ChemPhysChem

Cover image for Vol. 6 Issue 2

February 11, 2005

Volume 6, Issue 2

Pages 197–378

    1. Cover Picture: Femtosecond Time-Resolved Geometry Relaxation and Ultrafast Intramolecular Energy Redistribution in Ag2Au (ChemPhysChem 2/2005) (page 197)

      Thorsten M. Bernhardt, Jan Hagen, Liana D. Socaciu, Roland Mitrić, Andreas Heidenreich, Jérôme Le Roux, Denisia Popolan, Mihai Vaida, Ludger Wöste, Vlasta Bonačić-Koutecký and Joshua Jortner

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200490063

      The cover picture shows an artist's view of the dynamical evolution of the bimetallic cluster Ag2Au in the neutral electronic ground state after photodetachment of the anion. Femtosecond negative ion–to-neutral–to-positive ion (NeNePo) pump-probe spectroscopy (open circles) at two different probe wavelengths (blue: 350 nm; red: 406 nm) and theoretical simulations (solid lines) are employed to monitor the dynamical processes of geometry relaxation followed by intramolecular vibrational energy redistribution (IVR) to the probe-wavelength dependent NeNePo signals. In their Article on page 243 Bernhardt et al. provide detailed insight into the ultrafast nuclear dynamics in this model-type cluster system.

    2. Nanoparticles and Nanocapsules Created Using the Ouzo Effect: Spontaneous Emulsification as an Alternative to Ultrasonic and High-Shear Devices (pages 209–216)

      François Ganachaud and Joseph L. Katz

      Version of Record online: 13 JAN 2005 | DOI: 10.1002/cphc.200400527

      Thumbnail image of graphical abstract

      New interpretations: The preparation of polymer aqueous dispersions by means of the spontaneous emulsification of polymers or monomers is reviewed. The results are correlated with recent observations on the process governing spontaneous emulsification—otherwise named the Ouzo effect—which entails the formation of silicone microgels, polymer particles, and air- or oil-filled capsules (see figure).

    3. Design of Molecular Photonic Wires Based on Multistep Electronic Excitation Transfer (pages 217–222)

      Philip Tinnefeld, Mike Heilemann and Markus Sauer

      Version of Record online: 20 JAN 2005 | DOI: 10.1002/cphc.200400513

      Thumbnail image of graphical abstract

      Photonic nanowires: The large energy-transfer efficiency achieved by natural antenna complexes stimulated the synthesis of artificial multichromophoric systems. The authors discuss the design and synthesis of photonic wires based on coherent and incoherent electronic excitation transfer (see figure) and demonstrate the advantages of single-molecule fluorescence spectroscopy for the study of such complex systems.

    4. “Hot Spot” Hydrocarbon Oxidation Catalysed by Doped Perovskites—Towards Cleaner Diesel Power (pages 223–225)

      Jurriaan Beckers and Gadi Rothenberg

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400421

      Thumbnail image of graphical abstract

      Spot the difference: Oxidation of propane/CO mixtures is efficiently catalysed by mixed perovskite oxides heated directly using microwave irradiation (see figure). A set of twelve catalysts is screened for activity, selectivity and stability towards SO2 poisoning. LaSrMn shows good activity, selectivity and heating capabilities, while LaSrCr is found to be superbly resistant to SO2 poisoning.

    5. Templating Effect of Lipid Membranes on Alzheimer's Amyloid Beta Peptide (pages 226–229)

      Canay Ege, Jaroslaw Majewski, Guohui Wu, Kristian Kjaer and Ka Yee C. Lee

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400468

      Thumbnail image of graphical abstract

      Electrostatic influence on peptide association: The first X-ray reflectivity and grazing-incidence X-ray diffraction study on amyloid beta peptide and lipid monolayers provides insight into the differences in the interaction of the peptide with cationic and anionic monolayers (see picture). A unique templating effect is observed in the latter case.

    6. Infrared Spectrum of the Au–C60 Complex (pages 229–232)

      Jonathan T. Lyon and Lester Andrews

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400467

      Thumbnail image of graphical abstract

      Noble metal–fullerene complexes: Laser-ablated gold atoms react with C60 vapor in excess argon to form the exohedral Au[BOND]C60 complex (see figure), which is identified by infrared and Raman fundamentals of C60 itself. Strong infrared absorptions result from three T1u modes, one Ag mode, and one Hg mode of C60, while weaker absorptions derive from other Ag and five Hg modes of C60.

