Chemistry - A European Journal

Cover image for Vol. 18 Issue 7

February 13, 2012

Volume 18, Issue 7

Pages 1845–2163

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Review
    7. Communications
    8. Full Papers
    9. Preview
    1. You have free access to this content
      Cover Picture: Pathway of Oxygen Incorporation from O2 in TiO2 Photocatalytic Hydroxylation of Aromatics: Oxygen Isotope Labeling Studies (Chem. Eur. J. 7/2012) (page 1845)

      Dr. Yue Li, Dr. Bo Wen, Cailan Yu, Dr. Chuncheng Chen, Dr. Hongwei Ji, Dr. Wanhong Ma and Dr. Jincai Zhao

      Article first published online: 3 FEB 2012 | DOI: 10.1002/chem.201290021

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      The photocatalytic hydroxylation of aromatic compounds has been investigated by an 18O-labeling method. The results show that the reduction of O2 by conduction-band electrons is indispensable for the O2 incorporation. The formed intermediate H2O2 plays an essential role in the O2 incorporation process. The .OH generated from the reduction of H2O2 is the final active species that introduces the O2-derived O atoms into the hydroxylated product. For more details see the Full Paper by C. Chen et al. on page 2030 ff.

  2. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Review
    7. Communications
    8. Full Papers
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    1. Graphical Abstract: Chem. Eur. J. 7/2012 (pages 1848–1857)

      Article first published online: 3 FEB 2012 | DOI: 10.1002/chem.201290022

  3. Corrigendum

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Review
    7. Communications
    8. Full Papers
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    1. You have free access to this content
      Corrigendum: Mechanism Selection for Regiocontrol in Base-Assisted, Palladium-Catalysed Direct C[BOND]H Coupling with Halides: First Approach for Oxazole- and Thiazole-4-Carboxylates (page 1857)

      Laure Théveau, Dr. Cécile Verrier, Pierrik Lassalas, Dr. Thibaut Martin, Prof. Dr. Georges Dupas, Dr. Olivier Querolle, Dr. Luc Van Hijfte, Prof. Dr. Francis Marsais and Dr. Christophe Hoarau

      Article first published online: 3 FEB 2012 | DOI: 10.1002/chem.201200102

  4. News

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

    1. Top of page
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    4. Corrigendum
    5. News
    6. Review
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    1. Bimetallic Catalysis

      Bimetallic Catalysis using Transition and Group 11 Metals: An Emerging Tool for C[BOND]C Coupling and Other Reactions (pages 1864–1884)

      Dr. Mónica H. Pérez-Temprano, Dr. Juan A. Casares and Prof. Dr. Pablo Espinet

      Article first published online: 20 JAN 2012 | DOI: 10.1002/chem.201102888

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      Two are better than one: Bimetallic catalysis, combining the action of at least two non-main-group metals for the formation of C[BOND]C bonds and other reactions, has been quietly growing in very recent years. Pd and Cu or Au initially dominated the topic, but other metals are joining the feast (see figure). This review brings together knowledge coming from classic inorganic and organometallic studies on polymetallic systems and the newer studies in the field of bimetallic catalysis.

  6. Communications

    1. Top of page
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    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Review
    7. Communications
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    1. Energetic Materials

      Synthesis and Characterization of Energetic 3-Nitro-1,2,4-oxadiazoles (pages 1886–1889)

      Zhanda Fu, Rui Su, Yang Wang, Yao-Feng Wang, Wei Zeng, Nan Xiao, Dr. Yukai Wu, Prof. Dr. Zhiming Zhou, Prof. Dr. Jun Chen and Prof. Dr. Fu-Xue Chen

      Article first published online: 20 JAN 2012 | DOI: 10.1002/chem.201103159

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      All new: 3-Nitro-5-guanidino-1,2,4-oxadiazole (NOG) was synthesized from diaminoglycoluril with in situ generated dimethyldioxirane (DMDO). The impact sensitivity of NOG is more than 40 J with a decomposition temperature of 290 °C. Some other energetic derivatives have been prepared and characterized.

