Chemistry - A European Journal

Cover image for Vol. 18 Issue 41

October 8, 2012

Volume 18, Issue 41

Pages 12905–13225

  1. Cover Pictures

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. News
    5. Concept
    6. Communications
    7. Full Papers
    1. You have free access to this content
      Cover Picture: A Soft Copper(II) Porous Coordination Polymer with Unprecedented Aqua Bridge and Selective Adsorption Properties (Chem. Eur. J. 41/2012) (page 12905)

      Elsa Quartapelle Procopio, Tomohiro Fukushima, Prof. Dr. Elisa Barea, Prof. Dr. Jorge A. R. Navarro, Prof. Dr. Satoshi Horike and Prof. Dr. Susumu Kitagawa

      Version of Record online: 27 SEP 2012 | DOI: 10.1002/chem.201290177

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      The effect of the removal of bridging water molecules of a copper(II) dinuclear secondary building unit of a coordination network, which gives rise to a metastable porous phase with open-metal sites able to respond to thermal and chemical stimuli, is reported by E. Barea, J. A. R. Navarro, S. Kitagawa, and co-workers on page 13117 ff. The gas-adsorption properties of this material have been studied by means of single-component gas-adsorption isotherms and variable-temperature pulse-gas chromatography indicative of switchable adsorptive properties.

    2. You have free access to this content
      Inside Cover: Red-Emitting Rhodamines with Hydroxylated, Sulfonated, and Phosphorylated Dye Residues and Their Use in Fluorescence Nanoscopy (Chem. Eur. J. 41/2012) (page 12906)

      Dr. Kirill Kolmakov, Dr. Christian A. Wurm, Dipl.-Ing. René Hennig, Dr. Erdmann Rapp, Prof. Stefan Jakobs, Dr. Vladimir N. Belov and Prof. Stefan W. Hell

      Version of Record online: 27 SEP 2012 | DOI: 10.1002/chem.201290178

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      “A Study in Scarlet” by Sir Arthur Conan Doyle was a detective novel introducing Sherlock Holmes (who was fond of chemistry) and the magnifying glass as an investigative contraption. Color, chemistry, and contraption all relate to the picture, which shows one of the best red-emitting rhodamine dyes described by C. A. Wurm, V. N. Belov, S. W. Hell et al. in their Full Paper on page 12986 ff. The tubular network in a cell was stained with the dye and imaged in a modern light microscope, a refinement of the magnifying glass, as well as by STED microscopy.

    3. You have free access to this content
      Back Cover: Conformational Analysis of Fluorinated Pyrrolidines Using 19F–1H Scalar Couplings and Heteronuclear NOEs (Chem. Eur. J. 41/2012) (page 13228)

      Lorraine E. Combettes, Philip Clausen-Thue, Dr. Michael A. King, Dr. Barbara Odell, Dr. Amber L. Thompson, Prof. Véronique Gouverneur and Dr. Tim D. W. Claridge

      Version of Record online: 27 SEP 2012 | DOI: 10.1002/chem.201290181

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      Conformational analysis of saturated five-membered rings in solution is particularly complicated due to their inherent flexibility. To tackle this problem, V. Gouverneur, T. D. W. Claridge et al., have optimized 1D 19F–1H heteronuclear NOE (HOESY) experiments for application to small molecules. The method was used to investigate the conformations of fluorinated pyrrolidines in solution and the stabilizing influence of the fluorine gauche effect. Where possible the derived solution-phase structural data have been compared with those of the crystalline state. For more details see the Full Paper on page 13133 ff.

  2. Graphical Abstract

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

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

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. News
    5. Concept
    6. Communications
    7. Full Papers
    1. DNA-Targeted Agents

      DNA Metalating–Intercalating Hybrid Agents for the Treatment of Chemoresistant Cancers (pages 12926–12934)

      Dr. Jimmy Suryadi and Prof. Dr. Ulrich Bierbach

      Version of Record online: 17 SEP 2012 | DOI: 10.1002/chem.201202050

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      Do not bend…intercalate: Metal-containing antitumor agents that react with DNA radically differently to clinical platinum drugs produce a unique spectrum of biological activity. New designs show major pharmacological advantages compared to clinical platinum drugs. This Concept article summarizes milestones and discusses major hurdles and challenges in the preclinical development of platinum–acridine hybrid agents as true magic bullets (see figure).