    7. Persistent Methylbenzenium Ions in Protonated Zeolites: The Required Proton Affinity of the Guest Hydrocarbon (pages 232–235)

      Morten Bjørgen, Francesca Bonino, Bjørnar Arstad, Stein Kolboe, Karl-Petter Lillerud, Adriano Zecchina and Silvia Bordiga

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400422

      Thumbnail image of graphical abstract

      Protonated zeolites: Tetramethylbenzene (durene) forms a long-lived mechanistically relevant carbenium ion within the micropores of zeolite H-beta. Fourier transform infrared spectroscopy proved the existence of the cation by an absorption at 1604 cm−1. Also an electronic transition at 26 500 cm−1, inherently linked to the tetramethylbenzenium cation, was observed. The cation was remarkably stable in the cavities of the zeolite, even at 400 K.

    8. Morphology of Frozen Rare-Gas Layers (pages 235–238)

      Sergej A. Nepijko, Irene Rabin and Wilfried Schulze

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400420

      Thumbnail image of graphical abstract

      Solid gas surfaces: The porosity of frozen rare-gas layers (Ar, Kr, and Xe) was visualized by a replica technique. Ag films were produced by condensation of Ag atoms onto freshly prepared solid (frozen) rare-gas layers. The resulting replicas of the rare-gas surfaces were investigated by atomic force (see two- and three-dimensional pictures) and scanning electron microscopy.

    9. Reversible Force Generation in a Temperature-Responsive Nanocomposite Hydrogel Consisting of Poly(N-isopropylacrylamide) and Clay (pages 238–241)

      Kazutoshi Haraguchi, Shinichi Taniguchi and Toru Takehisa

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400398

      Thumbnail image of graphical abstract

      Generated force profiles: The authors report the first observation of a retractive mechanical force as a result of a coil–globular transition of poly(N-isopropylacrylamide) chains. Using temperature-sensitive nanocomposite hydrogels, they observed the reversible generation of retractive tensile forces in samples constrained to a constant length in an aqueous environment, in response to alternating the temperature across the lower critical solution temperature.

    10. Femtosecond Time-Resolved Geometry Relaxation and Ultrafast Intramolecular Energy Redistribution in Ag2Au (pages 243–253)

      Thorsten M. Bernhardt, Jan Hagen, Liana D. Socaciu, Roland Mitrić, Andreas Heidenreich, Jérôme Le Roux, Denisia Popolan, Mihai Vaida, Ludger Wöste, Vlasta Bonačić-Koutecký and Joshua Jortner

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400454

      Thumbnail image of graphical abstract

      Three's a crowd: A three-atom molecule or cluster is the simplest system in which intramolecular vibrational energy redistribution (IVR) can occur. In the case of the trimer Ag2Au, femtosecond time-resolved spectroscopy in combination with theoretical simulations (see picture) provide a detailed insight into the ultrafast nuclear dynamics associated with the fundamental process of IVR on the neutral electronic ground-state potential energy surface.

    11. A DFT Study of the Adsorption and Dissociation of CO on Fe(100): Influence of Surface Coverage on the Nature of Accessible Adsorption States (pages 254–260)

      Tracy C. Bromfield, Daniel Curulla Ferré and J. W. Niemantsverdriet

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400452

      Thumbnail image of graphical abstract

      Adsorption of CO on Fe(100) was investigated using density functional theory. Adsorption energies, structures, and vibrational frequencies of CO on Fe(100) at three surface coverages reveal that molecular adsorption is stabilized with respect to dissociation when the coverage is increased from 0.25 to 0.5 monolayers (see graphic).

    12. Geometry Optimization and Conformational Analysis of (C60)N Clusters Using a Dynamic Lattice-Searching Method (pages 261–266)

      Longjiu Cheng, Wensheng Cai and Xueguang Shao

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400425

      Thumbnail image of graphical abstract

      Hit numbers of funnel bottoms on the potential energy surface of (C60)N clusters with various packing sequences are shown in the figure (T=tetrahedral, D(+)=decahedral plus an antilayer) together with the cluster size. Dynamic lattice searching is unbiased and randomly initialized, so that configurations with a larger hit number will be more favored. Therefore, the dominant configurations stand out for a given cluster size.