    2. Donor–Acceptor Systems

      Unsymmetrical p-Carborane Backbone as a Linker for Donor–Acceptor Dyads (pages 1890–1895)

      Delphine Hablot, Alexandra Sutter, Dr. Pascal Retailleau and Dr. Raymond Ziessel

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201103307

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      Fluorescent nanorods: Donor–acceptor dyads based on novel unsymmetrically disubstituted closo-1,12-dicarbadecaboranes have been prepared in a completely controlled manner by using a three-step procedure. Dyads with different donor–acceptor spacing were thereby obtained. Efficient energy transfer from the donor to the acceptor was determined in fluid solution at room temperature.

    3. Host–Guest Systems

      Weakly Associated TFPB Anions Are Superior to PF6 Anions When Preparing (Pseudo)Rotaxanes from Crown Ethers and Secondary Dialkylammonium Ions (pages 1896–1900)

      Nai-Chia Chen, Chun-Ju Chuang, Liang-Yun Wang, Prof. Chien-Chen Lai and Prof. Sheng-Hsien Chiu

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201103464

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      Making the right choice: Tetrakis(3,5-trifluoromethylphenyl)borate (TFPB) counter anions can facilitate the threading of dibenzylammonium (DBA+) ions through macrocycles in cases where the corresponding PF6 salts fail to exhibit complexation.

    4. Metal–Organic Frameworks

      High Separation Capacity and Selectivity of C2 Hydrocarbons over Methane within a Microporous Metal–Organic Framework at Room Temperature (pages 1901–1904)

      Dr. Yabing He, Dr. Zhangjing Zhang, Dr. Shengchang Xiang, Dr. Hui Wu, Dr. Frank R. Fronczek, Dr. Wei Zhou, Prof. Dr. Rajamani Krishna, Prof. Dr. Michael O'Keeffe and Prof. Dr. Banglin Chen

      Article first published online: 20 JAN 2012 | DOI: 10.1002/chem.201103927

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      A separation story! A microporous metal–organic framework (UTSA-34) of non-interpenetrated binodal (4,6)-connected ybh network with interconnected cages of about 12.8 Å has been realised to exhibit highly selective separation of C2 hydrocarbons from methane with a separation capacity of 3.0 mol kg−1 and selectivity of 35 at room temperature (see figure).

    5. Cascade Cyclization

      FeCl3⋅6H2O-Catalyzed Intermolecular-Cascade Cyclization of Acetoacetanilide: Aldehyde-Tuned Synthesis to Valuable 2-Pyridone Analogues (pages 1905–1909)

      Tista Sengupta, Krishnanka S. Gayen, Dr. Palash Pandit and Dr. Dilip K. Maiti

      Article first published online: 20 JAN 2012 | DOI: 10.1002/chem.201103354

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      The first ever breakthrough toward activation of β-ketoacetanilide and subsequent C[BOND]C and C[BOND]N bond-forming intermolecular-cascade cyclization processes is demonstrated by development of the unprecedented Lewis acid property of non-toxic FeCl36H2O. Aromatic, aliphatic, α,β-unsaturated, chiral sugar-based and chromone aldehydes were regio- and stereoselectively cyclized with acetoacetanilides toward construction of valuable N-containing highly functionalized 2-pyridones (see scheme for an example).

    6. Depolymerization

      Zinc-Catalyzed Depolymerization of Artificial Polyethers (pages 1910–1913)

      Dr. Stephan Enthaler and Maik Weidauer

      Article first published online: 17 JAN 2012 | DOI: 10.1002/chem.201103677

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      Recycling polymers: In the present study, the efficient zinc-catalyzed depolymerization of a variety of artificial polyethers has been investigated. Chloroesters were obtained as the depolymerization products, which are suitable precursors for new polymers. By using straightforward zinc salts, extraordinary catalyst activities and selectivities were feasible (see scheme).

