ChemPhysChem

Cover image for Vol. 7 Issue 10

October 13, 2006

Volume 7, Issue 10

Pages 2029–2226

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireviews
    5. Communications
    6. Articles
    7. Preview
    1. Cover Picture: Intercalated Smectic A Phases in Banana-Shaped Liquid Crystals with Carbonate End Groups (ChemPhysChem 10/2006) (page 2029)

      Katalin Fodor-Csorba, Antal Jákli, Anikó Vajda, S. Krishna Prasad, Doddamane S. Shankar Rao, Ronald Y. Dong, Jiadi Xu and Giancarlo Galli

      Version of Record online: 2 OCT 2006 | DOI: 10.1002/cphc.200690032

      The cover picture shows bent-core liquid crystals forming an intercalated smectic A (SmAint) phase, which has high birefringence and is switchable due to electric field-induced biaxiality. The left half of the picture shows the texture and the corresponding schematic arrangement of the molecules in the ground state. The right half shows the texture and the corresponding molecular arrangement in the electrode area, where the molecular planes turn parallel to the electric field. Find out more in the Article by Fodor-Csorba et al. on page 2184.

  2. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireviews
    5. Communications
    6. Articles
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  3. Minireviews

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireviews
    5. Communications
    6. Articles
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    1. Interplay between O2 and SnO2: Oxygen Ionosorption and Spectroscopic Evidence for Adsorbed Oxygen (pages 2041–2052)

      Alexander Gurlo

      Version of Record online: 6 SEP 2006 | DOI: 10.1002/cphc.200600292

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      The superoxide dead end: The mechanism of oxygen interaction with semiconducting metal oxides lacks spectroscopic evidence for “ionosorbed” oxygen species [superoxide (O2), peroxide ions (O22−) and charged atomic oxygen (O)] under real working conditions of sensors. The superoxide ion does not transform into charged atomic oxygen at the surface and represents a “dead-end” form of low-temperature oxygen adsorption on reduced surfaces (see figure).

    2. Electronic Phase Separation in Correlated Oxides: The Phenomenon, Its Present Status and Future Prospects (pages 2053–2059)

      Vijay B. Shenoy, D. D. Sarma and C. N. R. Rao

      Version of Record online: 24 AUG 2006 | DOI: 10.1002/cphc.200600188

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      Probing phase puddles: The fascinating phenomenon of electronic phase separation in oxides is examined. This Minireview, which focuses particularly on manganites, discusses the signatures of electronic inhomogeneities (see picture) and presents some of the theoretical approaches that have been proposed to explain it. A brief discussion on possible future research directions is also given.

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireviews
    5. Communications
    6. Articles
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    1. On the Influence of the Local Environment on the CO Stretching Frequencies in Native Myoglobin: Assignment of the B-States in MbCO (pages 2061–2063)

      Markus Meuwly

      Version of Record online: 6 SEP 2006 | DOI: 10.1002/cphc.200600304

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      Frequency shifts: The influence of the local electrostatic environment on the ground vibrational level of photodissociated CO in native myoglobin is investigated by performing QM/MM calculations at the DFT level. The distribution of CO frequencies in the Fe[BOND]CO conformation occurs at higher wavenumbers than in the Fe[BOND]OC conformation (see figure).

    2. Origin of the Large Spin–Orbit Effect in the Vibrational Frequencies of Haloalkane Cations (pages 2064–2066)

      Mina Lee and Myung Soo Kim

      Version of Record online: 20 SEP 2006 | DOI: 10.1002/cphc.200600449

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      In a spin: The vibrational frequencies of open-shell molecular cations are dramatically affected by spin–orbit coupling. The authors show that hyperconjugative inter-halogen interaction plays a vital role and that the effect can be magnified when intermediate, rather than very strong or very weak, interactions are present.