  5. Communications

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. News
    5. Concept
    6. Communications
    7. Full Papers
    1. Cross-Coupling

      Li+-Mediated B[BOND]C Cross-Coupling (pages 12936–12940)

      David Olid, Prof. Dr. Clara Viñas and Prof. Dr. Francesc Teixidor

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201201881

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      Easy as A, B[BOND]C: B[BOND]C cross-coupling on [3,3′-Co(8-I-1,2-C2B9H10)(1′,2′-C2B9H11)], [1], the best specimen of metallacarboranes, is easily produced in a reaction mediated by Li+ in the absence of a transition-metal catalyst (see figure). Pure RLi or a mixture of Li reagents (tBuLi+RLi) is adequate to produce the B[BOND]C bond. Notably, a threshold of RLi (or tBuLi+RLi)/[1], 2:1, is required to initiate the B[BOND]C coupling, which acts, at least in part, as a source of soluble Li+.

    2. Density Functional Calculations

      Conformational Preferences of Gas-Phase Helices: Experiment and Theory Struggle to Agree: The Seven-Residue Peptide Ac-Phe-(Ala)5-Lys-H+ (pages 12941–12944)

      Dr. Yaoming Xie, Prof. Henry F. Schaefer III, Prof. Radu Silaghi-Dumitrescu, Dr. Bin Peng, Prof. Qian-shu Li, Dr. Jaime A. Stearns and Prof. Thomas R. Rizzo

      Version of Record online: 5 SEP 2012 | DOI: 10.1002/chem.201202068

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      Peptide conformations: IR/UV double-resonance spectroscopy suggested relative energies for four peptide conformations (see figure). These results cannot be reproduced by any of 19 density functional methods.

    3. Tandem Reactions

      A Base-Promoted Tandem Cycloaddition/Air Oxidation Reaction of Electron-Deficient Conjugated Enynes and Hydrazines: Synthesis of Highly Substituted Pyrazoles (pages 12945–12949)

      Dr. Xiuzhao Yu and Prof. Dr. Junliang Zhang

      Version of Record online: 5 SEP 2012 | DOI: 10.1002/chem.201202583

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      Rapid access: A base-mediated cycloaddition/oxidation reaction of hydrazines and electron-deficient 1,3-conjugated enynes gives pyrazole derivatives, some of which are not easily accessible by other methods (see scheme). The reaction conditions are mild, thus enabling a variety of functional groups to be tolerated.

    4. Asymmetric Fluorination

      Organocatalytic Asymmetric Fluorination/Semipinacol Rearrangement: An Efficient Approach to Chiral β-Fluoroketones (pages 12950–12954)

      Zhi-Min Chen, Bin-Miao Yang, Zhi-Hua Chen, Qing-Wei Zhang, Min Wang and Yong-Qiang Tu

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201202444

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      An asymmetric fluorination/semipinacol rearrangement of 2-oxa allylic alcohols, as catalyzed by cinchona-alkaloid derivatives, gives chiral β-fluoro ketones with moderate to high levels of enantioselectivity (see scheme). Both enantiomers of the product could be obtained by using the appropriate catalyst.

    5. Bond Activation

      C[BOND]F Bond Activation with an Apparently Benign Ethynyl Dithiocarbamate, and Subsequent Fluoride Transfer Reactions (pages 12955–12957)

      Gaël Ung and Prof. Guy Bertrand

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201202292

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      F-act finding mission: Selective activation of the para C[BOND]F bonds of perfluorinated aromatic derivatives was achieved with a simple ethynyl dithiocarbamate. The resulting adducts can be used as non-ionic, anhydrous fluoride transfer reagents towards various electrophiles (see scheme).

    6. Domino Reactions

      Organocatalytic Aza-Michael–Michael Cascade Reactions: A Flexible Approach to 2,3,4-Trisubstituted Tetrahydroquinolines (pages 12958–12961)

      Dr. Zhen-Xin Jia, Dr. Yong-Chun Luo, Dr. Yao Wang, Liang Chen, Prof. Dr. Peng-Fei Xu and Prof. Dr. Binghe Wang

      Version of Record online: 23 SEP 2012 | DOI: 10.1002/chem.201201362

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      Cascading like dominos: An efficient and highly enantioselective synthesis of 2,3,4-trisubstituted tetrahydroquinolines through cascade aza-Michael–Michael reactions was developed. Tetrahydroquinolines were obtained in excellent yields, high enantioselectivities, and good diastereoselectivities, and could be easily transformed into ring-fused tetrahydroquinolines (see scheme).