    7. Heterocycle Synthesis

      N-Heterocyclic Carbene Catalyzed Reactions of α-Bromo-α,β-unsaturated Aldehydes/α,β-Dibromoaldehydes with 1,3-Dinucleophilic Reagents (pages 1914–1917)

      Prof. Dr. Changsheng Yao, Donglin Wang, Jun Lu, Prof. Dr. Tuanjie Li, Weihui Jiao and Prof. Chenxia Yu

      Article first published online: 19 JAN 2012 | DOI: 10.1002/chem.201103358

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      Carbenes ring true: N-Heterocyclic carbene (NHC) catalyzed reactions of α-bromo-α,β-unsaturated aldehydes/α,β-dibromoaldehydes with 1,3-dinucleophilic reagents, such as 1,3-dicarbonyl compounds, β-enamino ketones, and β-enamino esters through umpolung processes gave functionalized 3,4-dihydropyranones and 3,4-dihydropyridinones (see scheme). The availability of the starting materials, lack of external oxidant, and usefulness of the products make this strategy attractive.

    8. Organocatalysis

      Active Conformation in Amine–Thiourea Bifunctional Organocatalysis Preformed by Catalyst Aggregation (pages 1918–1922)

      Dr. Gábor Tárkányi, Dr. Péter Király, Dr. Tibor Soós and Szilárd Varga

      Article first published online: 20 JAN 2012 | DOI: 10.1002/chem.201102701

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      Self-activation: Takemoto's catalyst gains access to its active conformation by equilibrating between its hydrogen-bonded intra- and intermolecular interactions in apolar aprotic solvents. By destabilization of the inactive monomeric conformations, the extended antianti thiourea conformation is preformed in the assembly. On leaving the assembly, this transient conformation has a structural preference to become a catalytically active monomeric species that has the potency for dual activation (see scheme).

  7. Full Papers

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Review
    7. Communications
    8. Full Papers
    9. Preview
    1. Metal–Organic Frameworks

      Borromean-Entanglement-Driven Assembly of Porous Molecular Architectures with Anion-Modified Pore Space (pages 1924–1931)

      Jian-Ke Sun, Dr. Qing-Xia Yao, Yu-Yang Tian, Lei Wu, Prof. Guang-Shan Zhu, Dr. Rui-Ping Chen and Prof. Jie Zhang

      Article first published online: 20 JAN 2012 | DOI: 10.1002/chem.201102938

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      You're a Borromeanie: Borromean-entangled porous frameworks (an example is shown here) that can accommodate different kinds of anions with various sizes, shapes, and locations demonstrate the superstability of Borromean linkages and their potential in constructing porous frameworks with tunable pore environments.

    2. C[BOND]H Activation

      On the Mechanism of the Palladium-Catalyzed β-Arylation of Ester Enolates (pages 1932–1944)

      Dr. Paolo Larini, Dr. Christos E. Kefalidis, Dr. Rodolphe Jazzar, Dr. Alice Renaudat, Dr. Eric Clot and Prof. Dr. Olivier Baudoin

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201103153

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      The palladium-catalyzed β-arylation of ester enolates is proposed to occur through a rate-determining palladium–enolate-to-homoenolate isomerization, whereas α-arylation occurs through the reductive elimination of the palladium–enolate intermediate.

    3. Biomineralization

      Protein-Assisted Synthesis of Double-Shelled CaCO3 Microcapsules and Their Mineralization with Heavy Metal Ions (pages 1945–1952)

      Xuan Qi Li, Prof. Zhiwei Feng, Yinyan Xia and Prof. Hua Chun Zeng

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201102877

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      Body building: A protein-assisted approach to synthesize CaCO3 into a double-shelled structural configuration is reported. Three mineralization modes resembling those found in biologically controlled mineralization were found with these bacterium-like CaCO3 microcapsules (see figure).

    4. Fluorescent Probes

      Detection of Nickel in Fish Organs with a Two-Photon Fluorescent Probe (pages 1953–1960)

      Min Young Kang, Chang Su Lim, Hyun Soo Kim, Eun Won Seo, Prof. Dr. Hwan Myung Kim, Dr. Ohyun Kwon and Prof. Dr. Bong Rae Cho

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201103191

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      Sleeping with the fishes: A two-photon fluorescent probe (ANi2) can be excited by 750 nm femtosecond pulses and can detect Ni2+ ions in fresh fish organs at 90–175 μm depth without interference from the pH value and other biologically relevant species.