    3. Evaporation of Sessile Water Droplets on Superhydrophobic Natural Lotus and Biomimetic Polymer Surfaces (pages 2067–2070)

      Xiaoyan Zhang, Shuaixia Tan, Ning Zhao, Xinglin Guo, Xiaoli Zhang, Yongjun Zhang and Jian Xu

      Version of Record online: 29 AUG 2006 | DOI: 10.1002/cphc.200600229

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      An exceptional evaporation pattern is observed on special micro–nano hierarchically structured superhydrophobic natural lotus and biomimetic polymer surfaces. The evaporation process is simulated by the ellipsoidal cap-geometry model, which fits the experimental data well. The picture shows the contact angle (CA) and the height (h) of a water droplet on a natural lotus surface versus the evaporation time based on the ellipsoidal (+) and spherical (×) models.

    4. Lipid Tubes with a Temperature-Tunable Diameter (pages 2071–2073)

      Jean-Paul Douliez, Bruno Pontoire and Cédric Gaillard

      Version of Record online: 6 SEP 2006 | DOI: 10.1002/cphc.200600264

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      Controlled release: Lipid tubes (composed of hydroxy fatty acids) exhibit a change in their diameter upon increasing temperature (see figure). The temperature at which this change occurs is tuned by modulating the lipid composition. These findings show that hydroxy fatty acids have fascinating self-assembly properties, with potential applications in controlled-release systems.

    5. Selective Solvation of Cyclodextrins by Small Molecules: A NOE Study (pages 2074–2076)

      Andrés Guerrero-Martínez, Stefan Berger and Gloria Tardajos

      Version of Record online: 29 AUG 2006 | DOI: 10.1002/cphc.200600314

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      A study of the solvation state of α- cyclodextrin (α-CD) in water and in a water–trifluoroethanol (TFE) mixture is carried out by measuring homo- and heteronuclear intermolecular NOE (nuclear Overhauser effect) enhancements. The results give evidence of the site specificity of CD regions in solute–solvent interactions as a consequence of an internal complexation, which can be explained by the different hydrophobicity patterns of the CDs (see figure).

    6. Aromatic Ketones as Photocatalysts: Combined Action as Triplet Photosensitiser and Ground State Electron Acceptor (pages 2077–2080)

      Julia Pérez-Prieto, Raquel E. Galian and Maria C. Morant-Miñana

      Version of Record online: 22 SEP 2006 | DOI: 10.1002/cphc.200600328

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      Dual function: The potential of aromatic ketones as photocatalysts, acting as triplet–triplet photosensitisers and subsequently, as ground state electron acceptors is shown for the photosensitised oxidative decarboxylation of naproxen (see figure).

    7. Improved Model for Inhibition of Pathological Mineralization Based on Citrate–Calcium Oxalate Monohydrate Interaction (pages 2081–2084)

      Matthew L. Weaver, S. Roger Qiu, John R. Hoyer, William H. Casey, George H. Nancollas and James J. De Yoreo

      Version of Record online: 29 AUG 2006 | DOI: 10.1002/cphc.200600371

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      Molecular-scale kinetics of calcium oxalate growth inhibition in the presence of citrate has been investigated using in situ AFM (see lower microstructure image). Theoretical analysis of the data shows that the classic Cabrera–Vermilyea model of step pinning correctly predicts calcium oxalate monohydrate step kinetics when a Langmuir model of impurity adsorption dynamics and kink-site blocking is included.

    8. Circular Dichroism Laser Mass Spectrometry: Differentiation of 3-Methylcyclopentanone Enantiomers (pages 2085–2087)

      Ulrich Boesl von Grafenstein and Alexander Bornschlegl

      Version of Record online: 29 AUG 2006 | DOI: 10.1002/cphc.200600376

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      Rotational sense does matter! Left and right circularly polarised laser light can be used to achieve different ionisation yields when applying multiphoton ionisation to chiral ketones (see picture). So a new type of enantioselective laser mass spectrometry becomes possible which also gives information on the involved electronic transitions.

