Chemistry - A European Journal

Cover image for Vol. 18 Issue 20

May 14, 2012

Volume 18, Issue 20

Pages 6105–6399

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      Cover Picture: Electronic Structure and Aromaticity of Graphene Nanoribbons (Chem. Eur. J. 20/2012) (page 6105)

      Dr. Francisco J. Martín-Martínez, Dr. Stijn Fias, Dr. Gregory Van Lier, Prof. Frank De Proft and Prof. Paul Geerlings

      Article first published online: 3 MAY 2012 | DOI: 10.1002/chem.201290078

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      The electronic structure and aromaticityof graphene nanoribbons and carbon nanotubes has been analyzed and color coded. The three distinct classes of aromaticity patterns found for armchair graphene nanoribbons (Kekulé, Clar, incomplete-Clar, or i-Clar) are related to the periodicity in the band gap. The appearance of such distinct aromaticity distribution is explained within the framework of the Clar's sextet theory. For more details, see the Full Paper by F. J. Martín-Martínez et al. on page 6183 ff.

  2. Inside Cover

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    1. Inside Cover: Cyclic RGD Peptidomimetics Containing Bifunctional Diketopiperazine Scaffolds as New Potent Integrin Ligands (Chem. Eur. J. 20/2012) (page 6106)

      Mattia Marchini, Michele Mingozzi, Raffaele Colombo, Ileana Guzzetti, Dr. Laura Belvisi, Dr. Francesca Vasile, Dr. Donatella Potenza, Prof. Dr. Umberto Piarulli, Dr. Daniela Arosio and Prof. Dr. Cesare Gennari

      Article first published online: 3 MAY 2012 | DOI: 10.1002/chem.201290079

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      Cyclo-[DKP-RGD] peptidomimetics obtained by cyclization of bifunctional diketopiperazines (DKP) with RGD, inhibit vitronectin binding to integrins αvβ3 and αvβ5 at low nanomolar concentration. Conformational studies (NMR spectroscopy and calculations) reveal that the highest affinity ligands display an extended RGD arrangement, in which the carboxylate and guanidinium groups act like an electrostatic clamp, interacting with charged regions of the receptor binding site. For more details see the Full Paper by C. Gennari et al. on page 6195 ff.

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    1. Graphical Abstract: Chem. Eur. J. 20/2012 (pages 6109–6118)

      Article first published online: 3 MAY 2012 | DOI: 10.1002/chem.201290080

  4. News

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  5. Communications

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    1. Copper Catalysis

      Copper-Catalyzed Formation of C[BOND]O Bonds by Direct α-C[BOND]H Bond Activation of Ethers Using Stoichiometric Amounts of Peroxide in Batch and Continuous-Flow Formats (pages 6124–6128)

      G. Sathish Kumar, Bartholomäus Pieber, Dr. K. Rajender Reddy and Prof. Dr. C. Oliver Kappe

      Article first published online: 11 APR 2012 | DOI: 10.1002/chem.201200815

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      Peroxides and ethers in flow: 2-Carbonyl-substituted phenols and β-ketoesters react safely with ethers in a microreactor environment using a copper catalyst and an organic peroxide (TBHP). This protocol results in unsymmetrical acetal scaffolds not easily available otherwise (see scheme).

    2. Enzyme Catalysis

      Dynamic Asymmetric Hemithioacetal Transformation by Lipase-Catalyzed γ-Lactonization: In Situ Tandem Formation of 1,3-Oxathiolan-5-one Derivatives (pages 6129–6132)

      Dr. Morakot Sakulsombat, Yan Zhang and Prof. Olof Ramström

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201102139

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      Dynamic hemithioacetal systems were efficiently generated in organic solvents and subsequently allowed to react with a range of lipases. This resulted in direct, dynamic asymmetric transformation of the systems, leading to optically active 1,3-oxathiolan-5-one products. The tandem process identified lipase-catalyzed lactonization as a useful method for the resolution of optimal constituents with high chemo- and stereoselectivities.