    5. Photochemistry

      Long-Lived Room-Temperature Near-IR Phosphorescence of BODIPY in a Visible-Light-Harvesting N^C^N PtII–Acetylide Complex with a Directly Metalated BODIPY Chromophore (pages 1961–1968)

      Wanhua Wu, Prof. Jianzhang Zhao, Dr. Huimin Guo, Jifu Sun, Shaomin Ji and Zilong Wang

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201102634

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      Room-temperature phosphorescence of boron dipyrromethene (BODIPY) was observed in a PtII–acetylide complex, in which two PtII atoms were connected to the π core of BODIPY. The complex was used for triplet–triplet annihilation-based upconversion.

    6. Stereoselective Amine Synthesis

      A Versatile Ru Catalyst for the Asymmetric Transfer Hydrogenation of Both Aromatic and Aliphatic Sulfinylimines (pages 1969–1983)

      Óscar Pablo, Dr. David Guijarro, Dr. Gábor Kovács, Dr. Agustí Lledós, Dr. Gregori Ujaque and Dr. Miguel Yus

      Article first published online: 11 JAN 2012 | DOI: 10.1002/chem.201102426

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      Ways and (a)mines: A highly efficient Ru catalyst based on an achiral amino alcohol ligand has been developed for the asymmetric transfer hydrogenation of chiral N-(tert-butylsulfinyl)imines. The diastereoselective reduction of aromatic and aliphatic sulfinylketimines, followed by desulfinylation, affords highly enantiomerically enriched amines in excellent yields. The origin of the diastereoselectivity has been rationalized by DFT calculations.

    7. Structure Elucidation

      Calcium–Amidoborane–Ammine Complexes: Thermal Decomposition of Model Systems (pages 1984–1991)

      Prof. Dr. Sjoerd Harder, Dr. Jan Spielmann and Briac Tobey

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201102029

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      Taking a DIPP: Detailed structural insight into calcium–amidoborane–ammine complexes has been obtained by the syntheses and thermal decompositions of model systems that contain the DIPP-nacnac ligand. The ammonia ligands are involved in extensive hydrogen-bonding networks and N[BOND]H⋅⋅⋅N[BOND]B interactions. These interactions determine the decomposition and hydrogen-desorption pathways.

    8. Light Harvesting

      Enhanced Fluorescence Detection of Metal Ions Using Light-Harvesting Mesoporous Organosilica (pages 1992–1998)

      Dr. Minoru Waki, Dr. Norihiro Mizoshita, Yoshifumi Maegawa, Takeru Hasegawa, Dr. Takao Tani, Dr. Toyoshi Shimada and Dr. Shinji Inagaki

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201102492

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      Fluorescence chemosensors: Periodic mesoporous organosilica with a fluorescent 2,2′-bipyridine receptor attached in the mesochannels showed enhanced fluorescence quenching or band shift upon the addition of a low concentration of metal ions (Cu2+, Zn2+, etc.) because of the unique light-harvesting property of the mesoporous organosilica (see figure).

    9. Macrocyclic Compounds

      Tri- and Pentacalix[4]pyrroles: Synthesis, Characterization and Their Use in the Extraction of Halide Salts (pages 1999–2005)

      Dr. Abdullah Aydogan and Ahmet Akar

      Article first published online: 11 JAN 2012 | DOI: 10.1002/chem.201101605

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      Fishing out the halides: Oligomeric calix[4]pyrrole compounds were synthesized by click chemistry and demonstrated to be capable of extracting tetrabutylammonium chloride and fluoride salts from aqueous media (see figure).

    10. Conformation Analysis

      Designing Fluorinated Cinchona Alkaloids for Enantioselective Catalysis: Controlling Internal Rotation by a Fluorine-Ammonium Ion gauche Effect (φNCCF) (pages 2006–2013)

      Eva-Maria Tanzer, Dr. W. Bernd Schweizer, Dr. Marc-Olivier Ebert and Prof. Dr. Ryan Gilmour

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201102859

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      Fixed with fluorine! The C9 position of cinchona alkaloids functions as a molecular hinge, with internal rotations around the C8[BOND]C9 (τ1) and C9[BOND]C4′ (τ2) bonds giving rise to four low-energy conformers. By substituting the C9 carbinol centre by a configurationally defined fluorine, a fluorine-ammonium gauche effect encodes for two out of the four possible conformers. This constitutes a partial solution to the long-standing problem of governing internal rotations in cinchonium-based catalysts.

