dioxygen. A formerly unknown red isomer of N2O4, ONOONO (see figure), formed in 2-methylbutane at 113 K from nitrogen monoxide and dioxygen, is converted to O2NNO2 upon warming.

    7. Lithium Batteries

      Porous Co3O4 Nanosheets with Extraordinarily High Discharge Capacity for Lithium Batteries (pages 6169–6174)

      Fangming Zhan, Baoyou Geng and Yijun Guo

      Version of Record online: 12 MAY 2009 | DOI: 10.1002/chem.200802561

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      Cobalt and battery charge: Porous Co3O4 with a hexagonal sheetlike structure has been synthesized through precursor Co(OH)2 hexagonal nanosheets (see figure). The as-prepared nanosheets exhibit excellent Li-battery performance with a good cycle life and high capacity (1450 mAh g−1).

    8. Optical Properties

      Second-Order Nonlinear Optical Activity of Dipolar Chromophores Based on Pyrrole-Hydrazono Donor Moieties (pages 6175–6185)

      Alessandro Abbotto, Luca Beverina, Norberto Manfredi, Giorgio A. Pagani, Graziano Archetti, Hans-Georg Kuball, Christian Wittenburg, Jürgen Heck and Jan Holtmann

      Version of Record online: 6 MAY 2009 | DOI: 10.1002/chem.200900287

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      Donor1+donor2[RIGHTWARDS ARROW]acceptor: The second-order NLO molecular properties of a class of dipolar chromophores that incorporate the following design elements are investigated: 1) a substituted hydrazono moiety as a strong donor; 2) a pyrrole ring as an auxiliary donor; 3) strong acceptor groups (see figure). Their first hyperpolarisabilities show good promise for use in electro-optical devices.

    9. Homoleptic Cyanates

      Urea Route to Homoleptic Cyanates—Characterization and Luminescence Properties of [M(OCN)2(urea)] and M(OCN)2 with M=Sr, Eu (pages 6186–6193)

      Sandro Pagano, Giuseppe Montana, Claudia Wickleder and Wolfgang Schnick

      Version of Record online: 14 MAY 2009 | DOI: 10.1002/chem.200900053

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      Shine a light with cyanates: A novel approach for the synthesis of urea complexes and homoleptic cyanates of alkaline earth metals and europium is described. The compounds have been fully characterized, including their magnetism and temperature-dependent luminescence properties (see graphic).

    10. Fluorescent Probes

      Use of an Osmium Complex as a Universal Luminescent Probe for Enzymatic Reactions (pages 6194–6198)

      Ana Virel, Jose Sanchez-Lopez, Laura Saa, Ana Carla García and Valeri Pavlov

      Version of Record online: 14 MAY 2009 | DOI: 10.1002/chem.200900498

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      Enzymatic modulation of fluorescence: The oxidised form of the OsIII complex is fluorescent in aqueous solution, whereas the reduced OsII form shows no significant fluorescence. This universal approach can be easily adapted to follow any enzymatic reaction to yield oxidising or reducing products capable of interacting with the reduced or oxidised form of the osmium complex, respectively (see figure).

    11. Domino Reactions

      Asymmetric Allylation of Methyl Ketones by Using Chiral Phenyl Carbinols (pages 6199–6210)

      Lutz F. Tietze, Tom Kinzel and Thomas Wolfram

      Version of Record online: 14 MAY 2009 | DOI: 10.1002/chem.200900062

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      To methyl or to alkyl? High induced facial selectivities and excellent yields are obtained in the allylation of aliphatic methyl ketones by using a structurally simple phenylbenzyl auxiliary to give the corresponding homoallylic ethers (see scheme). The transferred auxiliary has a very good protecting quality and can easily be removed.

    12. Monodentate DNA Binding

      Energetics, Conformation, and Recognition of DNA Duplexes Modified by Methylated Analogues of [PtCl(dien)]+ (pages 6211–6221)

      Olga Nováková, Jaroslav Malina, Jana Kašpárková, Anna Halámiková, Vladan Bernard, Francesco Intini, Giovanni Natile and Viktor Brabec

      Version of Record online: 15 MAY 2009 | DOI: 10.1002/chem.200900388

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      Monodentate DNA binding of [PtCl(dien)]+ (dien=diethylenetriamine) complexes may considerably affect the biophysical properties of DNA and consequently downstream cellular processes as a result of a large increase in the bulkiness of the nonleaving ligand by multiple methylation (see illustration).

