ChemPhysChem

Cover image for ChemPhysChem

July 14, 2003

Volume 4, Issue 7

Pages 653–778

    1. Cover Picture: Role of Temperature in Controlling Performance of Photorefractive Organic Glasses (ChemPhysChem 7/2003) (page 653)

      Oksana Ostroverkhova, Meng He, Robert J. Twieg and W. E. Moerner

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200390084

    2. Graphical Abstract: ChemPhysChem 7/2003 (pages 655–660)

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200390085

    3. A Half-Century with Solar Neutrinos (Nobel Lecture) (pages 662–671)

      Raymond Davis, Jr.

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300806

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      Made from stars: Neutrinos, which are formed in the fusion processes in the Sun and other stars when hydrogen is converted into helium, hardly interact at all with matter and are therefore very difficult to detect. For example, thousands of billions of neutrinos pass through us every second without our noticing them. The author constructed a completely new detector (see construction picture) and, over a period of 30 years, he succeeded in capturing a total of 2 000 neutrinos from the Sun and was thus able to prove that fusion provided the energy from the Sun.

    4. Birth of Neutrino Astrophysics (Nobel Lecture) (pages 672–679)

      Masatoshi Koshiba

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300773

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      A difficult child: The author was instrumental in the birth and early development of neutrino astrophysics. The KamiokaNDE and Super-KamiokaNDE experiments for the detection and observation of solar and supernova neutrinos are discussed, from conception through to recent results of ongoing work. Now the energies and oscillation parameters of neutrinos and antineutrinos can be measured; with this information, we can develop pictures of the sun (see left), and should one day be able to understand the state of the universe one second after its birth.

    5. The Dawn of X-Ray Astronomy (Nobel Lecture) (pages 680–690)

      Riccardo Giacconi

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300751

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      The importance of astronomy: The author was awarded half of the 2002 Nobel Prize in Physics for “pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources”. Xray photons are particularly suited to study these processes because they are numerous, because they penetrate cosmological distances, and because they can be focused by special telescopes. High-energy astronomy has great importance in the study of the Universe (see picture: picture of the Sun taken using the Xray emissions), and because high-energy phenomena play a crucial role in the dynamics of the Universe.

    6. Metallobiliverdin Radicals—DFT Studies (pages 691–698)

      Ludmiła Szterenberg, Lechosław Latos-Grażyński and Jacek Wojaczyński

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200200611

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      Heme breakdown: DFT calculations performed for metallobiliverdin radicals gave some insight into the electronic structure of iron biliverdin complexes—important intermediates in the heme degradation process. The picture shows a plot of the surface of constant spin value for the zinc biliverdin radical.

    7. Cell Adhesion onto Highly Curved Surfaces: One-Step Immobilization of Human Erythrocyte Membranes on Silica Beads (pages 699–704)

      Stefan Kaufmann and Motomu Tanaka

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200200537

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      A sticky situation: A simple method to immobilize cell membranes is presented: incubating erythrocytes with silica beads (d=3 μm) leads to cell adhesion and rupture, as well as spreading of the membranes over the beads, without any need for osmotic lysis or sonication to induce membrane disruption. Immunofluorescence studies (picture) with specific labels for the innner and outer membrane surfaces revealed that all cells underwent inversion of their orientation on binding.

    8. Myristyl Dimethylamine Oxide Surfactant Solutions: Model Systems for Rheological Research (pages 705–713)

      Manuela Pflaumbaum and Heinz Rehage

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200200585

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      Go with the flow: The authors present a detailed study of the nonlinear rheological properties of aqueous myristyl dimethylamine oxide surfactant solutions (see picture). The phenomena discussed are of scientific and practical interest, and occur in a similar way in a large number of colloidal systems, such as polymer solutions, dyes, foams, emulsions, and suspensions.

    9. Redox and Conformational Equilibria and Dynamics of Cytochrome c at High Electric Fields (pages 714–724)

      Hainer Wackerbarth and Peter Hildebrandt

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200200618

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      Electric fields control interfacial processes of proteins at biomembranes. Such effects can be mimicked for proteins adsorbed on electrodes and studied by surface-enhanced resonance Raman spectroscopy. For the redox protein cytochrome c (see picture), it is shown that strong electric fields can have a pronounced influence on the molecular structure and the thermodynamics and kinetics of the interfacial electron-transfer reactions and coupled conformational transitions.

    10. Experimental and Quantum-Chemical Studies on the Thermochemical Stabilities of Mercury Carbodiimide and Mercury Cyanamide (pages 725–731)

      Xiaohui Liu, Paul Müller, Peter Kroll, Richard Dronskowski, Wolfgang Wilsmann and Reinhard Conradt

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300635

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      The first representatives of a solid-state carbodiimide/cyanamide polymorphism (see picture) are mercury carbodiimide HgNCN(I) and mercury cyanamide HgNCN(II). In harmony with Pearson's hard and soft acids and bases (HSAB) concept, calorimetric measurements evidence that the cyanamide species is more stable, but only by a tiny quantity. The experimental data furthermore reveal that stability rankings for the above solids by means of density functional calculations are incorrect. Detailed comparisons with highly correlated quantum-chemical methods point towards a serious flaw in ordinary exchange-correlation functionals.

