ChemPhysChem

Cover image for Vol. 8 Issue 5

April 2, 2007

Volume 8, Issue 5

Pages 625–766

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireview
    5. Communications
    6. Articles
    7. Book Review
    8. Preview
    1. Cover Picture: Excited-State Relaxation of Protonated Adenine (ChemPhysChem 5/2007) (page 625)

      Dirk Nolting, Rainer Weinkauf, Ingolf V. Hertel and Thomas Schultz

      Version of Record online: 21 MAR 2007 | DOI: 10.1002/cphc.200790010

      The cover picture shows the potential energy scheme of protonated adenine. The adenine molecule in front is in the ground-state equilibrium geometry whereas the molecule in the back shows the nonplanar structure after absorption of an UV photon. In their Article on page 751 Nolting et al. investigate the excited state dynamics of protonated adenine by femtosecond pump–probe transient mass spectrometry in the gas phase.

  2. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireview
    5. Communications
    6. Articles
    7. Book Review
    8. Preview
  3. Minireview

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireview
    5. Communications
    6. Articles
    7. Book Review
    8. Preview
    1. Pivotal Steps Towards Quantification of Molecular Diffusion Coefficients by NMR (pages 635–642)

      Shanmin Zhang

      Version of Record online: 5 MAR 2007 | DOI: 10.1002/cphc.200600740

      Thumbnail image of graphical abstract

      Quantifying diffusion: Selective excitation of a central region of an NMR sample using an offset-independent adiabatic inversion pulse and a pulsed field gradient (see picture) allows for the quantitative determination of molecular diffusion coefficients. This basic concept can be applied to one- and multi-dimensional NMR experiments.

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireview
    5. Communications
    6. Articles
    7. Book Review
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    1. 133Cs Diffusion NMR Spectroscopy: A Tool for Probing Metal Cation–π Interactions in Water (pages 643–645)

      Diana Cuc, Daniel Canet, Jean-Pierre Morel, Nicole Morel-Desrosiers and Pierre Mutzenhardt

      Version of Record online: 15 FEB 2007 | DOI: 10.1002/cphc.200600772

      Thumbnail image of graphical abstract

      Association phenomena: 133Cs and 1H diffusion NMR experiments give evidence of a 1:1 inclusion complex between p-sulfonatocalix[4]arene and a cesium ion in water (see picture); the complex is stabilized by cation–π interactions.

    2. Self-Association Based on Interfacial Structured Water Leads to {Mo154}≈1165 Super Clusters: A Dielectric Study (pages 646–649)

      Alla Oleinikova, Hermann Weingärtner, Martin Chaplin, Ekkehard Diemann, Hartmut Bögge and Achim Müller

      Version of Record online: 5 MAR 2007 | DOI: 10.1002/cphc.200600602

      Thumbnail image of graphical abstract

      Surface water does the job: Molybdenum blue solutions contain unique nanosized wheel-shaped polyoxometalate-type clusters, while structured surface water on the clusters initiates the assembly, leading to the super cluster shown in the figure, which contains an internal “water pool”.

    3. Advantages of a Redefinition of Variable-Space in Direct-Space Structure Solution from Powder X-Ray Diffraction Data (pages 650–653)

      Zhongfu Zhou, Veronique Siegler, Eugene Y. Cheung, Scott Habershon, Kenneth D. M. Harris and Roy L. Johnston

      Version of Record online: 9 MAR 2007 | DOI: 10.1002/cphc.200600726

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      A successful new strategy to determine the crystal structure from powder diffraction data is based on the genetic algorithm technique for global optimization. Individual molecules are defined as a small number of independent fragments rather than complete molecules (see figure); this increases the success rate, particularly in the challenging case of structure solution of conformationally flexible molecules.

    4. Pitfalls in Interpreting Temperature Programmed Desorption Spectra of Alloys: The CO/CoPt Puzzle (pages 654–656)

      Daniela Fenske, Wai-Leung Yim, Stephanie Neuendorf, Dirk Hoogestraat, Denis Greshnykh, Holger Borchert, Thorsten Klüner and Katharina Al-Shamery

      Version of Record online: 9 MAR 2007 | DOI: 10.1002/cphc.200700004

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      CO adsorption: Strong shifts in temperature-programmed desorption spectra may occur for alloys with respect to pure compounds as is demonstrated for CO adsorption on a CoPt surface (see figure). A correct interpretation of the data is only possible when corroborated with DFT calculations and a further experimental method such as IR reflection absorption spectroscopy.