    13. Metallophilic Interactions

      Multiple Evidence for Gold(I)⋅⋅⋅Silver(I) Interactions in Solution (pages 6222–6233)

      Eduardo J. Fernández, Christopher Hardacre, Antonio Laguna, M. Cristina Lagunas, José M. López-de-Luzuriaga, Miguel Monge, Manuel Montiel, M. Elena Olmos, Raquel C. Puelles and Eva Sánchez-Forcada

      Version of Record online: 13 MAY 2009 | DOI: 10.1002/chem.200900167

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      Metallophilic Au⋅⋅⋅Ag interactions exist in concentrated solutions as well as in the 2D polymeric solid-state structure of [AuAg3(C6F5)(CF3CO2)3(CH2PPh3)]n (see picture for the asymmetric unit) according to EXAFS and pulsed-gradient spin-echo NMR spectroscopy measurements. Calculations support both the emission assignments and the existence of the metallophilic interactions in solution.

    14. Organogels

      Tunable Gel Formation by Both Sonication and Thermal Processing in a Cholesterol-Based Self-Assembly System (pages 6234–6243)

      Junchen Wu, Tao Yi, Qian Xia, Ying Zou, Feng Liu, Jie Dong, Tianmin Shu, Fuyou Li and Chunhui Huang

      Version of Record online: 13 MAY 2009 | DOI: 10.1002/chem.200900409

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      Sonication-induced gelation: Adaptive gels that are responsive to ultrasound were prepared and characterized. The self-assembly of the gelators can be controlled by ultrasound (S-gel) stimuli and renewed by a thermodynamic process (T-gel, see images).

    15. Antibiotics

      Total Syntheses of a Conformationally Locked North-Type Methanocarba Puromycin Analogue and a Dinucleotide Derivative (pages 6244–6257)

      Benoît Y. Michel and Peter Strazewski

      Version of Record online: 13 MAY 2009 | DOI: 10.1002/chem.200802629

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      Locked in translation: Crucial insight into the ribosomal catalysis of peptide-bond formation is expected to be gained from the target compounds, which feature conformational locking in a North-type pucker, designed to interfere with the translation of the genetic code. The compounds were prepared from D-ribose in 18 and 19 steps by a multi-step synthetic route described here (see scheme).

    16. Osmabenzenes

      Osmabenzenes from Osmacycles Containing an η2-Coordinated Olefin (pages 6258–6266)

      Lei Gong, Zhening Chen, Yumei Lin, Xumin He, Ting Bin Wen, Xin Xu and Haiping Xia

      Version of Record online: 6 MAY 2009 | DOI: 10.1002/chem.200900214

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      Osmabenzenes can be easily synthesized from two η2-coordinated olefin osmacycles in the presence of benzonitrile by means of facile hydrogen-transfer conversions (see graphic). Mechanisms for the formation of osmabenzenes are proposed based on DFT calculations.

    17. Catalyst Library

      Design of a Genetic Algorithm for the Simulated Evolution of a Library of Asymmetric Transfer Hydrogenation Catalysts (pages 6267–6278)

      Nicolas Vriamont, Bernadette Govaerts, Pierre Grenouillet, Claude de Bellefon and Olivier Riant

      Version of Record online: 12 MAY 2009 | DOI: 10.1002/chem.200802192

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      Breeding new catalysts: A library of 1980 catalysts was designed for asymmetric hydrogen transfer to acetophenone. The library was submitted to evaluation and further simulated evolution experiments, based on a genetic algorithm (see scheme). We demonstrated that it was easily possible to get 5–6 of the ten best catalysts, while investigating only 10% of the library.

    18. Complementary Assembly

      Silylated Melamine and Cyanuric Acid as Precursors for Imprinted and Hybrid Silica Materials with Molecular Recognition Properties (pages 6279–6288)

      Guilhem Arrachart, Carole Carcel, Philippe Trens, Jöel J. E. Moreau and Michel Wong Chi Man

      Version of Record online: 13 MAY 2009 | DOI: 10.1002/chem.200900278

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      Imprinted materials: Monosilylated derivatives of melamine and cyanuric acid are used in the preparation of hybrid silica. The assembly of the melamine and cyanuric acid moieties through molecular recognition properties is the key factor in building a bridged silsesquioxane and an imprinted hybrid silica (see picture).

  6. Preview

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. News
    5. Communications
    6. Full Papers
    7. Preview
    1. Preview: Chem. Eur. J. 26/2009 (page 6295)

      Version of Record online: 5 JUN 2009 | DOI: 10.1002/chem.200990094

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