Chemistry - A European Journal

Cover image for Vol. 20 Issue 13

March 24, 2014

Volume 20, Issue 13

Pages 3533–3848

  1. Cover Pictures

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
    1. You have free access to this content
      Cover Picture: The Energy Landscape of Uranyl–Peroxide Species (Chem. Eur. J. 13/2014) (page 3533)

      Dr. Eitan Tiferet, Dr. Adrià Gil, Dr. Carles Bo, Dr. Tatiana Shvareva, Dr. May Nyman and Dr. Alexandra Navrotsky

      Version of Record online: 14 MAR 2014 | DOI: 10.1002/chem.201490050

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      Weighing in… on uranyl phase stability. Two uranyl polyoxometalates that differ only by the anion encapsulated in the center are assessed by computational and experimental methods. Thermodynamic and molecular-orbital calculations agree that stability is gained by increasing cation/anion interactions. This agrees with the trend of all uranyl phases that range in dimension from monomers to infinite solids. For more information, see the Full Paper by M. Nyman, A. Navrotsky et al. on page 3646 ff.

    2. You have free access to this content
      Back Cover: Near-Infrared-Light-Driven Artificial Photosynthesis by Nanobiocatalytic Assemblies (Chem. Eur. J. 13/2014) (page 3852)

      Dr. Joon Seok Lee, Dong Heon Nam, Su Keun Kuk and Prof. Dr. Chan Beum Park

      Version of Record online: 14 MAR 2014 | DOI: 10.1002/chem.201490053

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      Upconversion has been applied to near-infrared (NIR)-light-driven artificial photosynthesis. For the development of an artificial photosynthetic platform that mimics natural photosynthesis in green plants, it is critical to harvest NIR-range light, which constitutes over 46% of the solar energy. In their Communication on page 3584 ff., C. B. Park and co-workers successfully utilize Förster resonance energy transfer between upconversion nanoparticles and organic photosensitizers for efficient photon conversion and photosynthesis under NIR light.

  2. Cover Profile

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
    1. You have free access to this content
      The Energy Landscape of Uranyl–Peroxide Species (page 3536)

      Dr. Eitan Tiferet, Dr. Adrià Gil, Dr. Carles Bo, Dr. Tatiana Shvareva, Dr. May Nyman and Dr. Alexandra Navrotsky

      Version of Record online: 12 MAR 2014 | DOI: 10.1002/chem.201400426

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      Everything is exciting about polyoxometalate chemistry! It is aesthetic, synthetically and computationally challenging, a good size for theoretical studies, and it offers both fundamental and applied science opportunities.” Read more about the story behind the cover in the Cover Profile and about the research itself on page 3646 ff. (DOI: 10.1002/chem.201304076).

  3. Graphical Abstract

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
  4. Corrigendum

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
    1. You have free access to this content
      Corrigendum: Triazole-Tailored Guanosine Dinucleosides as Biomimetic Ion Channels to Modulate Transmembrane Potential (page 3547)

      Y. Pavan Kumar, Rabindra Nath Das, Sonu Kumar, Ole Mathis Schütte, Prof. Dr. Claudia Steinem and Prof. Dr. Jyotirmayee Dash

      Version of Record online: 14 MAR 2014 | DOI: 10.1002/chem.201400427

      This article corrects:
  5. News

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
  6. Minireview

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
    1. Polycyclic Compounds

      Metal-Catalyzed Annulation Reactions for π-Conjugated Polycycles (pages 3554–3576)

      Prof. Dr. Tienan Jin, Dr. Jian Zhao, Prof. Dr. Naoki Asao and Prof. Dr. Yoshinori Yamamoto

      Version of Record online: 3 MAR 2014 | DOI: 10.1002/chem.201304640

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      Elegant synthetic design: Metal-catalyzed annulations for construction of highly π-extended polycycles have been described. A diverse array of annulations, including C[BOND]H bond functionalization, [2+2+2] cycloaddition, cascade annulation, ring-closing metathesis, electrophilic aromatization, and cross-coupling reaction catalyzed by metal complexes, are able to convert the elegantly designed substrates to various π-conjugated poylcycles with high regio-, chemo-, and stereocontrol.

