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Raman Spectroscopic Measurements of Scandium(III) Hydration in Aqueous Perchlorate Solution and ab Initio Molecular Orbital Studies of Scandium(III) Water Clusters: Does Sc(III) Occur as a Hexaaqua Complex?

Wolfram W. Rudolph、Cory C. Pye2000-02-05The Journal of Physical Chemistry A

We have shown that Sc(III) in aqueous perchlorate solution occurs as a hexaaqua cation. The weak, polarized Raman band assigned to the ν 1 (a 1g )(ScO 6 ) mode of the hexaaqua Sc(III) ion has been studied as a function of concentration. Besides the isotropic component at 442 cm -1, two weak depolarized modes at 295 an…

Spectroscopy and Quantum Chemical StudiesSolid-state spectroscopy and crystallographyChemical Synthesis and Characterization

Fibrous Assemblies Made of Amphiphilic Metallophthalocyanines

Mutsumi Kimura、Tsuyoshi Muto、Hideaki Takimoto 等 8 位作者2000-02-05Langmuir

A family of copper and zinc phthalocyanine-based amphiphililes possessing racemic and optically active diol units, ( rac )-ZnPc(OH) 16, ( rac )-CuPc(OH) 16, and ( S )-CuPc(OH) 16, have been synthesized. The self-assembling properties of these amphiphiles in aqueous solution have been studied by UV−vis, Fourier transfo…

Molecular Sensors and Ion DetectionSupramolecular Chemistry and ComplexesPorphyrin and Phthalocyanine Chemistry

Electron-phonon scattering in quantum wires exposed to a normal magnetic field

Mher M. Aghasyan、Samvel M. Badalyan、Garnett W. Bryant2000-02-05arXiv

A theory for the relaxation rates of a test electron and electron temperature in quantum wires due to deformation, piezoelectric acoustical and polar optical phonon scattering is presented. We represent intra- and inter-subband relaxation rates as an average of rate kernels weighted by electron wave functions across a…

Materials Science

Three-Strand Conducting Ladder Polymers: Two-Step Electropolymerization of Metallorotaxanes

Julio Buey、Timothy M. Swager2000-02-04Angewandte Chemie

Die sequentielle Polymerisation von supramolekularen Metallorotaxankomplexen führt zu dreisträngigen leitfähigen Polymeren. Dabei ist der innere Polymerstrang so zwischen den beiden anderen eingebunden, dass er als molekularer Draht vorliegt, der effektiv isoliert ist, wenn sich die äußeren Polymerstränge im nicht lei…

Conducting polymers and applicationsPorphyrin and Phthalocyanine ChemistryLuminescence and Fluorescent Materials

Investigation of the Hydration Kinetics of Novel Poly(ethylene oxide) Containing Polyurethanes

Rebecca Green、Siska Corneillie、Justine Davies 等 8 位作者2000-02-04Langmuir

We report on the study of the hydration of a series of poly(ether urethanes) of varying poly(ethylene oxide) content within their soft segments using surface plasmon resonance (SPR). The study of the extent and dynamics of polymer film swelling upon hydration by SPR reveals that the technique is sensitive to the influ…

Surface Modification and SuperhydrophobicityPolymer Surface Interaction StudiesForce Microscopy Techniques and Applications

Synthesis of Mesostructured Nickel Oxide with Silica

Xinghua Liu、C. M. Chun、İlhan A. Aksay 等 4 位作者2000-02-04Industrial & Engineering Chemistry Research

Mesostructured nickel oxide was formed with nickel sulfate and cationic surfactant cetyltrimethylammonium bromide (CTAB). X-ray diffraction (XRD) peaks at low scattering angles and transmission electron microscopy (TEM) indicated that a mesostructure was formed. However, these XRD patterns disappeared after calcinatio…

Supercapacitor Materials and FabricationCatalytic Processes in Materials ScienceMesoporous Materials and Catalysis

Anomalous Translational Diffusion: A New Constraint for Models of Molecular Motion Near the Glass Transition Temperature

Chia-Ying Wang、M. D. Ediger2000-02-04The Journal of Physical Chemistry B

A photobleaching technique has been used to measure the translational motion of tetracene in polystyrene near T g . The intermediate scattering function S ( q, t ) was observed to become increasingly non-exponential with decreasing temperature. Thus a clear transition from Fickian diffusion to non-Fickian translationa…

Phase Equilibria and ThermodynamicsMaterial Dynamics and PropertiesTheoretical and Computational Physics

Low Frequency Raman Active Vibrations in Fullerenes. 1. Monopolar Modes

Hans‐Jürgen Eisler、Stefan Gilb、Frank Hennrich 等 4 位作者2000-02-04The Journal of Physical Chemistry A

Raman measurements and PM3 calculations of low frequency (<600 cm - ) vibrational modes in a variety of different fullerenes can be rationalized in terms of the multipolar “acoustic” oscillations of isotropic spherical and spheroidal shells. In this first of a two part series, we show that all fullerene cages have mon…

Carbon Nanotubes in CompositesFullerene Chemistry and ApplicationsMechanical and Optical Resonators

Global Chirality in Rigid Decametallic Ruthenium Dendrimers

Mahn-Jong Kim、Frederick M. MacDonnell、Mary E. Gimon-Kinsel 等 6 位作者2000-02-04Angewandte Chemie International Edition

Metallodendrimers with ten chiral Ru centers have been prepared in a stereospecific fashion (see picture; *=chiral Ru(diimine)(3) center). These molecules are conformationally rigid and exhibit well-defined global topologies: some diastereomers exhibit macroscopically chiral structures, others show a disklike topology…

Metal complexes synthesis and propertiesDNA and Nucleic Acid ChemistryDendrimers and Hyperbranched Polymers