  5. Articles

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireviews
    5. Communications
    6. Articles
    7. Preview
    1. Excited-State Properties and Environmental Effects for Protonated Schiff Bases: A Theoretical Study (pages 2089–2096)

      Adélia J. A. Aquino, Mario Barbatti and Hans Lischka

      Version of Record online: 29 AUG 2006 | DOI: 10.1002/cphc.200600199

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      Retinal models: A protonated Schiff base (PSB) interacting with a solvated formate molecule (FM4W) represents a model for the retinal chromophore (see figure). Proton transfer (PT) from PSB to FM4W is investigated in the electronic ground state and in the ππ* state of the PSB. The calculations show a significant increase in feasibility of the PT in the excited state, which could compete with the traditional cistrans isomerization pathway.

    2. The Solution Structure of Stilbenoid Dendrimers: A Small-Angle Scattering Study (pages 2097–2104)

      Sabine Rosenfeldt, Elena Karpuk, Matthias Lehmann, Herbert Meier, Peter Lindner, Ludger Harnau and Matthias Ballauff

      Version of Record online: 15 SEP 2006 | DOI: 10.1002/cphc.200600231

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      A first analysis of stilbenoid dendrimers in solution demonstrates that these dendrimers (see picture) exhibit a flat structure. Moreover, comparison of small-angle X-ray scattering and small-angle neutron scattering data shows that the alkoxy chains attached to the periphery of the dendritic core are not fully localized in the plane of the core. These observations are an important contribution to the field of dendrimers and their analysis in solution.

    3. The N3+ Reactivity in Ionized Gases Containing Sulfur, Nitrogen, and Carbon Oxides (pages 2105–2114)

      Giulia de Petris, Antonella Cartoni, Giancarlo Angelini, Ornella Ursini, Andrea Bottoni and Matteo Calvaresi

      Version of Record online: 21 SEP 2006 | DOI: 10.1002/cphc.200600245

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      “N3+-specific” reactions are unraveled in ionized mixtures containing N2 and inorganic oxides. The N+ transfer to SO2 and N2O prompts activation of the S[BOND]O and N[BOND]N bonds (A), which gives a dual pathway to NO+ ions and neutral oxides. Stable NCO2+ and NCO+ products are formed by N+ transfer to CO2 and CO (B).

    4. Polymer Matrix Effects on the Nonlinear Optical Response of Incorporated Chromophore: New Analytical Models (pages 2115–2125)

      Marina Yu. Balakina

      Version of Record online: 13 SEP 2006 | DOI: 10.1002/cphc.200600263

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      Cavity ansatz: Four exactly solvable electrostatic models, two singular and two nonsingular, are suggested for the description of a local electric field affecting the nonlinear optical (NLO) chromophore in a polymer electret. The structure of the cavity inherits the symmetry of the generalized permittivity tensor of surrounding polymer material (see picture).

    5. Properties of Hydration Shells of Protein Molecules at their Pressure- and Temperature-Induced Native-Denatured Transition (pages 2126–2133)

      Irena Danielewicz-Ferchmin, Ewa M. Banachowicz and A. Ryszard Ferchmin

      Version of Record online: 6 SEP 2006 | DOI: 10.1002/cphc.200600289

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      Stay hydrated: A single value σD of the surface charge density σ at the surface of protein molecules is defined by two different points [see figure (T1, P1) (blue) and (T2, P2) (red)] taken from the native-denatured transition line of a protein. This occurs at the crossing of two (P+Π) vs σ isotherms of water at temperatures T1 (blue line) and T2 (red line) where P is the external pressure and Π is the electrostriction pressure.