    13. One- and Two-Photon Photochemistry and Photophysics of Poly(arylenevinylene)s Containing a Biphenyl Moiety (pages 267–276)

      Veronika Strehmel, Ananda M. Sarker, Paul M. Lahti, Frank E. Karasz, Matthias Heydenreich, Hendrik Wetzel, Sophie Haebel and Bernd Strehmel

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400407

      Thumbnail image of graphical abstract

      Two-photon absorption of conjugated oligomers: Two-photon (TP) excitation of poly[(2,5-alkyloxy-p-phenylenevinylene)alt-(biphenylenevinylene)] (see figure) results in a TP absorption cross-section of >200 GM (GM=Göppert–Mayer units) if R=O[BOND]Alkyl, whereas less TP absorptivity is observed when R=H. The Strickler–Berg relation was applied to evaluate the effective conjugation length as a quantity that reliably contributes to the photonic properties determined.

    14. Molecular Adsorption-Mediated Control over the Electrical Characteristics of Polycrystalline CdTe/CdS Solar Cells (pages 277–285)

      Iris Visoly-Fisher, Amit Sitt, Melina Wahab and David Cahen

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400392

      Thumbnail image of graphical abstract

      Chemical modification of semiconductors can change their electronic surface energetics. In polycrystalline semiconductors with large surface areas, this can affect the bulk electronic behavior of the materials and devices made therefrom. We show how chemisorption of organic molecules on CdTe grain boundaries and surfaces (see schematic picture) of polycrystalline thin-film p-CdTe/n-CdS solar cells systematically affects their photovoltaic properties.

    15. The Kinetics of Z/E Isomerization of Methyl Oleate Catalyzed by Photogenerated Thiyl Radicals (pages 286–291)

      Chryssostomos Chatgilialoglu, Abdelouahid Samadi, Maurizio Guerra and Hanns Fischer

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400388

      Thumbnail image of graphical abstract

      Radical analysis: The rate constants for thiyl radical (HOCH2CH2S.) addition to methyl oleate and methyl elaidate—and for the reversible reactions—were obtained at room temperature under photolytic conditions. Calculations on 2-butene (see figure) indicated a lower activation barrier for the formation of the E transition state from the equilibrium radical adduct structure.

    16. Probing the N(5)[BOND]H Bond of the Isoalloxazine Moiety of Flavin Radicals by X- and W-Band Pulsed Electron–Nuclear Double Resonance (pages 292–299)

      Stefan Weber, Christopher W. M. Kay, Adelbert Bacher, Gerald Richter and Robert Bittl

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400377

      Thumbnail image of graphical abstract

      The geometry of hydrogen bonds in flavoproteins can be extracted from pulsed electron–nuclear double resonance (ENDOR) spectroscopy. Small differences between the proton and the deuteron hyperfine couplings allow to resolve subtle bond-length differences between N[BOND]D and N[BOND]H bonds (see figure).

    17. Phase Separation of LaI3 inside Single-Walled Carbon Nanotubes (pages 300–305)

      Steffi Friedrichs, Uwe Falke and Malcolm L. H. Green

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400361

      Thumbnail image of graphical abstract

      Confinement of LaI3 within the inner hollow cavity of a quasimetallic (18,3) single-walled carbon nanotube (SWNT) yielded LaI2 in an unprecedented structure (see picture), while adjacent SWNTs were found to be filled with quasicrystalline I2.

    18. On the Low-Lying Excited States of sym-Triazine-Based Herbicides (pages 306–314)

      Josep M. Oliva, M. Emilia D. G. Azenha, Hugh D. Burrows, Rita Coimbra, J. Serxio Seixas de Melo, Moisés Canle L., M. Isabel Fernández, J. Arturo Santaballa and Luis Serrano-Andrés

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400349

      Thumbnail image of graphical abstract

      The ubiquitous herbicides atrazine (X=Cl, R1=NHEt, R2=NHiPr) and ametryn (X=SCH3, R1=NHEt, R2=NHiPr), as well as the parent 1,3,5-triazine (1; X=R1=R2=H), were subjected to a joint computational and luminescence study of their low-lying excited states. The results of the CASPT2 calculations are in good agreement with the experimental results obtained from luminescence studies. A schematic Jablonski diagram for atrazine is shown in the picture.

    19. You have free access to this content
      Determining the Geometry of Hydrogen Bonds in Solids with Picometer Accuracy by Quantum-Chemical Calculations and NMR Spectroscopy (pages 315–327)

      Martin Schulz-Dobrick, Thorsten Metzroth, Hans Wolfgang Spiess, Jürgen Gauss and Ingo Schnell

      Version of Record online: 20 JAN 2005 | DOI: 10.1002/cphc.200400338

      Thumbnail image of graphical abstract

      A perfect pair: Solid-state NMR spectroscopy and quantum-chemical calculations ideally complement each other and are a powerful approach for reliable, high-precision structure determination. The position of hydrogen atoms in N[BOND]H⋅⋅⋅N hydrogen bonds and the structure of multiple hydrogen bonds can be determined with picometer accuracy by combining quantum-chemical computations and solid-state magic-angle spinning NMR experiments.