    7. Hybrid Polyoxometalates

      Self-Buffering Hybrid Gold-Polyoxometalate Catalysts for the Catalytic Cyclization of Acid-Sensitive Substrates (pages 12962–12965)

      Nathalie Dupré, Dr. Christian Brazel, Prof. Louis Fensterbank, Prof. Max Malacria, Prof. Serge Thorimbert, Prof. Bernold Hasenknopf and Dr. Emmanuel Lacôte

      Version of Record online: 3 SEP 2012 | DOI: 10.1002/chem.201201007

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      Grafting of a gold complex to an organo-polyoxometalate delivers catalytically active bitopic hybrids. The gold end activates allenes, while the metal-oxide surface can capture protons (see scheme). The scope of the gold-catalyzed oxacyclization of allenols is expanded to highly sensitive tertiary benzylic alcohols.

    8. Asymmetric Catalysis

      Enantioselective Zinc-Mediated Conjugate Addition of Terminal Alkynes to Enones (pages 12966–12969)

      Prof. Dr. Gonzalo Blay, Dr. Luz Cardona, Prof. Dr. José R. Pedro and Amparo Sanz-Marco

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201201765

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      Zinc for conjugate alkynylation: The enantioselective conjugate addition of terminal alkynes to 2-arylidene-1,3-diketones in the presence of diethylzinc and a catalytic amount of (R)-VANOL has been developed. The reaction can be applied to different aromatic and heteroaromatic alkynes and enones, giving the expected products in good yield and with enantiomeric excesses up to 91 %. The products can be enantiomerically enriched up to 99 % ee by crystallization (see scheme).

    9. Magnetic Properties

      A Metal–Organic Framework as Attractive Cryogenic Magnetorefrigerant (pages 12970–12973)

      Romain Sibille, Dr. Thomas Mazet, Prof. Dr. Bernard Malaman and Prof. Dr. Michel François

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201200861

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      Magnetocaloric effect: A GdIII-based metal–organic framework (MOF) has an unprecedented large magnetocaloric effect around 2 K. It was shown to be an interesting magnetorefrigerant for ultralow-temperature applications, because it combines the advantages of molecular materials and the robustness of a framework with strong 3D chemical connections (see figure).

    10. Peptidomimetics

      Enaminone-Based Mimics of Extended and Hydrophilic α-Helices (pages 12974–12977)

      Prof. Marc J. Adler, Richard T. W. Scott and Prof. Andrew D. Hamilton

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201202120

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      Synthetic molecules capable of the mimicry of α-helices that are elongated and/or contain hydrophilic side chains have been largely elusive. However, the oligophenylenaminone structure can surmount both of these challenges (see scheme).

  6. Full Papers

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. News
    5. Concept
    6. Communications
    7. Full Papers
    1. Nanoparticles

      Platinum Nanoparticles Stabilized by Cucurbit[6]uril with Enhanced Catalytic Activity and Excellent Poisoning Tolerance for Methanol Electrooxidation (pages 12978–12985)

      Dr. Minna Cao, Dongshuang Wu, Dr. Shuiying Gao and Prof. Rong Cao

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201201817

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      Building tolerance: Three sub-10 nm platinum nanoparticles (PtNPs) with distinctive morphologies were developed by using cucurbit[6]uril (CB[6]) as stabilizing agent and support (see figure). Due to the presence of CB[6] and the unique structural features, the as-prepared PtNPs exhibited unprecedented catalytic activity and excellent poisoning tolerance ability toward methanol electrooxidation.

    2. Fluorescence

      Red-Emitting Rhodamines with Hydroxylated, Sulfonated, and Phosphorylated Dye Residues and Their Use in Fluorescence Nanoscopy (pages 12986–12998)

      Dr. Kirill Kolmakov, Dr. Christian A. Wurm, Dipl.-Ing. René Hennig, Dr. Erdmann Rapp, Prof. Stefan Jakobs, Dr. Vladimir N. Belov and Prof. Stefan W. Hell

      Version of Record online: 11 SEP 2012 | DOI: 10.1002/chem.201201168

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      A study in scarlet: Rhodamines that absorb at 621–637 nm and emit at 644–660 nm were prepared and used in fluorescence microscopy and nanoscopy. They are photostable and feature variable polarities and net charges, high stabilities of N-hydroxysuccinimidyl (NHS) esters, large fluorescence quantum yields in aqueous solutions, and antibody conjugates.