  7. Communications

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
    1. Glycoproteins

      Chemical Synthesis of Asparagine-Linked Archaeal N-Glycan from Methanothermus fervidus (pages 3578–3583)

      Someswara Rao Sanapala and Prof. Dr. Suvarn S. Kulkarni

      Version of Record online: 11 MAR 2014 | DOI: 10.1002/chem.201304950

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      Sweetening up: Herein the first total synthesis of archaeal L-asparagine linked hexasaccharide from Methanothermus fervidus using a highly convergent [3+3] glycosylation approach in high overall yields is reported (see scheme, Troc=trichloroethoxycarbonyl). The synthesis relies on efficient preparation of regioselectively protected thioglycoside building blocks for orthogonal glycosylations and late-stage N-aspartylation.

    2. Upconversion

      Near-Infrared-Light-Driven Artificial Photosynthesis by Nanobiocatalytic Assemblies (pages 3584–3588)

      Dr. Joon Seok Lee, Dong Heon Nam, Su Keun Kuk and Prof. Dr. Chan Beum Park

      Version of Record online: 11 MAR 2014 | DOI: 10.1002/chem.201400136

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      Biocatalytic artificial photosynthesis is enabled with near-infrared (NIR) light, which constitutes over 46 % of the solar energy. Silica-coated upconversion nanoparticles were synthesized for efficient photon-conversion through Förster resonance energy transfer (FRET) with rose bengal, a photosensitizer (see figure). Upconversion nanoparticles with anti-Stokes emission are promising light harvesters of NIR light in solar-to-chemical conversion processes.

    3. Metal–Organic Frameworks

      A Fluorescent Sensor for Highly Selective Detection of Nitroaromatic Explosives Based on a 2D, Extremely Stable, Metal–Organic Framework (pages 3589–3594)

      Dr. Shu-Ran Zhang, Dr. Dong-Ying Du, Dr. Jun-Sheng Qin, Dr. Shao-Juan Bao, Prof. Shun-Li Li, Dr. Wen-Wen He, Prof. Ya-Qian Lan, Dr. Ping Shen and Prof. Zhong-Min Su

      Version of Record online: 27 FEB 2014 | DOI: 10.1002/chem.201304692

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      Detection of explosives: A 2D, extremely stable, metal–organic framework (MOF) was successfully constructed. It displays highly selective and recyclable properties for detection of nitroaromatic explosives as a fluorescent sensor (see figure). This is the first MOF that can distinguish between nitroaromatic molecules with different numbers of [BOND]NO2 groups.

    4. Coordination Chemistry

      Hetero-Epitaxial Approach by Using Labile Coordination Sites to Prepare Catenated Metal–Organic Frameworks with High Surface Areas (pages 3595–3599)

      Dr. Nianyong Zhu, Matthew J. Lennox, Gerard Tobin, Lisa Goodman, Dr. Tina Düren and Prof. Wolfgang Schmitt

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304856

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      Topological blueprint: A solid-state approach that takes advantage of the ordered 3D arrangement of active secondary building units (SBUs) allows the preparation of new interlocked MOFs, which grow hetero-epitaxially on the crystal faces of a precursor phase that acts as a “topological blueprint”. The synthetic strategy is exemplified by using rigid acetylene-based ligands to produce highly augmented CuII acetate based MOFs (see figure).

    5. Silanes

      Synthesis and Structure of Tetraethynylsilane and Its Silylated Derivatives (pages 3600–3605)

      Florian L. Geyer, Dr. Frank Rominger and Prof. Uwe H. F. Bunz

      Version of Record online: 25 FEB 2014 | DOI: 10.1002/chem.201400105

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      Rock stable: Full desilylation of the easily produced tetrakis(trimethylsilylethynyl)silane by using triflic acid gave the parent tetraethynylsilane. It was isolated and purified by sublimation and fully characterized including X-ray crystallography. Attempts to explosively decompose this material failed: it is ultrastable even at elevated temperatures. Partial stepwise deprotection is also possible, and all intermediates were isolated and characterized (see figure).