    11. Rare-Earth Metals

      Monodisperse REPO4 (RE=Yb, Gd, Y) Hollow Microspheres Covered with Nanothorns as Affinity Probes for Selectively Capturing and Labeling Phosphopeptides (pages 2014–2020)

      Dr. Gong Cheng, Prof. Ji-Lin Zhang, Dr. Yan-Lin Liu, Prof. De-Hui Sun and Prof. Jia-Zuan Ni

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201103328

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      Nanothorn in the flesh: The prickly REPO4 (RE=Yb, Gd, Y) hollow microspheres, which have low densities, high specific surface areas, and large adsorptive capacities, are promising affinity probes because they can selectively trap and label phosphopeptides from complex biological samples based on the specific affinity and catalysis of the rare-earth ions and their unique hierarchical architectures.

    12. Crystal Engineering

      Lattice Effects on the Spin-Crossover Profile of a Mononuclear Manganese(III) Cation (pages 2021–2029)

      Dr. Komala Pandurangan, Brendan Gildea, Dr. Caroline Murray, Dr. Charles J. Harding, Dr. Helge Müller-Bunz and Dr. Grace G. Morgan

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201102820

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      Up, up, up and away! The choice of anion and crystallising solvent has a marked effect on the spin-transition profile of a manganese(III) complex with an N4O2 donor set. Low-spin and gradual spin-crossover profiles are observed between 10–300 K for the ethanol, methanol and acetonitrile solvates of a series of salts of the [MnL]+ ion (see figure).

    13. Photocatalytic Hydroxylation

      Pathway of Oxygen Incorporation from O2 in TiO2 Photocatalytic Hydroxylation of Aromatics: Oxygen Isotope Labeling Studies (pages 2030–2039)

      Dr. Yue Li, Dr. Bo Wen, Cailan Yu, Dr. Chuncheng Chen, Dr. Hongwei Ji, Dr. Wanhong Ma and Dr. Jincai Zhao

      Article first published online: 20 JAN 2012 | DOI: 10.1002/chem.201103446

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      O2can do! An 18O-labeling method is used to study the TiO2 photocatalytic hydroxylation of aromatic compounds. The isotope abundance of the hydroxyl O atom in the product depends markedly on reaction conditions and irradiation time. Experiments show that the main O2-incorporation pathway involves the reduction of O2 by conduction-band electrons and the subsequent formation of .OH, via H2O2.

    14. Lone Pair Influence

      The Importance of Stereochemically Active Lone Pairs For Influencing PbII and AsIII Protein Binding (pages 2040–2050)

      Dr. Giuseppe Zampella, Dr. Kosh P. Neupane, Dr. Luca De Gioia and Prof. Dr. Vincent L. Pecoraro

      Article first published online: 9 JAN 2012 | DOI: 10.1002/chem.201102786

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      Experimental and computational methods have been employed to study the influence of the lone pair of AsIII and PbII for the binding of these ions in proteins using designed peptide models. The results show that the mode of coordination of AsIII and PbII is greatly influenced by the steric bulk within the second coordination environment of the metals (see figure).

    15. Picosecond Crystallography

      100 Picosecond Diffraction Catches Structural Transients of Laser-Pulse Triggered Switching in a Spin-Crossover Crystal (pages 2051–2055)

      Prof. Eric Collet, Dr. Maciej Lorenc, Dr. Marco Cammarata, Dr. Laurent Guérin, Dr. Marina Servol, Dr. Antoine Tissot, Dr. Marie-Laure Boillot, Prof. Hervé Cailleau and Prof. Marylise Buron-Le Cointe

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201103048

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      The photo-switching dynamics of single crystals of the spin-crossover complex [(TPA)Fe(TCC)]PF6, (see figure) have been investigated by time-resolved X-ray diffraction spectroscopy. This study has revealed a rich variety of structural reorganizations involved in the photoinduced spin-state switching. TPA=tris(2-pyridyl methyl)amine, TCC2−=3,4,5,6-Cl4- catechol2−; LS=low spin, HS=high spin.