    3. Peptidomimetics

      Synthesis of Rhenium-Centric Reverse Turn Mimics (pages 12999–13007)

      Dr. Jennifer L. Hickey and Prof. Dr. Leonard G. Luyt

      Version of Record online: 3 SEP 2012 | DOI: 10.1002/chem.201201766

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      Redefining chemical space: Molecular scaffolds have been shown to facilitate and stabilise 2° structural turn elements, with a central core arranging functionality in a defined 3-dimensional orientation. By utilising a Re(CO)3+ centre (see figure), we have demonstrated that amino acid sequences can be assembled, reduced and coordinated on-resin, resulting in a diverse set of turn-based peptidomimetics.

    4. Microfluidics

      Hierarchical Supramolecular Spinning of Nanofibers in a Microfluidic Channel: Tuning Nanostructures at a Dynamic Interface (pages 13008–13017)

      Prof. Dr. Munenori Numata, Yusuke Takigami, Momoko Takayama, Tomohiro Kozawa and Naoya Hirose

      Version of Record online: 3 SEP 2012 | DOI: 10.1002/chem.201201300

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      You spin me right round: A new supramolecular system is described for the hierarchical organization of self-assembling polymers, which combines conventional supramolecular strategies with microfluidic science. By using this system, stable macroscopic polysaccharide strands with centimeter-scale lengths were created, in which polysaccharide nanofibers were assembled hierarchically in a supramolecular fashion by the dynamic flow (see figure).

    5. Crystal Engineering

      Central-Atom Size Effects on the Methyl Torsions of Group XIV Tetratolyls (pages 13018–13024)

      Dr. Maggie C. C. Ng, Dr. Jason B. Harper, Dr. Anton P. J. Stampfl, Prof. Gordon J. Kearley, Dr. Stéphane Rols and Prof. John A. Stride

      Version of Record online: 3 SEP 2012 | DOI: 10.1002/chem.201202105

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      Size matters! The size of the central atom in the Group XIV tetratolyls was shown to determine the solid-state structures courtesy of the effect that it has on the overall size of the molecules (see figure). Because the outer-most methyl groups enter into close intermolecular interactions (for the Si and Ge analogues), the structure is driven to lower symmetry; as a consequence, the smallest (C) and largest (Sn and Pb) analogues are isostructural.

    6. Magnetic Coupling

      Protonation of an Oxo-Bridged Diiron Unit Gives Two Different Iron Centers: Synthesis and Structure of a New Class of Diiron(III)-μ-hydroxo Bisporphyrins and the Control of Spin States by Using Counterions (pages 13025–13037)

      Susovan Bhowmik, Sudip Kumar Ghosh, Samar Layek, Prof. Harish Chandra Verma and Dr. Sankar Prasad Rath

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201201466

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      The core of the matter: A previously unknown family of diiron(III)-μ-hydroxo bisporphyrins in which two different spin states of Fe are stabilized in a single molecular framework, even though both cores have identical molecular structures, is presented. The spin states were found to be dependent on the counterion (see figure; X indicates the counterion).

    7. Gels

      Anion-Responsive Diguanidinium-Based Chiral Organogelators (pages 13038–13047)

      Dr. Julián Valero, Dr. Beatriu Escuder, Dr. Juan F. Miravet and Prof. Javier de Mendoza

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201200943

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      Self-expression: Stable chiral anion-responsive gels from bicyclic diguanidinium fragments readily form in apolar solvents (see picture). Chirality is expressed at the microscopic level, and racemic and meso forms yield weaker aggregates or simply no gels, respectively. Anion control of gelation allows a phase-selective anion-specific gelation of apolar organic liquids in the presence of salted aqueous solutions. Fully reversible sol-to-gel transitions by anion exchange are observed.

    8. Thin Films

      Does a Photocatalytic Synergy in an Anatase–Rutile TiO2 Composite Thin-Film Exist? (pages 13048–13058)

      Dr. Andreas Kafizas, Prof. Claire J. Carmalt and Prof. Ivan P. Parkin

      Version of Record online: 3 SEP 2012 | DOI: 10.1002/chem.201201859

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      Director's cut: Films with graded thickness and anatase–rutile phase were made by combinatorial APCVD. The photocatalytic activities of nearly 200 unique locations were evaluated and related to physical changes. This verified the standard photocatalytic model for anatase TiO2, in which electrons and holes reach the surface before recombining. Moreover, no evidence for photocatalytic synergy in anatase–rutile composites was found.