    5. Chemistry in Confined Geometries: Reactions at an Organic Surface (pages 657–660)

      Ketheeswari Rajalingam, Asif Bashir, Mihaela Badin, Felicitas Schröder, Ned Hardman, Thomas Strunskus, Roland A. Fischer and Christof Wöll

      Version of Record online: 5 MAR 2007 | DOI: 10.1002/cphc.200700044

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      Two-dimensional reactions: Modification of organothiol self-assembled monolayers (SAMs) adsorbed on solid surfaces opens new possibilities for applications of such systems. However, reactions at organic monolayers display vastly different kinetics than in solution and are shown to initiate at defects in the monolayer structure and proceed along a one-dimensional reaction front (see picture).

  5. Articles

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireview
    5. Communications
    6. Articles
    7. Book Review
    8. Preview
    1. Dynamics or Stochastic Conductance Switching of Phenylene–Ethynylene Oligomers? (pages 661–665)

      Ann-Sofie Hallbäck, Bene Poelsema and Harold J. W. Zandvliet

      Version of Record online: 22 FEB 2007 | DOI: 10.1002/cphc.200600744

      Thumbnail image of graphical abstract

      Spontaneous changes in the appearance of phenylene–ethynylene oligomers on the Au(111) surface occur by diffusion and exchange of molecules. The figure shows fluctuations of the number of molecules in the oligomer bundles at room temperature.

    2. Mesoporous Pt–SiO2 and Pt–SiO2–Ta2O5 Catalysts Prepared Using Pt Colloids as Templates (pages 666–678)

      Vasile I. Pârvulescu, Viorica Pârvulescu, Uwe Endruschat, Pascal Granger and Ryan Richards

      Version of Record online: 27 FEB 2007 | DOI: 10.1002/cphc.200600571

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      Sol-gel synthesis of silica and silica–tantalum oxide embedded platinum nanoparticles (see picture) is carried out using Pt colloids with different stabilizers as templates. The aim is to prepare mesoporous silica embedded Pt colloids combining the “precursor concept” with the model of preparation of catalysts using preformed spheres.

    3. Protein–Protein Interactions in Complex Cosolvent Solutions (pages 679–689)

      Nadeem Javid, Karsten Vogtt, Chris Krywka, Metin Tolan and Roland Winter

      Version of Record online: 28 FEB 2007 | DOI: 10.1002/cphc.200600631

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      Solution effects: Various kosmotropic and chaotropic cosolvents and salts are added to solutions of lysozyme, and static structure factors are determined experimentally (see picture). Statistical mechanical analysis allows for deconvolution of repulsive and attractive interactions, lending insight into protein–protein interactions on a molecular level.

    4. Anion and Cation Effects on Imidazolium Salt Melting Points: A Descriptor Modelling Study (pages 690–695)

      Ignacio López-Martin, Enrico Burello, Paul N. Davey, Kenneth R. Seddon and Gadi Rothenberg

      Version of Record online: 5 MAR 2007 | DOI: 10.1002/cphc.200600637

      Thumbnail image of graphical abstract

      Mix and match: A descriptor modelling approach in which anions and cations of ionic liquids are modelled separately, predicts the melting point of the ionic liquids (see schematic). The models include constitutional, topological and geometric descriptors as well as quantum mechanical ones. This approach gives access to n×m ionic liquids using only (n+m) calculations.

    5. Characterization of Pericyclic Reactions Using Multicenter Electron Delocalization Analysis (pages 696–702)

      Marcos Mandado, María J. González-Moa and Ricardo A. Mosquera

      Version of Record online: 5 MAR 2007 | DOI: 10.1002/cphc.200600682

      Thumbnail image of graphical abstract

      Concerted reaction? Multicenter delocalization analysis provides a measure of the aromaticity of molecules along reaction pathways (see picture). The study of several pericyclic and non-pericyclic reactions shows this tool to be a powerful one for studying concerted processes.

    6. A Kinetic Model for Nanocrystal Morphology Evolution (pages 703–711)

      Xiangxing Xu, Feng Liu, Kehan Yu, Wei Huang, Bo Peng and Wei Wei

      Version of Record online: 27 FEB 2007 | DOI: 10.1002/cphc.200600684

      Thumbnail image of graphical abstract

      Nanocrystal growth: A kinetic model is developed with the goal of understanding and predicting nanocrystal morphology evolution (see figure) in nonequilibrium growth conditions. The morphology evolution of CdSe nanocrystals is discussed as an example.

