Cover image for Vol. 5 Issue 8

August 20, 2004

Volume 5, Issue 8

Pages 1073–1254

    1. Cover Picture: Biomolecule-Functionalized Carbon Nanotubes: Applications in Nanobioelectronics (ChemPhysChem 8/2004) (page 1073)

      Eugenii Katz and Itamar Willner

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200490043

      The cover picture shows that biomolecule–carbon nanotube hybrids provide exciting new materials for bionanotechnology. In the Review on pp. 1084, E. Katz and I. Willner highlight recent advances in the field. The use of these systems for electronic biosensing, assembly of nanocircuitry, and the organization of nanoscale devices is discussed.

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    3. Biomolecule-Functionalized Carbon Nanotubes: Applications in Nanobioelectronics (pages 1084–1104)

      Eugenii Katz and Itamar Willner

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400193

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      Nanobioexposé: Combining carbon nanotubes with biomolecules (see picture) is a flourishing and fascinating field of research. This in-depth Review of nanobiotechnology summarizes the accomplishments that have been made to date, and addresses the exciting developments anticipated in the future.

    4. Non-Haloaluminate Room-Temperature Ionic Liquids in Electrochemistry—A Review (pages 1106–1120)

      Marisa C. Buzzeo, Russell G. Evans and Richard G. Compton

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200301017

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      Neoteric electrochemical solvents: Room-temperature ionic liquids (RTILs) are compounds comprised of a bulky organic cation and weakly coordinating inorganic anion. Their intrinsically high conductivity, wide potential windows, and thermal stability offer certain advantages over those traditionally employed. This Review details their electrochemical properties and highlights their use in solution-phase voltammetry (see graphic), gas detection, electrodeposition, electrosynthesis, and electrochemical devices.

    5. No Label Required: Protein Binding at Membrane Interfaces Visualized through Colloid Phase Transitions (pages 1121–1124)

      Claudia Steinem and Andreas Janshoff

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400092

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      Colloid science meets biology. A new method has been introduced to visualize the interaction of proteins (purple) with membrane-coated silica beads (surface shown in orange) by observing a phase transition from a condensed to a dispersed phase. Changes in the radial pair distribution function provide a sensitive means to quantify the interaction of proteins with membrane-confined receptors.

    6. Electrochemical Modulation of Remote Fluorescence Imaging at an Ordered Opto-electrochemical Nanoaperture Array (pages 1125–1132)

      Arnaud Chovin, Patrick Garrigue, Laurent Servant and Neso Sojic

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400015

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      Triggering light at the nanometer and micrometer scale: An ordered array which combines near-field optical methods and nanoelectrode properties is presented (see graphic). The ordered structure of nanometer light sources provides promising photonic or electro-optical devices for various future applications.

    7. Ethanol Decomposition: C[BOND]C Cleavage Selectivity on Rh(111) (pages 1133–1140)

      Erik Vesselli, Alessandro Baraldi, Giovanni Comelli, Silvano Lizzit and Renzo Rosei

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400043

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      Studying surface species: Efficient catalysts for ethanol reforming have attracted great attention and new rhodium-based catalysts have recently been developed for this reaction. The authors show that ultrahigh vacuum experiments can provide significant information on the single reaction steps, thus shedding light on the underlying chemical mechanisms (see picture).

    8. Noniterative Biexponential Fluorescence Lifetime Imaging in the Investigation of Cellular Metabolism by Means of NAD(P)H Autofluorescence (pages 1141–1149)

      Raluca Niesner, Bülent Peker, Peter Schlüsche and Karl-Heinz Gericke

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400066

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      Mapping metabolism: The authors employ biexponential fluorescence lifetime imaging in order to discriminate between free and protein-bound NAD(P)H without any previous calibration. Thus, they directly obtain a high-resolution map of cellular metabolism (shown), that is, an image of the contribution of the protein-bound NAD(P)H to the cumulative NAD(P)H fluorescence signal. The evaluation of the biexponential decays was performed by means of a rapid noniterative approximation technique.

    9. Mechanical Properties of Single Motor Molecules Studied by Three-Dimensional Thermal Force Probing in Optical Tweezers (pages 1150–1158)

      Sylvia Jeney, Ernst H. K. Stelzer, Helmut Grubmüller and Ernst-Ludwig Florin

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200301027

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      Thermal forces do it all. A novel method based on optical tweezers, 3D position detection and thermal noise analysis provides detailed information about protein nanomechanics in three dimensions and at minimal external forces (≪pN). Here the flexibility of the motility-determining part of the molecular motor kinesin was studied while it was bound to a microtubule (see picture).