    9. Analytical Methods

      Attachment of Chloride Anion to Sugars: Mechanistic Investigation and Discovery of a New Dopant for Efficient Sugar Ionization/Detection in Mass Spectrometers (pages 13059–13067)

      Lemia Boutegrabet, Dr. Basem Kanawati , Dr. Istvan Gebefügi, Dr. Dominique Peyron, Prof. Philippe Cayot, Prof. Régis D. Gougeon and Dr. Philippe Schmitt-Kopplin 

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201103788

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      A new efficient ionization method for ultrahigh-resolution electrospray mass spectrometry of carbohydrates using aqueous HCl solutions has been developed. The formation of chlorinated anions [M+Cl] significantly enhances the detection sensitivity of sugars and glycosylated compounds compared with their deprotonated ionic forms (see figure).

    10. Mesoporous Materials

      Azobenzene Polyesters Used as Gate-Like Scaffolds in Nanoscopic Hybrid Systems (pages 13068–13078)

      Dr. Andrea Bernardos, Dr. Laura Mondragón, Dr. Irakli Javakhishvili, Núria Mas, Cristina de la Torre, Prof. Ramón Martínez-Máñez, Dr. Félix Sancenón, Prof. José M. Barat, Prof. Søren Hvilsted, Dr. Mar Orzaez, Dr. Enríque Pérez-Payá and Prof. Pedro Amorós

      Version of Record online: 24 AUG 2012 | DOI: 10.1002/chem.201200787

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      The gate way: A bio-controlled gated material has been prepared by the grafting of azobenzene-functionalised polyesters onto the pore outlets of a mesoporous support. The esterase-induced hydrolysis of the ester bond in the polyester moiety (see scheme) allows release to the bulk solution of a dye or cytotoxic drug entrapped in the pores of the hybrid material.

    11. Chiral Bis-Amides

      Supramolecular Chirality in Organo-, Hydro-, and Metallogels Derived from Bis-amides of L-(+)-Tartaric Acid: Formation of Highly Aligned 1D Silica Fibers and Evidence of 5-c Net SnS Topology in a Metallogel Network (pages 13079–13090)

      Uttam Kumar Das and Dr. Parthasarathi Dastidar

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201200871

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      Kept in suspense: A series of bis-tartaramides showed efficient ambidextrous gelling behavior (see scheme). The nanotubular gel network displayed by the bis-tartaramide derived from 3-pyridylamine (D-3-PyTA) was used as a template to synthesize highly aligned 1D fibrous silica from Si(OC2H5)4. It was also capable of forming coordination-polymer-based metallogels when treated with CuII/ZnII salts.

    12. Supramolecular Chemistry

      Heat-Induced Morphological Transformation of Supramolecular Nanostructures by Retro-Diels–Alder Reaction (pages 13091–13096)

      Prof. Dr. Masato Ikeda, Rika Ochi, Yu-shi Kurita, Prof. Dr. Darrin J. Pochan and Prof. Dr. Itaru Hamachi

      Version of Record online: 11 SEP 2012 | DOI: 10.1002/chem.201201670

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      The heat is on: We show that a morphological transformation from 2D nanosheets to a network of 1D nanofibers is triggered by heating (see figure), which induces molecular conversion of a bolaamphiphile to a hydrogelator by means of a retro-Diels–Alder reaction, thereby producing a new heat-set supramolecular hydrogel.

    13. Cycloaddition Reactions

      Direct Detection of Key Intermediates in Rhodium(I)-Catalyzed [2+2+2] Cycloadditions of Alkynes by ESI-MS (pages 13097–13107)

      Magda Parera, Dr. Anna Dachs, Prof. Dr. Miquel Solà, Dr. Anna Pla-Quintana and Prof. Dr. Anna Roglans

      Version of Record online: 30 AUG 2012 | DOI: 10.1002/chem.201200880

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      Detecting intermediates: The mechanism of the RhI-catalyzed [2+2+2] cycloaddition reaction was examined using ESI-MS (see scheme). All of the intermediates in the catalytic cycle were detected by ESI-MS for the first time and characterized by ESI-MS/MS. DFT was used to support the structural proposal made for the monoyne insertion intermediate.