    16. Charge Transfer

      Excess-Electron Injection and Transfer in Terthiophene-Modified DNA: Terthiophene as a Photosensitizing Electron Donor for Thymine, Cytosine, and Adenine (pages 2056–2062)

      Man Jae Park, Prof. Dr. Mamoru Fujitsuka, Prof. Dr. Kiyohiko Kawai and Prof. Dr. Tetsuro Majima

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201103663

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      A life of excess: Efficient excess-electron injection from singlet-excited terthiophene to several nucleobases, including thymine, cytosine, and adenine, was observed despite adenine being a well-known hole conductor. From studies on DNA hairpins, the possibilities of smaller β value and/or charge delocalization were discussed. In addition, excess-electron transfer through consecutive cytosine nucleobases was suggested.

    17. Carbon Fixation

      Elements of Metabolic Evolution (pages 2063–2080)

      Dr. Claudia Huber, Dr. Florian Kraus, Dr. Marianne Hanzlik, Dr. Wolfgang Eisenreich and Prof. Günter Wächtershäuser

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201102914

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      Combat evolved: The metal-catalyzed reductive conversion of volcanic C1 compounds into organic products is studied under aqueous conditions at high temperatures and high pressures. The detected product mixtures provide evidence for carbon-fixation reactions as potential core pathways for metabolic evolution in a volcanic hydrothermal origin-of-life context.

    18. Nitrogen Heterocycles

      Acid–Base-Catalysed Condensation Reaction in Water: Isoxazolines and Isoxazoles from Nitroacetates and Dipolarophiles (pages 2081–2093)

      Dr. Elena Trogu, Dr. Claudia Vinattieri, Prof. Francesco De Sarlo and Prof. Dr. Fabrizio Machetti

      Article first published online: 10 JAN 2012 | DOI: 10.1002/chem.201102264

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      Wetter is better: The title reactions occur “in water” or “on water” without an induction period, as shown by kinetic profiles in water and in chloroform (see figure). The use of any base, either organic or inorganic, in a 0.1 molar ratio to base to nucleophile gives the best conversion. The results agree with a reversible cycloaddition followed by acid-catalysed irreversible dehydration of the cycloadduct. The reaction is compatible with a wide variety of functional groups.

    19. Layered Compounds

      Synthesis of Uniform Layered Protonated Titanate Hierarchical Spheres and Their Transformation to Anatase TiO2 for Lithium-Ion Batteries (pages 2094–2099)

      Hao Bin Wu, Prof. Xiong Wen (David) Lou and Prof. Huey Hoon Hng

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201102628

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      Storage in the round: Layered protonated titanate hierarchical spheres (LTHSs, see figure) constructed from ultrathin nanosheets have been synthesized by a facile solvothermal method. Their size and morphology can be easily tuned by varying experimental parameters. They can also be converted into porous anatase TiO2 hierarchical spheres, which manifest exceptional Li-storage capabilities.

    20. Gold Complexes

      Constrained Digold(I) Diaryls: Syntheses, Crystal Structures, and Photophysics (pages 2100–2112)

      Dr. David V. Partyka, Thomas S. Teets, Dr. Matthias Zeller, Dr. James B. Updegraff III, Prof. Allen D. Hunter and Prof. Thomas G. Gray

      Article first published online: 11 JAN 2012 | DOI: 10.1002/chem.201101891

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      Gold(I) aryl complexes bridged by Xantphos-type ligands (see figure) show aryl-centered luminescence, regardless of where the LUMO lies. Crystallographic and spectroscopic characterizations are reported, as are DFT calculations.

    21. Reaction Mechanism

      Electrophilic Arene Hydroxylation and Phenol O[BOND]H Oxidations Performed by an Unsymmetric μ-η11-O2-Peroxo Dicopper(II) Complex (pages 2113–2122)

      Isaac Garcia-Bosch, Dr. Xavi Ribas and Dr. Miquel Costas

      Article first published online: 16 JAN 2012 | DOI: 10.1002/chem.201102372

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      The way it goes: Reactions of complex [CuII2(μ-η11-O2)(L)]2+ (1 O2) with phenolates and phenols are described (see scheme). Whereas 1 O2 reacts with PhONa performing tyrosinase-like ortho-hydroxylation of the aromatic ring, its reaction with phenols affords C[BOND]C coupling products. Mechanistic studies reveal that the presence of a H+ completely determines the fate of the association complex [1 O2-(PhO(H))] between a proton-coupled electron transfer (PCET) and an arene hydroxylation reaction.