    6. C[BOND]H Activation

      Ruthenium-Catalyzed C7 Amidation of Indoline C[BOND]H Bonds with Sulfonyl Azides (pages 3606–3609)

      Changduo Pan, Ablimit Abdukader, Jie Han, Prof. Dr. Yixiang Cheng and Prof. Dr. Chengjian Zhu

      Version of Record online: 25 FEB 2014 | DOI: 10.1002/chem.201304236

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      Synthetic methods: A ruthenium-catalyzed direct C7 amidation of indoline C[BOND]H bonds with sulfonyl azides was developed (see scheme, DCE=1,2-dichloroethane). This procedure allows the synthesis of a variety of 7-amino-substituted indolines in good yields. The good functional-group tolerance as well as the mild conditions are prominent features of this method.

    7. Cross-Coupling

      Pd-Catalyzed Decarboxylative Cross-Coupling of 2-Carboxyazine N-Oxides with Various (Hetero)aryl Halides (pages 3610–3615)

      Jean-Baptiste Rouchet, Dr. Cédric Schneider, Dr. Cédric Spitz, Johan Lefèvre, Prof. George Dupas, Dr. Corinne Fruit and Prof. Christophe Hoarau

      Version of Record online: 26 FEB 2014 | DOI: 10.1002/chem.201304773

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      Choose your pathway: Decarboxylative cross-coupling reactions of substituted 2-carboxyazine N-oxides, with a variety of (hetero)aryl halides, by bimetallic Pd0/CuI and Pd0/AgI catalysis are reported (see figure). These methods provide the first general decarboxylative arylation methodology in the 2-carboxyazine series.

    8. Boron

      A Clear-Cut Example of Selective Bpin[BOND]Bdan Activation and Precise Bdan Transfer on Boron Conjugate Addition (pages 3616–3620)

      Jessica Cid, Dr. Jorge J. Carbó and Dr. Elena Fernández

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304615

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      Selective transfer: Activating the non-symmetrical Bpin[BOND]Bdan diboron reagent with alkoxide leads to the formation of two possible adducts: MeO[RIGHTWARDS ARROW]Bpin[BOND]Bdan or MeO[RIGHTWARDS ARROW]Bdan[BOND]Bpin. Experimental and theoretical investigation confirms that the MeO[RIGHTWARDS ARROW]Bpin interaction is preferred and thus selective formation of a C[BOND]Bdan bond upon reaction with an activated C[DOUBLE BOND]C bond.

    9. Organic Synthesis

      NIS-Assisted Aza-Friedel–Crafts Reaction with α-Carbamoysulfides as Precursors of N-Carbamoylimines (pages 3621–3625)

      Dr. Nicolas George, Mathieu Bekkaye, Dr. Aurélien Alix, Prof. Dr. Jieping Zhu and Dr. Géraldine Masson

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201400117

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      Catalytic activation of­ N,S-acetals: A general and practical N-iodosuccinimide (NIS)-promoted aza-Friedel–Crafts reaction of various aromatic nucleophiles with N-acylimines generated in situ from α-amido-sulfides is described. The newly developed methodology is very mild, fast, efficient, and complementary (see scheme).

    10. DNA Nanowires

      Programmed Self-Assembly of a Quadruplex DNA Nanowire (pages 3626–3630)

      Dr. Nason Ma'ani Hessari, Dr. Lea Spindler, Tinkara Troha, Dr. Wan-Chi Lam, Prof. Irena Drevenšek-Olenik and Dr. Mateus Webba da Silva

      Version of Record online: 25 FEB 2014 | DOI: 10.1002/chem.201300692

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      All wired up: A quadruplex DNA wire with uninterrupted π stacking was built based on the encoding of self-assembly on a nine nucleotide sequence (see figure). It is thus feasible to control by design the π-stacking characteristics of these wires to allow for the modulation of mechanical, electronic, and optoelectronic properties at nanoscale dimensions.