    14. Enzyme Catalysis

      Lanosterol Biosynthesis: The Critical Role of the Methyl-29 Group of 2,3-Oxidosqualene for the Correct Folding of this Substrate and for the Construction of the Five-Membered D Ring (pages 13108–13116)

      Prof. Dr. Tsutomu Hoshino, Akifumi Chiba and Naomi Abe

      Version of Record online: 30 AUG 2012 | DOI: 10.1002/chem.201201779

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      Ringing in the changes: The incubation of 1 with porcine-liver cyclase afforded new nortriterpenes 2 and 3 with 6,6,6,6-fused tetracyclic skeletons, which were produced by chair-boat-chair-chair and chair-chair-boat-chair conformations, respectively (see scheme), thus indicating that the 29-methyl group is critical to the correct folding of oxidosqualene and to the formation of the five-membered D ring for lanosterol biosynthesis.

    15. Host–Guest Systems

      A Soft Copper(II) Porous Coordination Polymer with Unprecedented Aqua Bridge and Selective Adsorption Properties (pages 13117–13125)

      Elsa Quartapelle Procopio, Tomohiro Fukushima, Prof. Dr. Elisa Barea, Prof. Dr. Jorge A. R. Navarro, Prof. Dr. Satoshi Horike and Prof. Dr. Susumu Kitagawa

      Version of Record online: 30 AUG 2012 | DOI: 10.1002/chem.201201820

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      Water bridge: The plasticity of copper(II) ions and the presence of convergent active open-metal sites in the porous network confers bistability and adsorption selectivity towards gases and vapors of industrial and environmental interest (see figure).

    16. Synthetic Methods

      Synthesis of 3-Fluoropyrrolidines and 4-Fluoropyrrolidin-2-ones from Allylic Fluorides (pages 13126–13132)

      Lorraine E. Combettes, Dr. Marie Schuler, Rakesh Patel, Baltasar Bonillo, Dr. Barbara Odell, Dr. Amber L. Thompson, Dr. Tim D. W. Claridge and Prof. Véronique Gouverneur

      Version of Record online: 18 SEP 2012 | DOI: 10.1002/chem.201201576

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      The 5-exo-trig cyclisation of N-protected allylic fluorides leads to fluoropyrrolidin(on)es in yields up to 97 %. The fluorine substituent is an efficient stereodirecting group imposing a syn relationship with the newly formed iodomethylated stereogenic centre (see scheme). The striking similarities, with respect to stereocontrol, observed for allylic fluorides bearing O- and N-tosyl nucleophiles indicate that the cyclisations studied involve I2–π complexes with the fluorine adopting the inside position.

    17. NMR Spectroscopy

      Conformational Analysis of Fluorinated Pyrrolidines Using 19F–1H Scalar Couplings and Heteronuclear NOEs (pages 13133–13141)

      Lorraine E. Combettes, Philip Clausen-Thue, Dr. Michael A. King, Dr. Barbara Odell, Dr. Amber L. Thompson, Prof. Véronique Gouverneur and Dr. Tim D. W. Claridge

      Version of Record online: 18 SEP 2012 | DOI: 10.1002/chem.201201577

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      HOESY does it! 1D 19F–1H heteronuclear NOE experiments have been optimised for the study of small molecules and applied to investigate the conformations of fluorinated pyrrolidines in solution and the stabilising influence of the stereoelectronic fluorine gauche effect (see figure).

    18. Mesoporous Materials

      Electrochemical Design of Mesoporous Pt–Ru Alloy Films with Various Compositions toward Superior Electrocatalytic Performance (pages 13142–13148)

      Hongjing Wang, Dr. Masataka Imura, Dr. Yoshihiro Nemoto, Dr. Liang Wang, Dr. Hu Young Jeong, Dr. Tokihiko Yokoshima, Prof. Osamu Terasaki and Prof. Yusuke Yamauchi

      Version of Record online: 22 AUG 2012 | DOI: 10.1002/chem.201201964

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      Electrochemical deposition: Mesoporous Pt–Ru alloy films with various compositions were synthesized by electrochemical plating in an aqueous surfactant solution. The Ru content in the films could be controlled from 0 to 13 at % by changing the precursor compositions. These films showed superior electrocatalytic activity for the methanol oxidation reaction.