    20. Selective Fluorescence Recovery after Bleaching of Single E2GFP Proteins Induced by Two-Photon Excitation (pages 328–335)

      G. Chirico, A. Diaspro, F. Cannone, M. Collini, S. Bologna, V. Pellegrini and F. Beltram

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400318

      Thumbnail image of graphical abstract

      Permanently blinking proteins: Fluorescence recovery of the green fluorescent protein (GFP) mutant E2GFP can be obtained with high efficiency by laser irradiation in the near infrared, at 720 nm (see scheme of the electronic level structure). This GFP mutant seems promising as an “almost permanent” chromophore for two-photon excitation microscopy or for applications in single-molecule memory arrays.

    21. Interactions between Brushlike Polyacrylic Acid Side Chains on a Polyacrylate Backbone in Dioxane–Water (pages 336–343)

      Fengjun Hua, Rio Kita, Gerhard Wegner and Wolfgang Meyer

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400308

      Thumbnail image of graphical abstract

      Equilibrium of cluster formation: Densely grafted polyacrylic acids (d-PAA), with overcrowded PAA side chains on the polyacrylate main chains, were synthesized and characterized. In dioxane, the d-PAAs exhibit inter- and intramolecular hydrogen bonding between the carboxylic groups of the PAA side chains. Intermolecular hydrogen bonding produces aggregates (see picture). The clusters were found to shrink as the water concentration decreased.

    22. A Theoretical Analysis of the Coordination Modes of CuII with Penicillins: Activation of the β-Lactam C[BOND]N Bond (pages 344–351)

      Pablo Campomanes, M. Isabel Menéndez, Ramón López and Tomás L. Sordo

      Version of Record online: 20 JAN 2005 | DOI: 10.1002/cphc.200400280

      Thumbnail image of graphical abstract

      Degradation of β-lactam antibiotics in the presence of aqueous CuII could involve complexes in which the β-lactam C[BOND]N bond is activated by ligation of the metal ion, according to a theoretical study on complexes of CuII(H2O)2 and the penicillin model 6-acetylamino-3α-carboxypenam. The complex shown in the picture has a C[BOND]N bond length of 1.487 Å (uncoordinated penam: 1.379 Å), similar to those found in some tetrahedral intermediates located for the hydrolysis of 2-azetidinones.

    23. Graphite Powder and Multiwalled Carbon Nanotubes Chemically Modified with 4-Nitrobenzylamine (pages 352–362)

      Gregory G. Wildgoose, Shelley J. Wilkins, Gareth R. Williams, Robert R. France, David L. Carnahan, Li Jiang, Timothy G. J. Jones and Richard G. Compton

      Version of Record online: 13 JAN 2005 | DOI: 10.1002/cphc.200400403

      Thumbnail image of graphical abstract

      Derivatisation of carbon surfaces with 4-nitrobenzylamine (4-NBA) was successfully achieved and investigated by several techniques. The authors propose the partial intercalation of 4-NBA into localised edge-plane defect sites along the carbon surface of both graphite powder and multiwalled carbon nanotubes (MWCNTs). The mechanism of the electrochemical reduction of 4-NBA-modified carbon-based electrodes in aqueous and nonaqueous media was also investigated (see figure).

    24. Absolute Rate Calculations: Atom and Proton Transfers in Hydrogen-Bonded Systems (pages 363–371)

      Mónica Barroso, Luis G. Arnaut and Sebastião J. Formosinho

      Version of Record online: 13 JAN 2005 | DOI: 10.1002/cphc.200400285

      Thumbnail image of graphical abstract

      Strong hydrogen bonds are incipient proton transfers, and weak hydrogen bonds may increase tunneling by two orders of magnitude at room temperature, as revealed by absolute rate calculations on hydrogen-bonded systems (see figure).

    25. Modern Problems in Classical Electrodynamics. By Charles A. Brau. (page 374)

      Gilbert Chang and George C. Schatz

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200400366

    26. You have free access to this content
      Preview: ChemPhysChem 2/2005 (page 378)

      Version of Record online: 4 FEB 2005 | DOI: 10.1002/cphc.200490065

SEARCH

SEARCH BY CITATION