    11. Asymmetric Hydrogenation

      Efficient Asymmetric Hydrogenation of α-Acetamidocinnamates through a Simple, Readily Available Monodentate Chiral H-Phosphinate (pages 3631–3635)

      Dr. Xiang-Bo Wang, Dr. Midori Goto and Dr. Li-Biao Han

      Version of Record online: 25 FEB 2014 | DOI: 10.1002/chem.201304675

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      Acting solo: An air-stable, simple monodentate chiral H-phosphinate, readily available in large quantities, can efficiently induce the rhodium-catalyzed asymmetric hydrogenation of α-acetamidocinnamates with high enantioselectivity (up to 99.6 % ee; see scheme, Men=mentyl). Intramolecular hydrogen bonding plays an important role in this asymmetric induction.

  8. Full Papers

    1. Top of page
    2. Cover Pictures
    3. Cover Profile
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Full Papers
    1. Sensors

      Thermal-Induced Formation of a Three-Dimensional Nanoplasmonic Sensor from Ag Nanocubes with High Stability and Reusability (pages 3636–3645)

      Dr. Weiwei Lu, Yingli Song, Dr. Kaisheng Yao and Prof. Dr. Jianji Wang

      Version of Record online: 11 MAR 2014 | DOI: 10.1002/chem.201304383

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      Ag nanocubes assemble: To overcome the drawbacks of low optical signal and high non-specific binding for nanoplasmonic sensors, a new thermal-induced method was proposed to bind Ag nanocubes on both surfaces of the glass by using the unique temperature dependence of hydrophilicity of 2-diethylaminoethanethiol. Furthermore, through overcoating of SiO2 and introduction of NiII-nitriloacetic complex, highly stable and reusable sensors were created (see figure, DEAET=2-(diethylamino)ethanethiol).

    2. Polyoxometalates

      The Energy Landscape of Uranyl–Peroxide Species (pages 3646–3651)

      Dr. Eitan Tiferet, Dr. Adrià Gil, Dr. Carles Bo, Dr. Tatiana Y. Shvareva, Dr. May Nyman and Dr. Alexandra Navrotsky

      Version of Record online: 6 MAR 2014 | DOI: 10.1002/chem.201304076

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      Nanocapsules: Uranyl–peroxide polyoxometalates were templated by encapsulated cations and anions; the stability gained by this encapsulation was quantified. Calorimetry and calculations agree that increasing cation/anion interactions lead to thermodynamic and electronic orbital stabilization. In the broader landscape, the related uranyl–peroxide monomers and extended solids do not have such extensive cation/anion interactions, and thus lack this enthalpic gain (see figure).

    3. Fluorescence

      Regiospecific Formation and Unusual Optical Properties of 2,5-Bis(arylethynyl)rhodacyclopentadienes: A New Class of Luminescent Organometallics (pages 3652–3666)

      Dr. Andreas Steffen, Dr. Richard M. Ward, Dr. Meng Guan Tay, Dr. Robert M. Edkins, Dr. Fabian Seeler, Magda van Leeuwen, Dr. Lars-Olof Pålsson, Prof. Dr. Andrew Beeby, Dr. Andrei S. Batsanov, Prof. Dr. Judith A. K. Howard and Prof. Dr. Todd B. Marder

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304068

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      A single(t) light bulb! A series of 2,5-bis(arylethynyl)rhodacyclopentadienes has been prepared by a rare regiospecific reductive coupling of 1,4-aryl-1,3-butadiynes at a RhI precursor, giving the 2,5-bis(arylethynyl) isomer only (see figure). Despite the presence of the heavy rhodium atom, the metallacyclopentadienes exhibit highly unusual fluorescence with Φf=1–18 %, instead of phosphorescence, with an exceptionally slow triplet-state formation, occurring within nanoseconds.