    3. Homogeneous Catalysis

      Silver Triflate Catalyzed Tandem Heterocyclization/Alkynylation of 1-((2-Tosylamino)aryl)but-2-yne-1,4-diols to 2-Alkynyl Indoles (pages 6133–6137)

      Srinivasa Reddy Mothe, Dr. Prasath Kothandaraman, Sherman Jun Liang Lauw, Samuel Ming Wei Chin and Prof. Dr. Philip Wai Hong Chan

      Article first published online: 18 APR 2012 | DOI: 10.1002/chem.201200578

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      Don't cross me! 2-Alkynyl indoles were prepared efficiently by the AgOTf-catalyzed tandem heterocyclization/alkynylation of 1-(2-tosylamino)aryl)but-2-yne-1,4-diols under mild conditions (see scheme). The attractiveness of this approach lies in the fact that both the indole ring and alkyne side chain of the N-heterocycle are sequentially formed from low cost, readily available, and ecologically benign starting materials. It also provides the first route to this synthetically valuable class of compounds that is not based on a cross-coupling strategy.

    4. Domino Reactions

      Winding up Alkynes: A Pd-Catalyzed Tandem-Domino Reaction to Chiral Biphenyls (pages 6138–6141)

      Dipl.-Chem. Markus Leibeling and Dr. Daniel B. Werz

      Article first published online: 16 APR 2012 | DOI: 10.1002/chem.201200175

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      Wrap it up! An intramolecular Pd-catalyzed tandem-domino process leading to highly sterically encumbered biphenyls is reported. The chirality of the newly formed axis is induced by the configuration of the carbohydrate backbone.

    5. Cyclopropanes

      Nickel-Catalyzed Regio- and Stereoselective Reductive Coupling between Methylenecyclopropanes, Aldehydes, and Triethylborane with Retention of the Cyclopropane Ring (pages 6142–6146)

      Dr. Kenichi Ogata, Daisuke Shimada and Prof. Dr. Shin-ichi Fukuzawa

      Article first published online: 16 APR 2012 | DOI: 10.1002/chem.201200271

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      Running rings: The first regio- and stereoselective reductive coupling between methylenecyclopropanes, aldehydes, and triethylborane with retention of the cyclopropane ring was achieved using a nickel–phosphine catalyst (see scheme). The reductive coupling reaction constructed a stereo-defined cyclopropane ring with formation of a quaternary stereogenic carbon center.

    6. Heterogeneous Catalysis

      Room Temperature Aerobic Oxidation of Amines by a Nanocrystalline Ruthenium Oxide Pyrochlore Nafion Composite Catalyst (pages 6147–6151)

      Shanmuganathan Venkatesan, Prof. Dr. Annamalai Senthil Kumar, Dr. Jyh-Fu Lee, Dr. Ting-Shan Chan and Prof. Dr. Jyh-Myng Zen

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201103913

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      The aerobic oxidation of primary amines to their respective nitriles has been carried out at room temperature using a highly reusable nanocrystalline ruthenium oxide pyrochlore Nafion composite catalyst (see figure).

    7. Organocatalysis

      Highly Enantioselective Epoxidation Catalyzed by Cinchona Thioureas: Synthesis of Functionalized Terminal Epoxides Bearing a Quaternary Stereogenic Center (pages 6152–6157)

      Dr. Alessio Russo, Gerardina Galdi, Dr. Gianluca Croce and Prof. Dr. Alessandra Lattanzi

      Article first published online: 18 APR 2012 | DOI: 10.1002/chem.201200500

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      A brilliant debut! Cinchona thioureas have been reported for the first time as catalysts in the area of asymmetric oxidations. They efficiently promote an unprecedented highly enantioselective epoxidation of deactivated 1,1-disubstituted alkenes to terminal epoxides containing a quaternary stereogenic center (see scheme).

    8. Oxidative Cross-Coupling

      Palladium(II)-Catalyzed Oxidative C[BOND]H/C[BOND]H Cross-Coupling between Two Structurally Similar Azoles (pages 6158–6162)

      Jiaxing Dong, Yumin Huang, Xurong Qin, Yangyang Cheng, Jing Hao, Danyang Wan, Wei Li, Xingyan Liu and Prof. Dr. Jingsong You

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201103813

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      Power of two: A widely functional-group tolerant, selective and rapid oxidative cross-coupling between two structurally similar azoles has been carried out by using a palladium/copper co-catalytic twofold C[BOND]H activation method (see scheme).