    6. The Cell-Penetrating Peptide TAT(48-60) Induces a Non-Lamellar Phase in DMPC Membranes (pages 2134–2142)

      Sergii Afonin, Alexander Frey, Sybille Bayerl, Dahlia Fischer, Parvesh Wadhwani, Sevil Weinkauf and Anne S. Ulrich

      Version of Record online: 20 SEP 2006 | DOI: 10.1002/cphc.200600306

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      Rodlike lipid micelles, presumably of the inverted type, are induced in uncharged phosphatidylcholine bilayer membranes by the arginine-rich cell-penetrating peptide (CPP) TAT(48-60), as shown in the schematic picture. The formation of non-lamellar lipid structures is demonstrated by observation of an isotropic 31P NMR signal and electron microscopy, and they may be intermediates in the translocation of CPPs across eukaryotic membranes.

    7. Stability and Electrostatics of Mercaptoundecanoic Acid-Capped Gold Nanoparticles with Varying Counterion Size (pages 2143–2149)

      Timo Laaksonen, Päivi Ahonen, Christoffer Johans and Kyösti Kontturi

      Version of Record online: 13 SEP 2006 | DOI: 10.1002/cphc.200600307

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      Increased stability with larger counterions: The solubility of charged nanoparticles is critically dependent on pH and counterion size. Enhanced stability is observed for mercaptoundecanoic acid capped gold particles in the presence of bulky quaternary ammonium hydroxides as opposed to sodium hydroxide. The authors show that this is linked to a strongly bound ion layer at the particle surface.

    8. Computationally-Assisted Approach to the Vibrational Spectra of Molecular Crystals: Study of Hydrogen-Bonding and Pseudo-Polymorphism (pages 2150–2161)

      Mariela M. Nolasco, Ana M. Amado and Paulo J. A. Ribeiro-Claro

      Version of Record online: 19 SEP 2006 | DOI: 10.1002/cphc.200600308

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      “Pairs in molecular materials” (PiMM) is a new computationally-assisted methodology which provides a reliable and complete vibrational assignment of interacting molecules in the crystalline form. The authors simulate and estimate the effects of intermolecular interactions in three pseudo-polymorphic forms of methyl-xanthine derivatives (one of which is caffeine, see figure).

    9. Voltammetric Sizing of a Sphere (pages 2162–2167)

      Nicole Fietkau, François G. Chevallier, Li Jiang, Timothy G. J. Jones and Richard G. Compton

      Version of Record online: 20 SEP 2006 | DOI: 10.1002/cphc.200600310

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      The size of a glass sphere positioned in the center of a microdisk electrode (see figure) is determined by using a simple electrochemical procedure. The cyclic voltammetric response is recorded over a wide range of scan rates and the size of the sphere is then determined by comparison of the experimental voltammogram with simulations for each individual scan rate.

    10. Cooperative Interactions in Supramolecular Aggregates: Linear and Nonlinear Responses in Calix[4]arenes (pages 2168–2174)

      Ayan Datta, Francesca Terenziani and Anna Painelli

      Version of Record online: 19 SEP 2006 | DOI: 10.1002/cphc.200600336

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      Physics of polar-polarizable chromophores: Theoretical modeling and computation of the linear and nonlinear polarizabilities of calix[4]arene decorated with dipolar chromophores (see picture) reveal that interchromophore electrostatic interactions decrease/increase the linear and nonlinear responses with respect to the additive results (orientated-gas model) for neutral/zwitterionic functionalizing chromophores.

    11. Diastereodifferentiation of Novel Naphthalene Dyads by Fluorescence Quenching and Excimer Formation (pages 2175–2183)

      Sergio Abad, Ignacio Vayá, M. Consuelo Jiménez, Uwe Pischel and Miguel A. Miranda

      Version of Record online: 20 SEP 2006 | DOI: 10.1002/cphc.200600337

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      Diastereomeric differentiation of monomer fluorescence quenching and excimer formation in naphthalene chromophore containing dyads is observed. The results are rationalized by invoking two main excited state deactivation pathways, that is, photoinduced electron transfer and excimer formation. The latter requires ground-state pre-organization of the two chromophores as verified by the correlation of 1H NMR and fluorescence data.