    11. Role of Temperature in Controlling Performance of Photorefractive Organic Glasses (pages 732–744)

      Oksana Ostroverkhova, Meng He, Robert J. Twieg and W. E. Moerner

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200200633

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      Optimizing photorefractive glasses: Monolithic, photorefractive (PR) glasses that are based on new nonlinear-optical chromophores containing a 2dicyanomethylene-3-cyano-2,5-dihydrofuran (DCDHF) acceptor group (see picture) exhibit large net two-beam coupling gain coefficients. However, the photorefractive dynamics are slow and are orientationally limited at temperatures around the glass transition. The temperature dependence of dielectric, birefringent, conductive, and photorefractive properties of DCDHF glasses is presented. Fine-tuning the operating temperature within several degrees above the glass transition can significantly improve PR dynamics while maintaining high steady-state performance.

    12. Triple FRET: A tool for Studying Long-Range Molecular Interactions (pages 745–748)

      Elke Haustein, Michael Jahnz and Petra Schwille

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200200634

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      Molecular traffic lights: A FRET cascade involving three spectrally suitable dyes (see picture) is not only feasible, but the effective distance can easily be increased to 100 Å and beyond; this was previously inaccessible with conventional FRET measurements.

    13. Single- and Multiple-Molecule Dynamics of the Signaling from H-Ras to cRaf-1 Visualized on the Plasma Membrane of Living Cells (pages 748–753)

      Kayo Hibino, Tomonobu M. Watanabe, Jun Kozuka, Atsuko Hikikoshi Iwane, Tomoyo Okada, Tohru Kataoka, Toshio Yanagida and Yasushi Sako

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300731

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      It's alive! The authors investigated the molecular behavior of the enzyme GFP-Raf1 in response to epidermal growth factor in living HeLa cells, using multiple- and single-molecule fluorescence microscopy. The interaction between YFP-Ras and GFP-Raf1 was detected using fluorescent resonance energy transfer imaging (see picture). Single-molecule observations point to a locally heterogeneous signaling process between Ras and Raf1.

    14. G2 and DFT Rigorous Description of the Inversion Process of Oxane and Thiane used as Simple Ring Systems to Model Sugar Components (pages 754–757)

      María del Carmen Fernández-Alonso, Juan Luis Asensio, Francisco J. Cañada, Jesús Jiménez-Barbero and Gabriel Cuevas

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200200547

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      Comfy seats: Deformation of the pyranose chair is involved in catalysis by carbohydrate-processing enzymes. Basic models of these rings have been studied, at different levels of theory. The chair inversion processes of oxane and thiane (see picture) occurs in two steps with a skewed boat intermediate that suffers a topoisomerization through a boat conformer. There are two transition states associated with the inversion process, in which the heteroatom and methylene C4 atom are on the plane generated by the neighboring atoms, that are closer to a “sofa” than to a half-chair.

    15. Second Harmonic Generation and Fluorescence of CMONS Dye Nanocrystals Grown in a Sol-Gel Thin Film (pages 757–760)

      François Treussart, Estelle Botzung-Appert, Nguyet-Thanh Ha-Duong, Alain Ibanez, Jean-François Roch and Robert Pansu

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300681

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      CMONS: an alternative to fluorescent probes? Nanocrystals of CMONS dye (see picture), about 100 nm in diameter, were grown in a sol-gel thin film. The authors selectively grew the non-centrosymmetric form in order to study the nanocrystals' nonlinear properties. Using scanning optical microscopy, the two-photon induced fluorescence and the second harmonic generation (SHG) signals. (shown) were simultaneously mapped. Time-resolved fluorescence spectroscopy on a single nanocrystal yielded an excited-state relaxation time that is about twenty times smaller than that of a microcrystal, taken as the reference for bulk. This can be explained by the photoinduced isomerization of the stilbene-like CMONS molecules localized at the surface of the nanocrystal.

    16. A Simple Aqueous-Solution Processing Route to Prepare Quantum-Confined CdS Nanorods (pages 761–763)

      Wenlong Wang and Fenglian Bai

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300727

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      A straightforward, aqueous processing route was demonstrated for the bulk synthesis of single crystalline CdS nanorods with their lateral diameters in the quantum-confined size region (see picture). This new, aqueous growth method is, in contrast to existing approaches for preparing 1D semiconductor nanocrystals, experimentally simple, much less expensive and more environment-friendly.

    17. Experimental and Theoretical Characterization of a Triplet Boron Carbonyl Compound: BBCO (pages 763–766)

      Mingfei Zhou, Zhi-Xiang Wang, Paul von Ragué Schleyer and Qiang Xu

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300736

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      Unusually generous donation: Matrix isolation infrared spectroscopy and quantum chemical calculations characterize the new boron carbonyl compound BBCO (see graphic), which has a linear triplet ground state (3Π∏). The binding energy of CO and BB is quite large, due to the back bonding usually associated with transition metal carbonyl complexes.

    18. The Interplay of Aryl–Perfluoroaryl Stacking Interactions and Interstack Hydrogen Bonding in Controlling the Structure of a Molecular Cocrystal (pages 766–769)

      Siwaporn Meejoo, Benson M. Kariuki and Kenneth D. M. Harris

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200300762

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      Stacks of molecules: Structural properties of a 1:1 cocrystal formed between phenol and pentafluorophenol have been investigated by powder neutron diffraction. There are three crystallographically independent stacks which engage in interstack O[BOND]H⋅⋅⋅O hydrogen bonds to form a hydrogen-bonded loop involving six OH groups (see picture). The H atom of each OH group is disordered between two positions, corresponding to two different hydrogen-bonding arrangements within the loop.

    19. Preview: ChemPhysChem 7/2003 (page 778)

      Article first published online: 7 JUL 2003 | DOI: 10.1002/cphc.200390089

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