    4. Zeolites

      Dispersion and Orientation of Zeolite ZSM-5 Crystallites within a Fluid Catalytic Cracking Catalyst Particle (pages 3667–3677)

      Dr. Christoph Sprung and Prof. Dr. Bert M. Weckhuysen

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201303549

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      Utilization of fluorescence anisotropy: Oriented probe molecules are entrapped inside the channels of zeolite ZSM-5. Thus, their fluorescence is anisotropic. Zeolite crystallites were distinguished from binder and matrix material in which they are dispersed, due to oriented emission (see scheme). The quantity, dispersion, and orientation of ZSM-5 crystallites have been determined inside a single fluid catalytic cracking (FCC) particle.

    5. Dyes/Pigments

      New Synthetic Routes towards Soluble and Dissymmetric Triphenodioxazine Dyes Designed for Dye-Sensitized Solar Cells (pages 3678–3688)

      Dr. Yohann Nicolas, Fouzia Allama, Dr. Marc Lepeltier, Dr. Julien Massin, Dr. Frédéric Castet, Dr. Laurent Ducasse, Dr. Lionel Hirsch, Dr. Zahia Boubegtiten, Dr. Gediminas Jonusauskas, Dr. Céline Olivier and Prof. Thierry Toupance

      Version of Record online: 23 FEB 2014 | DOI: 10.1002/chem.201303775

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      Push–pull dyes: New unsymmetrical push–pull triphenodioxazine dyes have been synthesized under mild conditions with fine control of isomerism showing high photostability (see figure). The dye-sensitized solar cells, elaborated from TiO2, dyes, and the iodine/iodide redox couple reached a photoconversion yield of up to 6.3 %.

    6. Ligands

      New RuII(arene) Complexes with Halogen-Substituted Bis- and Tris(pyrazol-1-yl)borate Ligands (pages 3689–3704)

      Dr. Serena Orbisaglia, Dr. Corrado Di Nicola, Prof. Fabio Marchetti, Prof. Claudio Pettinari, Dr. Riccardo Pettinari, Prof. Luísa M. D. R. S. Martins, Prof. Elisabete C. B. A. Alegria, Prof. M. Fátima C. Guedes da Silva, Bruno G. M. Rocha, Dr. Maxim L. Kuznetsov, Prof. Armando J. L. Pombeiro, Prof. Brian W. Skelton, Dr. Alexandre N. Sobolev and Prof. Allan H. White

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304406

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      Fine tuning: A combination of steric and electronic features of bromine-substituted scorpionate ligands and an arene moiety has provided an unexpected μ3-binuclear ionic complex instead of the mononuclear neutral one; this is accounted for by the low thermodynamic stability of the latter species. The coordination chemistry of RuII(arene) toward Tpx ligands was analyzed using X-ray diffraction (see figure), electrochemical and DFT methods.

    7. Aromaticity

      Synthesis and Structural Data of Tetrabenzo[8]circulene (pages 3705–3711)

      Robert W. Miller, Alexandra K. Duncan, Dr. Severin T. Schneebeli, Dr. Danielle L. Gray and Prof. Adam C. Whalley

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304657

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      Harnessing aromaticity: A new synthesis of tetrabenzo[8]circulene is reported. The calculated and experimental data presented herein indicate a strong correlation with the structure predicted by using Clar's theory of aromaticity, which provides insight into the high stability of this structure when compared to previously synthesized analogues. The saddle-shaped structure was found to be malleable and results in a highly twisted structure in the solid state (see figure).

    8. Metal–Organic Frameworks

      Anhydrous Lanthanide MOFs and Direct Photoluminescent Sensing for Polyoxometalates in Aqueous Solution (pages 3712–3723)

      Prof. Qi-Bing Bo, Dr. Hai-Tao Zhang, Dr. Hong-Yan Wang, Dr. Jin-Ling Miao and Prof. Zhen-Wei Zhang

      Version of Record online: 19 FEB 2014 | DOI: 10.1002/chem.201303677

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      Tip for detection: New anhydrous 3D microporous lanthanide metal–organic frameworks (MOFs) with hexagonal channel arrays were synthesized based on the 5-tert-butylisophthalate ligand (tip; see figure). The potential sensing function of the Eu-based MOF for polyoxometalates (POMs) in an aqueous solution is investigated for the first time.