    12. Intercalated Smectic A Phases in Banana-Shaped Liquid Crystals with Carbonate End Groups (pages 2184–2188)

      Katalin Fodor-Csorba, Antal Jákli, Anikó Vajda, S. Krishna Prasad, Doddamane S. Shankar Rao, Ronald Y. Dong, Jiadi Xu and Giancarlo Galli

      Version of Record online: 14 SEP 2006 | DOI: 10.1002/cphc.200600377

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      Bent-core liquid crystals: These new ester-type symmetrical bent-core liquid crystals with carbonate end groups have nematic and SmAint mesophases, which are quite different from those of the well-known rod-like compounds. In the SmAint phase these new compounds show large electric field-induced biaxiality which can be induced in less than 1 ms. The picture shows the texture of the SmAint phase, where an electric field is applied to the upper electrode area.

    13. Can Raman Optical Activity Separate Axial from Local Chirality? A Theoretical Study of Helical Deca-Alanine (pages 2189–2196)

      Carmen Herrmann, Kenneth Ruud and Markus Reiher

      Version of Record online: 29 AUG 2006 | DOI: 10.1002/cphc.200600391

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      Common patterns: Motivated by the destinction of protein secondary structure motifs by Raman optical activity (ROA) spectroscopy, it is demonstrated, using density functional theory, that ROA spectroscopy can filter out identical axial chirality in structures with different local chirality. A modified scheme for the interpretation of calculated ROA spectra of large molecules is suggested.

    14. Asymmetry Induction by Cooperative Intermolecular Hydrogen Bonds in Surface-Anchored Layers of Achiral Molecules (pages 2197–2204)

      Alexandre Dmitriev, Hannes Spillmann, Sebastian Stepanow, Thomas Strunskus, Christof Wöll, Ari P. Seitsonen, Magali Lingenfelder, Nian Lin, Johannes V. Barth and Klaus Kern

      Version of Record online: 6 SEP 2006 | DOI: 10.1002/cphc.200600110

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      Mesoscale supramolecular chirality induction is achieved by self-assembly of achiral trimellitic acid molecules on a Cu(100) surface. The appreciable substrate–adsorbate interactions induce changes in the surface morphology, which result in the formation of homochiral R and S terrace patterns (see figure).

    15. Hydrocarbon Bond Dissociation Enthalpies: From Substituted Aromatics to Large Polyaromatics (pages 2205–2214)

      Veronique Van Speybroeck, Guy B. Marin and Michel Waroquier

      Version of Record online: 21 SEP 2006 | DOI: 10.1002/cphc.200600161

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      Radical stability: Bond dissociation enthalpies (BDEs) of hydrocarbon species are calculated using density functional theory methods. The studied molecules range from small species which have been investigated experimentally to large polyaromatics. Differences in local structure result in sites (P, B, BP and DBP) with different reactivity (see figure), and BDE deviations up to 35 kJ mol−1 for crowded condensed aromatics are obtained.

    16. Optical Properties of Lanthanide-Doped Lamellar Nanohybrids (pages 2215–2222)

      Rute A. Sá Ferreira, Mohamed Karmaoui, Sónia S. Nobre, Luís D. Carlos and Nicola Pinna

      Version of Record online: 29 AUG 2006 | DOI: 10.1002/cphc.200600317

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      Worthy competitors: The optical properties of lanthanide-doped lamellar nanohybrids synthesized by the “benzyl alcohol route” is presented. The radiance values are comparable and in some cases even larger than those of standard phosphors, proving that these nanohybrids can compete, from an emission efficiency point of view, with commercial phosphors (see figure).

  6. Preview

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Minireviews
    5. Communications
    6. Articles
    7. Preview
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      Preview: ChemPhysChem 10/2006 (page 2226)

      Version of Record online: 2 OCT 2006 | DOI: 10.1002/cphc.200690034

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