    9. Polyoxometalates

      {W48} Ring Opening: Fe16-Containing, Ln4-Stabilized 49-Tungsto-8-Phosphate Open Wheel [Fe16O2(OH)23(H2O)9(P8W49O189)Ln4(H2O)20]11− (pages 6163–6166)

      Dr. Amal H. Ismail, Dr. Bassem S. Bassil, Ghada H. Yassin, Dr. Bineta Keita and Prof. Ulrich Kortz

      Article first published online: 18 APR 2012 | DOI: 10.1002/chem.201200963

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      Wheely: For the first time and very unexpectedly, a rupture of the very stable {P8W48} wheel was observed in aqueous solution at pH 4 and 80 °C in the presence of FeIII, EuIII/GdIII, and H2O2. This inorganic ring opening is unprecedented in polyoxometalate chemistry.

    10. 3 d Metal Ions in Highly Unusual Eight-Coordination: The Phosphate-Capped Dodecapalladate(II) Nanocube (pages 6167–6171)

      Dr. Maria Barsukova-Stuckart, Dr. Natalya V. Izarova, Ryan Barrett, Zhenxing Wang, Dr. Johan van Tol, Prof. Harold W. Kroto, Prof. Naresh S. Dalal, Dr. Bineta Keita, Prof. Detlef Heller and Prof. Ulrich Kortz

      Article first published online: 13 APR 2012 | DOI: 10.1002/chem.201200060

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      Trapped in a noble cube: A novel family of noble metalates has been discovered in which a 3d metal ion M (M=MnII, FeIII, CoII, CuII, ZnII) is encapsulated by a 12 palladium–oxo cage {Pd12O32}, which is capped by eight phosphate groups. Such discrete nanocubes were further investigated by EPR spectroscopy, electrochemistry, and in homogeneous hydrogenation catalysis.

  6. Full Papers

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    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
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    1. Lewis Acid Chemistry

      Strong Lewis Acids of Air-Stable Metallocene Bis(perfluorooctanesulfonate)s as High-Efficiency Catalysts for Carbonyl-Group Transformation Reactions (pages 6172–6182)

      Dr. Renhua Qiu, Prof. Dr. Xinhua Xu, Dr. Lifeng Peng, Dr. Yalei Zhao, Dr. Ningbo Li and Prof. Dr. Shuangfeng Yin

      Article first published online: 13 APR 2012 | DOI: 10.1002/chem.201103874

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      Green catalysis: The high Lewis acidic, air- and thermal-stable cationic metallocene Lewis acids [M(Cp)2][OSO2C8F17]2 (M=Zr, Ti) show excellent catalytic efficiency in carbonyl-compound transformation reactions, such as the Mannich reaction, the Mukaiyama aldol reaction, allylation of aldehydes, the Friedel–Crafts acylation of alkylaromatic ethers, and cyclotrimerization of ketones. Moreover, the complexes possess good reusability.

    2. Graphene

      Electronic Structure and Aromaticity of Graphene Nanoribbons (pages 6183–6194)

      Dr. Francisco J. Martín-Martínez, Dr. Stijn Fias, Dr. Gregory Van Lier, Prof. Frank De Proft and Prof. Paul Geerlings

      Article first published online: 19 APR 2012 | DOI: 10.1002/chem.201103977

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      Periodic patterns! The three distinct classes of aromaticity patterns found for armchair graphene nanoribbons, namely Kekulé, Clar and incomplete-Clar, have been analysed and color coded (see figure) with the six-center index and the mean bond length geometry descriptor. These patterns are explained within the framework of the Clar's sextet theory, as a combination of different Clar configurations. The periodicity of the patterns depending on the width of the ribbon is closely related to the periodicity in the band gap.

    3. Peptidomimetics

      Cyclic RGD Peptidomimetics Containing Bifunctional Diketopiperazine Scaffolds as New Potent Integrin Ligands (pages 6195–6207)

      Mattia Marchini, Michele Mingozzi, Raffaele Colombo, Ileana Guzzetti, Dr. Laura Belvisi, Dr. Francesca Vasile, Dr. Donatella Potenza, Prof. Dr. Umberto Piarulli, Dr. Daniela Arosio and Prof. Dr. Cesare Gennari

      Article first published online: 19 APR 2012 | DOI: 10.1002/chem.201200457

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      A perfect fit: Shown here is the docking best pose of a subnanomolar αvβ3 integrin ligand cyclo-DKP-RGD (atom color tube representation) into the receptor binding pocket (green surface). The extended RGD conformation of the ligand permits all the important interactions with the extracellular domain of the αvβ3 integrin. The metal ion in the MIDAS region is represented by a magenta sphere.