    9. Bioassays

      Alternating Current Electrohydrodynamics Induced Nanoshearing and Fluid Micromixing for Specific Capture of Cancer Cells (pages 3724–3729)

      Ramanathan Vaidyanathan, Dr. Sakandar Rauf, Dr. Eloïse Dray, Dr. Muhammad J. A. Shiddiky and Prof. Matt Trau

      Version of Record online: 23 FEB 2014 | DOI: 10.1002/chem.201304590

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      Nanoshearing for cell capture: Tuneable nanoshearing offers a unique capability to preferentially select strongly bound cells over weakly (nonspecifically) bound cells which adhere to the surface. The tuneable nature of this force (by externally tuning the ac field) facilitates an increase in the number of sensor–target collisions and also the ability to shear away nonspecifically bound cellular species (see figure).

    10. Sensors

      Molecular Recognition of Nucleotides in Water by Scorpiand-Type Receptors Based on Nucleobase Discrimination (pages 3730–3741)

      Mario Inclán, Dr. M. Teresa Albelda, Dr. Esther Carbonell, Dr. Salvador Blasco, Antonio Bauzá, Prof. Antonio Frontera and Prof. Enrique García-España

      Version of Record online: 26 FEB 2014 | DOI: 10.1002/chem.201303861

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      Discerning hosts: Scorpiand-type ligands are molecules that are able to form water-soluble complexes with nucleotides. The driving forces leading to the formation of host–guest structures were studied by means of NMR spectroscopy and DFT calculations. These novel receptors are able to effectively and selectively distinguish guanosine-5′-triphosphate (GTP) from adenosine-5′-triphosphate (ATP; see figure).

    11. Phenanthridinium Cations

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      Expanding the Palette of Phenanthridinium Cations (pages 3742–3751)

      Andrew G. Cairns, Dr. Hans Martin Senn, Dr. Michael P. Murphy and Dr. Richard C. Hartley

      Version of Record online: 19 FEB 2014 | DOI: 10.1002/chem.201304241

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      Knock-out!­ N-Alkylphenanthridinium cations have a wide range of applications from DNA dyes to reactive oxygen species sensors to allosteric inhibitors, and tuning for a particular property is important. A versatile modular synthesis of phenanthridinium salts from three components, which concludes with a novel cyclisation involving concerted displacement of fluoride by an N-alkylimine (see illustration, TS=transition state), is presented.

    12. Heterocycles

      Synthesis and Structure of a 1-Phospha-2-boraacenaphthene Derivative and Its Chalcogenation Reactions (pages 3752–3758)

      Dr. Akihiro Tsurusaki, Prof. Dr. Takahiro Sasamori and Prof. Dr. Norihiro Tokitoh

      Version of Record online: 23 FEB 2014 | DOI: 10.1002/chem.201304644

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      P[BOND]Ch[BOND]B heterocycles: The first stable 1-phospha-2-boraacenaphthene was synthesized and fully characterized (see scheme, Mes=mesityl). Its chalcogenation reaction with elemental sulfur or selenium afforded unique heterocycles containing P, B, and chalcogen (Ch) atom(s). The newly obtained chalcogenated compounds have also been characterized. The unique dynamic behavior of 2-chalcogena-1-phospha-3-boraphenalene-1-chalcogenides in solution has also been described.

    13. Sandwich Complexes

      Complexes of Monocationic Group 13 Elements with Pentaphospha- and Pentaarsaferrocene (pages 3759–3768)

      Martin Fleischmann, Dr. Stefan Welsch, Dr. Hannes Krauss, Monika Schmidt, Dr. Michael Bodensteiner, Dr. Eugenia V. Peresypkina, Prof. Dr. Marek Sierka, Dr. Christian Gröger and Prof. Dr. Manfred Scheer

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304466

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      Moving down Group 13: The coordination chemistry of “naked” Ga+, In+, and Tl+ cations towards [Cp*Fe(η5-E5)] (E=P, As) was investigated. The cyclo-P5 and cyclo-As5 complexes bridge the Group 13 cations by a new π- and simultaneous σ-coordination to form one-dimensional polymers (see figure). The obtained complexes are based upon very weak dative bonds and show dynamic behavior in solution. The 31P{1H} magic-angle spinning NMR study even suggests a rotational dynamic in the solid state at room temperature.