    19. Iridium Carbenes

      Reversible Double C[BOND]H Bond Activation of Linear and Cyclic Ethers To Form Iridium Carbenes (pages 13149–13159)

      Dr. Jose E. V. Valpuesta, Dr. Eleuterio Álvarez, Dr. Joaquín López-Serrano, Dr. Celia Maya and Prof. Ernesto Carmona

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201201883

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      An active role: Linear and cyclic ethers undergo double C[BOND]H bond activation promoted by the Tptol′Ir(C6H5)2 (Tptol′=cyclometalated hydrotris(3-p-tolylpyrazol-1-yl)borate ligand) metal fragment. The formation of the resulting carbene hydrides is shown to be reversible for some ethers, including dimethyl and diethyl ethers (see scheme). The p-tolyl fragments of the metalated Tptol′ ligands may play a role in the C[BOND]H activation mechanism.

    20. Tautomerism

      Tautomerization in 2,7,12,17-Tetraphenylporphycene and 9-Amino-2,7,12,17-tetraphenylporphycene: Influence of Asymmetry on the Direction of the Transition Moment (pages 13160–13167)

      Dr. Piotr Fita, Maria Pszona, Grażyna Orzanowska, Dr. David Sánchez-García, Prof. Dr. Santi Nonell, Prof. Dr. Eric Vauthey and Prof. Dr. Jacek Waluk

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201201432

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      Hydrogen transfer and transition moments: Intramolecular double hydrogen exchange in asymmetrically substituted porphycene occurs with a similar rate to that in analogous symmetrical derivatives but is not accompanied by a large change in the direction of the transition moment. This result is explained by an analysis of the molecular orbitals that are involved in two lowest-energy transitions (see figure).

    21. Chirality

      Donor-Induced Helical Inversion of 1,1′-Binaphthyl Connecting with Two Molybdenum Complexes (pages 13168–13172)

      Dr. Li Ma, Dr. Rizhe Jin, Dr. Zheng Bian, Dr. Chuanqing Kang, Yu Chen, Prof. Jingwei Xu and Prof. Lianxun Gao

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201201671

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      Finding the critical angle: An atropisomeric biaryl molecule with a given absolute configuration could present two opposite helical conformations through rotation around a C[BOND]C single bond. Such helical inversion behavior of 1,1′-binaphthyl connecting two molybdenum complexes through intervention from a donor is reported (see scheme).

    22. Enzyme Catalysis

      You have full text access to this OnlineOpen article
      Inverting the Regioselectivity of the Berberine Bridge Enzyme by Employing Customized Fluorine-Containing Substrates (pages 13173–13179)

      Dr. Verena Resch, Horst Lechner, Dr. Joerg H. Schrittwieser, Dr. Silvia Wallner, Prof. Dr. Karl Gruber, Prof. Dr. Peter Macheroux and Prof. Dr. Wolfgang Kroutil

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201201895

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      Custom-made substrates: Employing customized substrates with a fluoro atom at the normally preferred reaction site switched the regioselectivity of the berberine-bridged enzyme. With this strategy, it was possible to get access to (S)-11-hydroxy-functionalized berbines in an asymmetric fashion by using the wild-type enzyme (see scheme).

    23. Nanostructures

      Controlling the Regioselectivity of the Hydrosilylation Reaction in Carbon Nanoreactors (pages 13180–13187)

      William A. Solomonsz, Dr. Graham A. Rance, Dr. Mikhail Suyetin, Alessandro La Torre, Dr. Elena Bichoutskaia and Prof. Dr. Andrei N. Khlobystov

      Version of Record online: 11 SEP 2012 | DOI: 10.1002/chem.201201542

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      Nanoscale reaction vessels: Carbon nanoreactors are prepared by encapsulating catalytic Rh or RhPt nanoparticles in hollow graphitised nanofibres. Inside the nanoreactors, the pathways of the hydrosilylation reactions differ from those on the surface of nanofibres or in the bulk phase (see scheme).

    24. Fluorescent Labels

      Angular Benzoperylenetetracarboxylic Bisimides (pages 13188–13194)

      Prof. Dr. Heinz Langhals, Dr. Bernd Böck, M. Sc. Tanja Schmid and Alexey Marchuk

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201103221

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      Two angular rings: Benzoperylene derivatives with two angularly attached dicarboxylic imide rings, which were prepared by the Diels–Alder reaction, are strongly fluorescent (see figure) and were applied both for fluorescence labeling (e.g., enzymes) and as components in FRET and PET systems.