    4. Diazaporphyrins

      Nickel(II) and Copper(II) Complexes of β-Unsubstituted 5,15-Diazaporphyrins and Pyridazine-Fused Diazacorrinoids: Metal–Template Syntheses and Peripheral Functionalizations (pages 6208–6216)

      Prof. Dr. Yoshihiro Matano, Tarou Shibano, Prof. Dr. Haruyuki Nakano and Prof. Dr. Hiroshi Imahori

      Article first published online: 30 MAR 2012 | DOI: 10.1002/chem.201200463

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      Highly peripheral: Nickel(II) and copper(II) complexes of β-unsubstituted diazaporphyrins and pyridazine-fused diazacorrinoids were synthesized by using the metal–template method, and their structures and optical/electrochemical properties were investigated. The regioselective functionalizations at the periphery afforded highly conjugated diazaporphyrin and diazacorrinoid π systems (see scheme).

    5. Cyclotrimerization

      DFT Studies on Cobalt-Catalyzed Cyclotrimerization Reactions: The Mechanism and Origin of Reaction Improvement under Microwave Irradiation (pages 6217–6224)

      Antonio M. Rodriguez, Cristina Cebrián, Dr. Pilar Prieto, Dr. José Ignacio García, Prof. Antonio de la Hoz and Prof. Ángel Díaz-Ortiz

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201103560

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      Microwave, macro effect: A DFT computational mechanistic study has been carried out on the [2+2+2] cyclotrimerization of a diyne with benzonitrile catalyzed by a Co complex. The beneficial role of microwave activation has also been studied (see scheme). Among other things, microwave irradiation can decrease the catalytic induction period through thermal effects.

    6. Molecular Modeling

      From Composites to Solid Solutions: Modeling of Ionic Conductivity in the CaF2–BaF2 System (pages 6225–6229)

      Prof. Dr. Dirk Zahn, Prof. Dr. Paul Heitjans and Prof. Dr. Joachim Maier

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201102410

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      Catwalk modeling: The effects of ion conductors in solid solutions can be understood as the atomistic limit of interfacial charge-transfer at hetero-interfaces, and thus reflect the transition from heterogeneous (higher-dimensional) to homogeneous (zero-dimensional) doping.

    7. Host–Guest Systems

      Ion-Pair Recognition by a Heteroditopic Triazole-Containing Receptor (pages 6230–6237)

      Simon C. Picot, Benjamin R. Mullaney and Prof. Paul D. Beer

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201200251

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      Two-timing triazole: A new heteroditopic calix[4]diquinone triazole containing receptor that recognises both cations and anions through Lewis base and C[BOND]H hydrogen-bonding modes of the triazole motif, respectively, has been prepared (see figure). The receptor cooperatively binds cation (Na+, K+, NH4+)/halide ion-pair species in an aqueous solvent mixture. The dual cation/anion binding role of the receptor's triazole groups is further demonstrated by X-ray crystallography.

    8. Antibiotics

      Thiols Screened by the Neocarzinostatin Protein for Preserving or Detoxifying its Bound Enediyne Antibiotic (pages 6238–6249)

      Hung-Wen Chi, Chun-Chi Huang and Prof. Der-Hang Chin

      Article first published online: 30 MAR 2012 | DOI: 10.1002/chem.201102825

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      Antibiotic protection and detoxification! Enediyne antibiotic NCS is synthesized by S. carzinostaticus in the form of a complex of apoNCS and NCS-C. Unbound NCS-C is inactivated by all thiols in living systems. ApoNCS plays two critical roles by using D33 and D99 to screen thiols: it preserves the secreted NCS-C by rejecting the ubiquitous GSH for survival and detoxifies NCS-C by accepting the cell-produced neutral mycothiol for self-resistance (see figure).

    9. Glycoclusters

      Rational Design and Synthesis of Optimized Glycoclusters for Multivalent Lectin–Carbohydrate Interactions: Influence of the Linker Arm (pages 6250–6263)

      Dr. Samy Cecioni, Dr. Jean-Pierre Praly, Dr. Susan E. Matthews, Dr. Michaela Wimmerová, Dr. Anne Imberty and Dr. Sébastien Vidal

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201200010

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      Library binding: A library of 18 tetravalent glycoclusters was synthesized from three structurally modified triethyleneglycol analogues that incorporate amide moiety(ies) and/or a phenyl ring. Binding to PA-IL (the LecA lectin from the opportunistic pathogen Pseudomonas aeruginosa) was determined by several methods. Among other things, this study revealed unprecedented affinities for one of the monovalent probes (see figure).