    22. Bioorganic Chemistry

      Semi-Synthesis of Unusual Chondroitin Sulfate Polysaccharides Containing GlcA(3-O-sulfate) or GlcA(2,3-di-O-sulfate) Units (pages 2123–2130)

      Dr. Emiliano Bedini, Dr. Cristina De Castro, Prof. Mario De Rosa, Annalida Di Nola, Dr. Odile F. Restaino, Prof. Chiara Schiraldi and Prof. Michelangelo Parrilli

      Article first published online: 9 JAN 2012 | DOI: 10.1002/chem.201102458

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      Unusual sulfation patterns: The transformation of chondroitin, produced by E. coli K4 fed–batch fermentation, into chondroitin sulfate (CS) polysaccharides possessing three different sulfation patterns with rare GlcA(3-O-sulfate) or GlcA(2,3-di-O-sulfate) units has been achieved for the first time (see scheme). Key features of the synthetic strategy leading to these CSs are a GalNAc 4,6-diol protection by orthoesterification and an unexpected reluctance of GlcA 3-OH to undergo acylation.

    23. Beryllium Chemistry

      Reactions of Beryllium Halides in Liquid Ammonia: The Tetraammineberyllium Cation [Be(NH3)4]2+, its Hydrolysis Products, and the Action of Be2+ as a Fluoride-Ion Acceptor (pages 2131–2142)

      Dr. Florian Kraus, Dipl.-Chem. Sebastian A. Baer, Dr. Magnus R. Buchner and Dr. Antti J. Karttunen

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201103012

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      Beryllium unraveled! The chemistry of BeF2 and BeCl2 in liquid ammonia has been unraveled. The [Be(NH3)4]2+ cation has been structurally elucidated for the first time (see figure). Its hydrolysis products were found to be the open-chain cation [Be2(μ-OH)(NH3)6]3+ and the cyclic cations [Be2(μ-OH)2(NH3)4]2+ and [Be3(μ-OH)3(NH3)6]3+. [BeF2(NH3)2] is the only dissolved species in liquid ammonia. This compound can be used as a fluoride-ion acceptor and forms [N2H7][BeF3(NH3)].

    24. Microporous Materials

      Towards Mesostructured Zinc Imidazolate Frameworks (pages 2143–2152)

      Sebastian C. Junggeburth, Katharina Schwinghammer, Kulpreet S. Virdi, Prof. Dr. Christina Scheu and Prof. Dr. Bettina V. Lotsch

      Article first published online: 9 JAN 2012 | DOI: 10.1002/chem.201101530

      Thumbnail image of graphical abstract

      The structural analogy between microporous ZIFs and zeolites has been demonstrated to also hold for mesostructured silica materials on the one hand, and mesostructured imidazolate frameworks (MIFs) on the other (see figure). Comprehensive characterization of the obtained MIF materials gives evidence of a lamellar hybrid structure composed of bromine-terminated zinc imidazolate chains, which are sandwiched by cationic surfactant layers.

    25. Ionic Liquids

      Tuning the Physicochemical Properties of Diverse Phenolic Ionic Liquids for Equimolar CO2 Capture by the Substituent on the Anion (pages 2153–2160)

      Prof. Congmin Wang, Dr. Huimin Luo, Prof. Haoran Li, Xiang Zhu, Dr. Bo Yu and Dr. Sheng Dai

      Article first published online: 13 JAN 2012 | DOI: 10.1002/chem.201103092

      Thumbnail image of graphical abstract

      Ionic liquids with good stability, high absorption capacity, and low absorption enthalpy for CO2 capture were achieved by tuning the substituent. The CO2-capture ability of these ionic liquids was significantly affected by the substituent on the anion.

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      Preview: Chem. Eur. J. 8/2012 (page 2163)

      Article first published online: 3 FEB 2012 | DOI: 10.1002/chem.201290024

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