    25. Polyoxometalates

      Hybrid Polyoxotungstates as Functional Comonomers in New Cross-Linked Catalytic Polymers for Sustainable Oxidation with Hydrogen Peroxide (pages 13195–13202)

      Dr. Mauro Carraro, Dr. Giulia Fiorani, Dr. Lorenzo Mognon, Dr. Francesca Caneva, Dr. Martino Gardan, Dr. Chiara Maccato and Dr. Marcella Bonchio

      Version of Record online: 27 AUG 2012 | DOI: 10.1002/chem.201201849

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      Oxidative desulfurization with hybrid polymer catalysts: Polymerizable organic–inorganic monomers with the formula [{CH2[DOUBLE BOND]CH(CH2)6Si}xOySiWwOz]4− [x=2, w=11, y=1, z=39; x=2, w=10, y=1, z=36; and x=4, w=9, y=3, z=34] were used to prepare hybrid porous copolymers with methyl methacrylate and ethylene glycol dimethacrylate. These functional materials catalyze the selective oxidation of organic sulfides with aqueous hydrogen peroxide in biphasic CH3CN/n-octane systems. The catalyst system shows potential for oxidation and removal of dibenzothiophene, a well-known gasoline contaminant (see figure).

    26. Gold Clusters

      Observable Structures of Small Neutral and Anionic Gold Clusters (pages 13203–13207)

      Prof. Dr. Han Myoung Lee and Prof. Dr. Kwang S. Kim

      Version of Record online: 31 AUG 2012 | DOI: 10.1002/chem.201200771

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      Intriguing structures with dangling atoms are stable up to n=4 for neutral gold clusters Aun and up to n=7 for anionic clusters Aun according to ab initio calculations (see figure), which is in good agreement with photoelectron spectroscopic data.

    27. Dodecaborates

      From an Icosahedron to a Plane: Flattening Dodecaiodo-dodecaborate by Successive Stripping of Iodine (pages 13208–13212)

      Dr. Pau Farràs, Dr. Nina Vankova, Lei Liu Zeonjuk, Jonas Warneke, Dr. Thomas Dülcks, Prof. Dr. Thomas Heine, Prof. Dr. Clara Viñas, Prof. Dr. Francesc Teixidor and Prof. Dr. Detlef Gabel

      Version of Record online: 7 SEP 2012 | DOI: 10.1002/chem.201200828

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      Flat out: When icosahedral B12I122− is fragmented in mass spectrometry and its iodine atoms are stripped off one by one, it eventually forms a planar B12 unit (see figure). This transition occurs when seven to five iodine atoms remain.

    28. Nanostructures

      Metastable Tetragonal Cu2Se Hyperbranched Structures: Large-Scale Preparation and Tunable Electrical and Optical Response Regulated by Phase Conversion (pages 13213–13221)

      Dr. Jinbao Zhu, Qiuyang Li, Liangfei Bai, Yongfu Sun, Min Zhou and Prof. Yi Xie

      Version of Record online: 3 SEP 2012 | DOI: 10.1002/chem.201200899

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      Metastable Cu2Se: Metastable β-Cu2Se hyperbranched structures have been successfully synthesized for the first time by a simple large-scale hydrothermal approach. The hyperbranched structures exhibit tunable electrical and optical properties as a result of regulated solid-state phase conversion (see figure).

    29. Organocatalysis

      Enantioselective Organocatalytic One-Pot Amination/aza-Michael/Aldol Condensation Reaction Sequence: Synthesis of 3-Pyrrolines with a Quaternary Stereocenter (pages 13222–13225)

      Alaric Desmarchelier, Dr. Vincent Coeffard, Dr. Xavier Moreau and Prof. Christine Greck

      Version of Record online: 27 AUG 2012 | DOI: 10.1002/chem.201202024

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      Expect the unexpected: Primary amine-catalyzed direct conversion of α,α-disubstituted aldehydes into 3-pyrrolines with a quaternary stereocenter is reported. The sequence involves an α-amination, an aza-Michael addition of hydrazine, an aldol condensation and proceeds with good yields and excellent levels of enantioselectivity (see scheme).

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