    10. Natural Products

      Sulfangolids, Macrolide Sulfate Esters from Sorangium cellulosum (pages 6264–6271)

      Dr. Wiebke Zander, Dr. Herbert Irschik, Dr. Hermann Augustiniak, Dr. Martina Herrmann, Dr. Rolf Jansen, Dipl.-Ing. Heinrich Steinmetz, Dr. Klaus Gerth, Dipl.-Ing. Wolfgang Kessler, Prof. Dr. Markus Kalesse, Prof. Dr. Gerhard Höfle and Prof. Dr. Rolf Müller

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201100851

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      On the count of four: Four sulfate ester containing metabolites and the structural related sulfate-free analogue kulkenon were isolated from Sorangium cellulosum. Following their structure elucidation, the relative configuration of the hemiketal-derivative sulfangolid C was determined by NMR spectroscopy combined with molecular modelling. In addition, the biosynthetic precursors of sulfangolid C were studied by feeding experiments with 13C-labelled precursors.

    11. Intermetallic Phases

      Structural Transformation with “Negative Volume Expansion”: Chemical Bonding and Physical Behavior of TiGePt (pages 6272–6283)

      S.-V. Ackerbauer, Dr. A. Senyshyn, Dr. H. Borrmann, Dr. U. Burkhardt, Dr. A. Ormeci, Dr. H. Rosner, Dr. W. Schnelle, Dr. M. Gamża, Dr. R. Gumeniuk, Dr. R. Ramlau, Dr. E. Bischoff, Prof. Dr. J. C. Schuster, Prof. Dr. F. Weitzer, Dr. A. Leithe-Jasper, Prof. Dr. L. H. Tjeng and Prof. Yu. Grin

      Article first published online: 29 MAR 2012 | DOI: 10.1002/chem.201102401

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      Negative volume expansion: An experimental and theoretical study reveals the new ternary intermetallic compound TiGePt exhibiting two modifications: Below 885 °C it crystallizes in the cubic MgAgAs-type (LT) structure, and at elevated temperatures it appears in the TiNiSi-type (HT) structure. The LT[RIGHTWARDS ARROW]HT transition is accompanied by a huge volume reduction of about 10 % (see figure).

    12. Electrochemistry

      Electrochemically Active Cross-Linking Reaction for Fluorescent Labeling of Aliphatic Alkenes (pages 6284–6288)

      Dr. Shokaku Kim, Kumi Hirose, Jumpei Uematsu, Yuzuru Mikami and Prof. Dr. Kazuhiro Chiba

      Article first published online: 20 MAR 2012 | DOI: 10.1002/chem.201103630

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      A valuable tool: Cross-linking reactions serve as a valuable tool for the integration of two or more functionalities or properties, but the application of electrochemical synthesis to cross-linking reactions for insoluble species is restricted. An electrochemically active cross-linking reaction for fluorescent labeling of alkene-modified insoluble targets is thus described (see figure).

    13. Complex Chemistry

      Heteroleptic Silylamido Phenolate Complexes of Calcium and the Larger Alkaline Earth Metals: β-Agostic Ae⋅⋅⋅Si[BOND]H Stabilization and Activity in the Ring-Opening Polymerization of L-Lactide (pages 6289–6301)

      Dr. Bo Liu, Dr. Thierry Roisnel, Jean-Paul Guégan, Prof. Jean-François Carpentier and Dr. Yann Sarazin

      Article first published online: 11 APR 2012 | DOI: 10.1002/chem.201103666

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      Alkaline earth metals at work: A general route to heteroleptic phenolate–amido complexes of the large alkaline earth metals stabilized against ligand scrambling by internal β-agostic Ae⋅⋅⋅H[BOND]Si (Ae=alkaline earth metal) interactions is presented. All factors governing the high activity of these Ca-, Sr-, and Ba-based catalysts in the (immortal) ring-opening polymerization of L-lactide have been investigated to allow for rational catalyst development (see scheme).