    10. Identification of Biotic and Abiotic Particles by Using a Combination of Optical Tweezers and In Situ Raman Spectroscopy (pages 1159–1170)

      R. Geßner, C. Winter, P. Rösch, M. Schmitt, R. Petry, W. Kiefer, M. Lankers and J. Popp

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400026

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      Raman spectroscopy on single cells: The combination of optical tweezers and vibrational spectroscopy offers a new tool for in situ Raman spectroscopy on single cells. The photograph displays a single red blood cell which is kept in a stable position by an optical gradient trap. The tip of the fiber probe is brought into close proximity of the cell and Raman excitation is applied at an extremely low laser power.

    11. The Excited-State Dynamics of Phycocyanobilin in Dependence on the Excitation Wavelength (pages 1171–1177)

      Benjamin Dietzek, Raman Maksimenka, Gudrun Hermann, Wolfgang Kiefer, Jürgen Popp and Michael Schmitt

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400056

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      The open-chain tetrapyrrole chromophore phycocyanobilin (PCB) is of importance as a model substance for a series of biological chromophores. In solution, three different PCB species, PCBA, PCBB, and PCBC, coexist in thermal equilibrium (see picture). By applying femtosecond-resolved transient grating and transient absorption spectroscopy, a recent kinetic model suggested for the excited-state processes in PCB was verified.

    12. Electrochemical Deposition of Platinum Nanoparticles on Carbon: A Study by Standard and Anomalous X-ray Diffraction (pages 1178–1184)

      Sébastien Adora, Jean Paul Simon, Yvonne Soldo-Olivier, René Faure, Eric Chaînet and Robert Durand

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200301048

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      Synchrotron X-ray diffraction in classical and anomalous dispersion modes is an alternative method for studying the growth of platinum nanoparticles. The authors have used the method for the straightforward determination of the mean diameter and surface concentration of carbon-supported, electrocrystallized platinum nanoparticles, even down to diameters of 2–3 nm and metal amounts of 0.03 mg cm−2. The roles of the different parameters influencing electrochemical deposition of the particles are discussed. The picture shows the XRD peaks of platinum nanoparticles and of the Toray carbon support.

    13. Adsorption of Amyloid Beta (1-40) Peptide to Phosphatidylethanolamine Monolayers (pages 1185–1190)

      Elena Maltseva and Gerald Brezesinski

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400045

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      Amyloid β peptide exhibits β-sheet secondary structure: Synthetic Aβ peptide adsorbs to uncompressed phosphatidylethanolamine monolayers in a similar way as to a pure air–water interface. Grazing incidence X-ray diffraction experiments show no influence of Aβ on the lipid structure, and no adsorption to hydrophilic head groups and penetration into highly compressed lipid monolayers was observed by IR reflection absorption spectroscopy (see graphic).

    14. The State of the Iron Promoter in Tungstated Zirconia Catalysts (pages 1191–1199)

      Xavier Carrier, Povilas Lukinskas, Stefan Kuba, Lorenzo Stievano, Friedrich E. Wagner, Michel Che and Helmut Knözinger

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400046

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      Promoter positions ironed out: EXAFS at the Fe K-edge (see graphic), XANES, EPR, and Mössbauer spectroscopies show that FeIII forms a surface solid solution with tetragonal zirconia in tungstated zirconia catalysts used for n-alkane isomerization.

    15. A Novel Fluorophore with Dual Fluorescence: Local Excited State and Photoinduced Electron-Transfer-Promoted Charge-Transfer State (pages 1200–1209)

      Viruthachalam Thiagarajan, Chellappan Selvaraju, E. J. Padma Malar and Perumal Ramamurthy

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400064

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      Fluorescence goes both ways: Dual emitting decahydroacridinedione dye (DMAADD) is a new fluorescent probe for transition metal ions by fluorescence enhancement via photoinduced electron transfer. The photoinduced electron transfer from the donor to the excited state of ADD produces a low-lying intramolecular charge-transfer state (see graphic), which results in an anomalous longer wavelength emission.

    16. Self-Assembly and Characterization of Hydrogen-Bond-Induced Nanostructure Aggregation (pages 1210–1215)

      Yang Liu, Junpeng Zhuang, Huibiao Liu, Yuliang Li, Fushen Lu, Haiyang Gan, Tonggang Jiu, Ning Wang, Xiaorong He and Daoben Zhu

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400165

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      A supramolecular system of a perylene derivative containing bis(2,6-diacylaminopyridine) units and a perylene bisimide bound by three hydrogen-bonding interactions was synthesized and characterized. SEM images indicated that the supramolecular system can form fibrous nanostructures (see picture) with diameters in the range of 40–100 nm and lengths of several micrometers. Films of the supramolecular system were shown to produce a photocurrent response.