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      A Novel ATR-FTIR Approach for Characterisation and Identification of Ex Situ Immobilised Species (pages 712–722)

      Per Ola Andersson, Margaretha Lundquist, Lotta Tegler, Susanne Börjegren, Lars Baltzer and Lars Österlund

      Version of Record online: 22 FEB 2007 | DOI: 10.1002/cphc.200600691

      Thumbnail image of graphical abstract

      Characterisation of immobilisation steps: Nitriloacetic acid-coated copolymer of 10 μm thickness is ex situ immobilised and subsequently analysed by attenuated total reflection (ATR) Fourier infrared spectroscopy in a step-by-step process. Binding of polypeptides in aqueous solution to the Ni-NTA complex on the chip surface are well resolved as amide I and II bands, together with characteristic peptide–ligand peaks in the fingerprint region.

    8. Effect of Branching on Two-Photon Absorption in Triphenylbenzene Derivatives (pages 723–734)

      Francesca Terenziani, Céline Le Droumaguet, Claudine Katan, Olivier Mongin and Mireille Blanchard-Desce

      Version of Record online: 13 FEB 2007 | DOI: 10.1002/cphc.200600689

      Thumbnail image of graphical abstract

      Core control: The photophysical spectral properties of octupolar compounds with a triphenylbenzene core are compared with properties of corresponding dipolar branches. The figure shows the correlation between the solvatochromic fluorescence behavior and the two-photon absorption cross section, ascribed to the intramolecular charge-transfer character of the transitions.

    9. The Cyclohexasilanes Si6H11X and Si6Me11X with X=F, Cl, Br and I: A Quantum Chemical and Raman Spectroscopic Investigation of a Multiple Conformer Problem (pages 735–744)

      Margit Hölbling, Michaela Flock and Karl Hassler

      Version of Record online: 5 MAR 2007 | DOI: 10.1002/cphc.200600731

      Thumbnail image of graphical abstract

      Conformational flexibility: A theoretical investigation of conformer stabilities of Si6Me11X with X=F, Cl and Br (figure shows relative energies given in kJ mol−1 for Si6Me11Br) leads to seven minima. With the aid of vibrational Raman spectroscopy, the axial and equatorial chair conformers—and an averaged twist conformer—are observed in solution.

    10. Fourier Transform Raman and DFT Study of Three Annulated Oligothiophenes with Different Molecular Shapes (pages 745–750)

      Reyes Malavé Osuna, Rocio Ponce Ortiz, Mari Carmen Ruiz Delgado, Valentin G. Nenajdenko, Viktor V. Sumerin, Elizabeth S. Balenkova, Víctor Hernández and Juan Teodomiro López Navarrete

      Version of Record online: 28 FEB 2007 | DOI: 10.1002/cphc.200600734

      Thumbnail image of graphical abstract

      Thienoacenes for functional organic materials: The Raman spectra of three different thienoacenes show a great enhancement in the 1600–1300 cm−1 spectral region (see picture). Comparison of the computed vibrational eigenvectors with the topologies of the frontier molecular orbitals gives evidence of strong vibronic coupling.

    11. Excited-State Relaxation of Protonated Adenine (pages 751–755)

      Dirk Nolting, Rainer Weinkauf, Ingolf V. Hertel and Thomas Schultz

      Version of Record online: 15 MAR 2007 | DOI: 10.1002/cphc.200600727

      Thumbnail image of graphical abstract

      Photostability of adenine: Femtosecond pump–probe transient mass spectrometry was used to investigate the excited-state dynamics of protonated adenine in the gas phase. Fragmentation patterns are similar to those found for high-energy collision-induced dissociation mass spectra, and experimental evidence agrees well with predictions that a conical intersection to the ground state is accessed without a barrier.

    12. Photophysics of Eumelanin: Ab Initio Studies on the Electronic Spectroscopy and Photochemistry of 5,6-Dihydroxyindole (pages 756–762)

      Andrzej L. Sobolewski and Wolfgang Domcke

      Version of Record online: 6 FEB 2007 | DOI: 10.1002/cphc.200600768

      Thumbnail image of graphical abstract

      Sun tan: Ab initio calculations are used to investigate the photophysics of 5,6-dihydroxyindole (DHI), one of the elementary building blocks of a class of melanins, eumelanin. 6-Hydroxy-4-dihydro-indol-5-one (HHI) is formed via nonadiabatic hydrogen migration from DHI and represents a typical excited-state hydrogen-transfer (ESIHT) system.

  6. Book Review

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireview
    5. Communications
    6. Articles
    7. Book Review
    8. Preview
  7. Preview

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireview
    5. Communications
    6. Articles
    7. Book Review
    8. Preview
    1. You have free access to this content
      Preview: ChemPhysChem 6/2007 (page 766)

      Version of Record online: 21 MAR 2007 | DOI: 10.1002/cphc.200790012

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