    14. Homogeneous Catalysis

      Ruthenium-Catalyzed Functionalization of Pyrroles and Indoles with Propargyl Alcohols (pages 6302–6308)

      Nora Thies, Dr. Cristian G. Hrib and Prof. Dr. Edgar Haak

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201200188

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      Multi-talented catalyst: Ruthenium(0) complexes containing redox-active cyclopentadienone ligands catalyze highly selective transformations of unsaturated alcohols through different modes of activation (see scheme). Several atom-economic processes leading to alkylation, annulation, or propargylation of pyrroles or indoles with propargyl alcohols by using a single pre-catalyst and mechanistic studies regarding the catalytic cycles are reported.

    15. Enzyme Catalysis

      How Is Methane Formed and Oxidized Reversibly When Catalyzed by Ni-Containing Methyl-Coenzyme M Reductase? (pages 6309–6315)

      Dr. Shi-Lu Chen, Prof. Dr. Margareta R. A. Blomberg and Prof. Dr. Per E. M. Siegbahn

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201200274

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      Which leads Me to methane? Reversible methane formation and oxidation catalyzed by methyl-coenzyme M reductase (MCR) has been investigated using the B3LYP functional with dispersion effects included. The calculations indicate that the MCR reaction proceeds via a methyl radical and a Ni-S(CoM) intermediate (see scheme).

    16. Gold Chemistry

      Gold(I) Styrylbenzene, Distyrylbenzene, and Distyrylnaphthalene Complexes: High Emission Quantum Yields at Room Temperature (pages 6316–6327)

      Dr. Lei Gao, Daniel S. Niedzwiecki, Nihal Deligonul, Matthias Zeller, Allen D. Hunter and Prof. Thomas G. Gray

      Article first published online: 30 MAR 2012 | DOI: 10.1002/chem.201102502

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      Gold rush! Gold(I) styrylbenzene, distyrylbenzene, and distyrylnaphthalene complexes were synthesized and characterized. The syntheses of these compounds were verified by NMR spectroscopy, HR-MS, and X-ray crystallography. As the conjugation length increases, the color of the solid compounds intensifies. Fluorescence quantum yields vary with structure. Time-dependent density-functional theory calculations indicate that the emission of these compounds derives from the conjugated aromatic moiety (see figure).

    17. Heterogeneous Organocatalysis

      4-(N,N-Dimethylamino)pyridine-Embedded Nanoporous Conjugated Polymer as a Highly Active Heterogeneous Organocatalyst (pages 6328–6334)

      Dr. Yuan Zhang, Yong Zhang, Ya Lei Sun, Dr. Xin Du, Dr. Jiao Yi Shi, Wei David Wang and Prof. Dr. Wei Wang

      Article first published online: 29 MAR 2012 | DOI: 10.1002/chem.201103028

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      Nanoporous catalyst: DMAP-NCP, a new network nanoporous conjugated polymer containing 4-(N,N-dimethylamino)pyridine catalytic moieties, has been constructed by the “bottom-up” strategy. It shows excellent activity and recyclability in the acylation of alcohols and phenols, even under neat and continuous-flow conditions (see figure). This study demonstrates the possibility of using DMAP-NCP as a robust and effective heterogeneous catalyst, especially for practical applications on a large scale.

    18. Raman Spectroscopy

      Selective and Sensitive Recognition of Cu2+ in an Aqueous Medium: A Surface-Enhanced Raman Scattering (SERS)-Based Analysis with a Low-Cost Raman Reporter (pages 6335–6342)

      Sougata Sarkar, Mukul Pradhan, Arun Kumar Sinha, Mrinmoyee Basu and Prof. Tarasankar Pal

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201103458

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      Being selective: Surface-enhanced Raman scattering (SERS) of a Raman reporter, 2-mercaptobenzimidazole (MBIm), over gold nanoparticles has been observed to be perturbed exclusively in the presence of Cu2+ ions in solution (see figure). Other common metal ions cannot cause this change in the SERS profile. With MBIm, a SERS-supportive Cu2+ detection protocol in solution emerges. A theoretical study also substantiates our experimental results.