    14. Transition Metals

      Magnetochemical Complexity of Hexa- and Heptanuclear Wheel Complexes of Late-3d Ions Supported by N,O-Donor Pyridyl–Methanolate Ligands (pages 3769–3781)

      Dr. Kirill Yu. Monakhov, Dr. Xavier López, Dr. Manfred Speldrich, Dr. Jan van Leusen, Prof. Dr. Paul Kögerler, Prof. Dr. Pierre Braunstein and Prof. Dr. Josep M. Poblet

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304177

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      Transition-metal wheels: The scaffold geometries, stability, and magnetic properties of the (pyridine-2-yl)methanolate (L)-supported wheel-type metal complexes [M6L12] (1), [Na⊂(ML2)6]+ (2), and [M′⊂(ML2)6]2+ (3), in which M=Co, Ni, Cu, and Zn, are strongly influenced by the nature of these late-3d ions in the {M6} rims and of the Na+ and M′2+ ions (XQ+) coordinated within the central voids of the wheels (see figure).

    15. Kinetics

      Cu-Based Catalyst Resulting from a Cu,Zn,Al Hydrotalcite-Like Compound: A Microstructural, Thermoanalytical, and In Situ XAS Study (pages 3782–3792)

      Dr. Stefanie Kühl, Dr. Andrey Tarasov, Dr. Stefan Zander, Dr. Igor Kasatkin and Dr. Malte Behrens

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201302599

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      Highly active cat: A full kinetic analysis was applied to the reduction of layered double hydroxide (LDH) pre-catalysts (see figure). The intermediate formation of CuI was confirmed by using in situ near-edge X-ray absorption fine structure (NEXAFS) analysis. The kinetic analysis allowed the prediction of the phase composition at given reduction conditions. A higher intrinsic activity was found for the catalyst that shows a hindered reduction with a kinetically stabilized CuI intermediate.

    16. Photocatalysis

      Trapped in Imidazole: How to Accumulate Multiple Photoelectrons on a Black-Absorbing Ruthenium Complex (pages 3793–3799)

      Linda Zedler, Dr. Stephan Kupfer, Dr. Inês Rabelo de Moraes, Dr. Maria Wächtler, Prof. Dr. Rainer Beckert, Prof. Dr. Michael Schmitt, Prof. Dr. Jürgen Popp, Prof. Dr. Sven Rau and Prof. Dr. Benjamin Dietzek

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304937

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      Two (photo)electron trapping: The structure of short-lived intermediates concentrating multiple photoelectrons strongly impacts on the efficiency of photocatalysis of, for example, hydrogen generation, but their spectroscopic investigation is challenging. Instead electrochemically generated anions of RuII–4H-imidazole, which are identical to these intermediates, were studied by in situ spectroelectrochemistry and time-dependent density functional theory (TDDFT) calculations, illuminating the intimate interplay of structure and charge-transfer dynamics at the 4H-imidazole unit (see figure).

    17. Screening Methods

      Rapid Assessment of Protecting-Group Stability by Using a Robustness Screen (pages 3800–3805)

      Dr. Karl D. Collins, Andreas Rühling, Fabian Lied and Prof. Dr. Frank Glorius

      Version of Record online: 19 FEB 2014 | DOI: 10.1002/chem.201304508

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      Stable or not? An experimentally simple method has been developed to rapidly establish the stability of widely utilized silyl, acetal, and carbamate protecting groups to a given set of reaction conditions (see figure; Ac=acetyl, Boc=tert-butoxycarbonyl, TBS=tert-butyldimetylsilyl). Assessment of up to twelve protecting groups in a single experiment has been demonstrated. This method could be used to select appropriate protecting groups in the design of synthetic routes.