    17. Reaction of para-Hydroxy-Substituted Diphenylmethanes with tert-Butoxy Radical (pages 1217–1221)

      Catarina F. Correia, Rui M. Borges dos Santos, Sílvia G. Estácio, João P. Telo, Benedito J. Costa Cabral and José A. Martinho Simões

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400044

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      What is the outcome of this reaction? In acetonitrile solution, the methylenic C[BOND]H bond is approximately 25 kJ mol−1 weaker than the O[BOND]H bond in the same molecule (see picture), as demonstrated by time-resolved photoacoustic calorimetry and quantum chemical methods. However, as shown by electron spin resonance spectroscopy, the tert-butoxy radical selectively abstracts the hydrogen atom from the OH group.

    18. Effect of pH and Alkaline Metal Cations on the Voltammetry of Pt(111) Single Crystal Electrodes in Sulfuric Acid Solution (pages 1221–1227)

      Nuria García, Víctor Climent, José M. Orts, Juan M. Feliu and Antonio Aldaz

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400047

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      Cation effects: The role of alkaline cations on the double layer structure is demonstrated (see graphic). The effect of the pH value and the nature and concentration of the cation on the voltammetric fingerprint of Pt(111) in sulfuric acid solution is pointed out.

    19. Unusual Redox Catalysis in a Ruthenium Oxide–Prussian Blue Combined Material (pages 1227–1231)

      Annamalai Senthil Kumar and Jyh-Myng Zen

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400068

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      A stable high-valent RuVII: In pH<12 aqueous solutions, ruthenium tends to convert into lower oxidation states due to the disproportionation-decomposition reaction (DDR) shown. For the first time the novel stabilization of RuVII (as >RuVII[DOUBLE BOND]O) was identified in a ruthenium oxide–Prussian blue (RuOx–PB) analogue in an acidic medium (pH 2) without any DDR. The RuOx–PB can selectively catalyze the oxidation of glucose (G) to gluconolactone (GO).

    20. Formation and Decomposition of Phenylvinylperoxy Radicals in the Reaction: C6H5C2H2+O2 (pages 1231–1234)

      Y. M. Choi, J. Park, Liming Wang and M. C. Lin

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400087

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      Radical pathways: Experimental and theoretical spectroscopic and kinetic data for the phenylvinyl radical and its oxidation product (see picture), and two key pathways for the C6H5C2H2+O2 reaction are presented.

    21. Experimental Validation of Marcus Theory for Outer-Sphere Heterogeneous Electron-Transfer Reactions: The Oxidation of Substituted 1,4-Phenylenediamines (pages 1234–1240)

      Antony D. Clegg, Neil V. Rees, Oleksiy V. Klymenko, Barry A. Coles and Richard G. Compton

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400128

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      Rate constants depend on molecular size: Results are presented to validate the relationship between molecular size and the standard electrochemical rate constant predicted by Marcus theory (see graphic). Measurement of hydrodynamic radii and electron-transfer rates for substituted 1,4-phenylenediamines have been made under steady-state conditions using both hydrodynamic and stationary electrodes.

    22. First Direct Observation of the Higher Triplet Excited States of Substituted Oligothiophenes by Two-Color Two-Laser Flash Photolysis (pages 1240–1242)

      Mamoru Fujitsuka, Yosuke Oseki, Michihiro Hara, Xichen Cai, Akira Sugimoto and Tetsuro Majima

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400169

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      The higher triplet excited states (Tn) of oligothiophenes [trimer (3T), tetramer (4T), and pentamer (5T)] were directly observed for the first time during two-color two-laser flash photolysis employing a picosecond laser. The lifetimes of the Tn states of the oligomers were a few tens of picoseconds. The internal conversion between T2–T1 is the rate-determining step for the oligothiophenes (see picture).

    23. Application of Hole Theory to the Viscosity of Ionic and Molecular Liquids (pages 1242–1246)

      Andrew P. Abbott

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400190

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      Holey waters: The viscosity of a range of ionic and molecular fluids is shown to be proportional to the probability of finding an adjacent hole of sufficient dimensions to permit movement. An expression for the viscosity of an ideal gas can be modified by this probability function to account for the viscosity of liquids (see graphic).

    24. Novel Lipid Nanotubes in Dispersions of DMPC (pages 1246–1249)

      Ulrike Lauf, Alfred Fahr, Kirsten Westesen and Anne S. Ulrich

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200400235

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      A screwlike rippled surface is a unique feature of the lipid nanotubes (see picture) that formed spontaneously in a dispersion of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC). Their unusual morphology may be explained by a kinetically trapped state after many small unilamellar vesicles have undergone fusion.

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      Preview: ChemPhysChem 8/2004 (page 1254)

      Version of Record online: 10 AUG 2004 | DOI: 10.1002/cphc.200490045