    19. Solar Cells

      Convergent Synthesis of Near-Infrared Absorbing, “Push–Pull”, Bisthiophene-Substituted, Zinc(II) Phthalocyanines and their Application in Dye-Sensitized Solar Cells (pages 6343–6348)

      Mine Ince, François Cardinali, Jun-Ho Yum , M. Victoria Martínez-Díaz, Mohammad K. Nazeeruddin, Michael Grätzel and Tomás Torres

      Article first published online: 30 MAR 2012 | DOI: 10.1002/chem.201200020

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      Extended sensitizers: Highly π-conjugated, panchromatic, carboxyphthalocyanine dyes have been synthesized by a convergent approach using carboxytriiodo–ZnPc as a precursor (see scheme). These molecules have been tested as sensitizers in dye-sensitized solar cells and gave efficiencies close to 3 %.

    20. Asymmetric Synthesis

      Enantiomerically Pure Phosphaalkene–Oxazolines (PhAk-Ox): Synthesis, Scope and Copolymerization with Styrene (pages 6349–6359)

      Julien Dugal-Tessier, Spencer C. Serin, Emmanuel B. Castillo-Contreras, Dr. Eamonn D. Conrad, Prof. Dr. Gregory R. Dake and Prof. Dr. Derek P. Gates

      Article first published online: 4 APR 2012 | DOI: 10.1002/chem.201103887

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      Strong as an Ox: A synthetic strategy to form compounds with a P[DOUBLE BOND]C bond and an enantiomerically pure oxazoline moiety (PhAk-Ox) is reported. The methodology is modular and permits the fine tuning of steric and electronic properties. The radical-initiated copolymerization of PhAk-Ox and styrene gives functional phosphine-containing chiral copolymers (see scheme).

    21. Photocatalysis

      New Insight into Daylight Photocatalysis of AgBr@Ag: Synergistic Effect between Semiconductor Photocatalysis and Plasmonic Photocatalysis (pages 6360–6369)

      Jing Jiang , Hao Li and Prof. Dr. Lizhi Zhang

      Article first published online: 19 APR 2012 | DOI: 10.1002/chem.201102606

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      Indoor daylight active photocatalysts AgBr@Ag consisting of Ag nanoparticles and AgBr polyhedra were synthesized by a facile one-pot nonaqueous microwave route. Their enhanced daylight photocatalytic activity could be attributed to a synergistic effect between Ag plasmonic photocatalysis and conventional AgBr semiconductor photocatalysis (see figure).

    22. Radical Reactions

      The Reaction of Sulfenic Acids with Peroxyl Radicals: Insights into the Radical-Trapping Antioxidant Activity of Plant-Derived Thiosulfinates (pages 6370–6379)

      Dr. Riccardo Amorati, Philip T. Lynett, Dr. Luca Valgimigli and Prof. Dr. Derek A. Pratt

      Article first published online: 30 MAR 2012 | DOI: 10.1002/chem.201103459

      Thumbnail image of graphical abstract

      The first direct determination of sulfenic acid radical kinetics supports their involvement as redox-active intermediates in various processes in nature. Inhibited autoxidations and peroxyl radical clock experiments with (S)-benzyl phenylmethanethiosulfinate and a corresponding deuterium-labeled compound, provide unequivocal evidence for the intervention of sulfenic acids in the radical-trapping activity of plant-derived thiosulfinates (see scheme).

    23. Heterometallic Complexes

      Dual Catalysis with an IrIII–AuI Heterodimetallic Complex: Reduction of Nitroarenes by Transfer Hydrogenation using Primary Alcohols (pages 6380–6385)

      Sara Sabater, Jose A. Mata and Eduardo Peris

      Article first published online: 27 MAR 2012 | DOI: 10.1002/chem.201103657

      Thumbnail image of graphical abstract

      Better together! Reduction of nitrobenzene using benzyl alcohol in the presence of a gold/gold catalyst affords the hydroxylamine (see scheme). Under the same reaction conditions, an iridium/gold catalyst yields N-benzylideneaniline, the condensation product of aniline and benzaldehyde.

    24. Fluorescence

      Synthesis, Structure, Spectroscopic, and Electrochemical Properties of Highly Fluorescent Phosphorus(V)–meso-Triarylcorroles (pages 6386–6396)

      Avijit Ghosh and Prof. Mangalampalli Ravikanth

      Article first published online: 30 MAR 2012 | DOI: 10.1002/chem.201103226

      Thumbnail image of graphical abstract

      Brightly emissive: The highly fluorescent PV complexes of seven meso-triarylcorroles were synthesized and their properties were studied (see figure).

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      Preview: Chem. Eur. J. 21/2012 (page 6399)

      Article first published online: 3 MAY 2012 | DOI: 10.1002/chem.201290082

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