    18. Enantioselectivity

      Minor Enantiomer Recycling: Application to Enantioselective Syntheses of Beta Blockers (pages 3806–3812)

      Dr. Ye-Qian Wen, Robin Hertzberg, Inanllely Gonzalez and Prof. Christina Moberg

      Version of Record online: 26 FEB 2014 | DOI: 10.1002/chem.201303890

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      Recycling drive: Continuous recycling of the minor product enantiomer from acylcyanation of prochiral aldehydes gave access to highly enantioenriched products (see scheme), which were transformed into β-adrenergic antagonists by means of standard procedures.

    19. Enantioselective Synthesis and Physicochemical Properties of Libraries of 3-Amino- and 3-Amidofluoropiperidines (pages 3813–3824)

      Dr. Aurélie Orliac, Dr. Julie Routier, Dr. Fabienne Burgat Charvillon, Dr. Wolfgang H. B. Sauer, Dr. Agnes Bombrun, Dr. Santosh S. Kulkarni, Dr. Domingo Gomez Pardo and Prof. Janine Cossy

      Version of Record online: 13 FEB 2014 | DOI: 10.1002/chem.201302423

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      Power of F: The enantioselective syntheses of 3-amino-5-fluoropiperidines and 3-amino-5,5-difluoropiperidines (see figure) were realized by using a ring expansion of prolinols. The measurement of the physicochemical properties of the substituted fluoropiperidines revealed the power of fluorine to decrease the pKa and modulate the lipophilicity of 3-aminopiperidines. Conformational modifications of the 3-aminopiperidines induced by fluorine atom(s) were also observed.

    20. C[BOND]H Activation

      Probing the Limits of Ligand Steric Bulk: Backbone C[BOND]H Activation in a Saturated N-Heterocyclic Carbene (pages 3825–3830)

      Nicholas Phillips, Remi Tirfoin and Prof. Simon Aldridge

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201304243

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      How big is too big? The consequences of extremely high steric loading have been probed in late transition metal complexes featuring the expanded ring N-heterocyclic carbene 6-Dipp (Dipp=diisopropyl phenyl). In the presence of [(6-Dipp)Au]+, the first example of backbone C[BOND]H activation of a saturated N-heterocyclic carbene is revealed, proceeding via a mechanism which involves free carbene in addition to the AuI centre (see illustration, Mes=mesityl).

    21. Nucleobases

      On the Use of Metal Purine Derivatives (M=Ir, Rh) for the Selective Labeling of Nucleosides and Nucleotides (pages 3831–3838)

      Marta Valencia, Mamen Martín-Ortiz, Prof. Dr. Mar Gómez-Gallego, Prof. Dr. Carmen Ramírez de Arellano and Prof. Dr. Miguel A. Sierra

      Version of Record online: 23 FEB 2014 | DOI: 10.1002/chem.201304091

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      Labeling nucleobases: Neutral or cationic IrIII and RhIII derivatives of phenyl purine nucleobases insert unsymmetrical alkynes regioselectively to produce new metallacycles (see figure), allowing the incorporation of either photoactive (anthracene or pyrene) or electroactive (ferrocene) labels in the nucleotide or nucleoside moiety. This methodology could be used for the unambiguous labeling of oligonucleotides.

    22. Reaction Mechanisms

      Mechanistic Study on Rh-Catalyzed Stereoselective C[BOND]C/C[BOND]H Activation of tert-Cyclobutanols (pages 3839–3848)

      Dr. Haizhu Yu, Dr. Chen Wang, Yimeng Yang and Prof. Zhi-Min Dang

      Version of Record online: 24 FEB 2014 | DOI: 10.1002/chem.201303249

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      Three out of five steps in the Rh-catalyzed stereoselective transformation of aryl-substituted tert-cyclobutanols into indanols were shown by DFT calculations to make important contributions to determining the stereoselectivity, while the rate-determining step is the 1,4-Rh transfer. The present study corroborated the previous proposal that the reaction occurs by metalation, β-C elimination, 1,4-Rh transfer, C[DOUBLE BOND]O insertion, and a final catalyst-regeneration step (see figure).

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