Al30: A Giant Aluminum Polycation

L. Allouche、Corine Gérardin、Thierry Loiseau 等 5 位作者2000-02-04Angewandte Chemie

Durch einfache hydrothermale Umsetzung des bekannten Aluminiumpolykations ε-Al13 erhält man die schematisch gezeigte, neuartige Al30-Spezies, das bislang größte Polykation. Dessen Charakterisierung durch Röntgenbeugungs- und NMR-Messungen ermöglichte auch die Zuordnung einiger bis dahin nicht identifizierter Signale i…

Metal-Organic Frameworks: Synthesis and ApplicationsPolyoxometalates: Synthesis and ApplicationsChemical Synthesis and Characterization

Doppeltmeso-β-verknüpfte Diporphyrine durch Oxidation von 5,10,15-Triaryl-substituierten NiII- und PdII-Porphyrinen

Akihiko Tsuda、Aiko Nakano、Hiroyuki Furuta 等 5 位作者2000-02-04Angewandte Chemie

Niedrigere Oxidationspotentiale als die monomeren Ausgangsverbindungen weisen die durch Ein-Elektronen-Oxidation mit Tris(4-bromphenyl)ammoniumhexachloroantimonat erhaltenen Diporphyrine [siehe z. B. Gl. (1)] auf. Dies und die stark rotverschobenen Soret-Banden der Produkte wiesen auf eine hohe Elektronenbeweglichkeit…

Porphyrin and Phthalocyanine ChemistryLuminescence and Fluorescent MaterialsMetal-Catalyzed Oxygenation Mechanisms

Ionochromic Effects and Structures of Metalated Poly(p-phenylenevinylene) Polymers Incorporating 2,2‘-Bipyridines

Lin X. Chen、W. Jäger、David J. Gosztola 等 5 位作者2000-02-04The Journal of Physical Chemistry B

The effects of metal ion chelation to the 2,2‘-bipyridine (bpy) groups on the photophysics and exciton dynamics of two conjugated polymers 1 and 2 in solution are investigated. The structures of polymers 1 and 2 have 2,2‘-bipyridyl-5-vinylene units that alternate with one and three 2,5-bis( n -decyloxy)-1,4-phenylenev…

Organic Electronics and PhotovoltaicsOrganic Light-Emitting Diodes ResearchConducting polymers and applications

Assembly of Silver(I) Polymers with Helical and Lamellar Structures

Mao-Chun Hong、Weiping Su、Rong Cao 等 5 位作者2000-02-04Chemistry - A European Journal

The new versatile multidentate nonchelating ligand 1,2-bis[(2-pyr-imidinyl)-sulfanylmethyl]benzene (bpsb) was designed and prepared for supramolecular syntheses. Self-assembly between silver nitrate and the bpsb ligand resulted in the polymer [Ag4(bpsb)2-(NO3)4]n (1) with a single-stranded helical chain structure. Eac…

Metal-Organic Frameworks: Synthesis and ApplicationsSupramolecular Self-Assembly in MaterialsNanocluster Synthesis and Applications

On the Location of Li+ Cations in the Fast Li-Cation Conductor La0.5Li0.5TiO3 Perovskite

J. A. Alonso、Jesús Sanz、J. Santamarı́a 等 6 位作者2000-02-04Angewandte Chemie

Lithiumionen befinden sich in der Mitte der Sauerstoff-„Fenster”︁ im Gerüst der eckenverknüpften TiO6-Oktaeder der Titelverbindung (siehe Bild), wie durch Neutronenbeugung gezeigt werden konnte. Die interatomaren Abstände werden dadurch optimiert, dass die Oktaeder etwas geneigt sind. Die ungewöhnliche Koordination un…

Ferroelectric and Piezoelectric MaterialsMicrowave Dielectric Ceramics SynthesisNuclear materials and radiation effects

Acid-Catalyzed 2-Furaldehyde (Furfural) Decomposition Kinetics

Ian Rose、Norman Epstein、A. P. Watkinson2000-02-04Industrial & Engineering Chemistry Research

Experiments on acid- (HCl-) catalyzed thermal decomposition of 2-furaldehyde in a dilute aqueous solution were performed in a stainless steel batch reactor over a temperature range of 130−170 °C. First-order reaction kinetics best described the experimental results. The rate of reaction increased with temperature and…

Catalysis for Biomass ConversionCatalysis and Hydrodesulfurization StudiesThermal and Kinetic Analysis

Simple Synthesis of a Chlorin - Fullerene Dyad with a Novel Ring-Closure Reaction

Franz‐Peter Montforts、Olaf Kutzki2000-02-04Angewandte Chemie International Edition

To model the photosynthetic reaction center, the chlorin - fullerene dyad 1 was synthesized in a one-pot reaction from a linear tetrapyrrole and C(60). It is the first dyad of this type which contains a fullerene and a chlorin unit, the chromophore of naturally occurring photosynthetic systems.

Porphyrin and Phthalocyanine ChemistryChemical Reactions and MechanismsHistory and advancements in chemistry

Hydrolytic Kinetics of Biodegradable Polyester Monolayers

Won‐Ki Lee、Joseph A. Gardella2000-02-04Langmuir

The rate of hydrolysis of Langmuir monolayer films of a series of biodegradable polyesters was investigated at the air/water interface. The present study investigated parameters such as degradation medium, pH, and time. The hydrolysis of polyester monolayers strongly depended on both the degradation medium used to con…

biodegradable polymer synthesis and propertiesMicroplastics and Plastic PollutionPolymer Surface Interaction Studies

Photochemistry of NO Chemisorbed on TiO2(110) and TiO2 Powders

C. N. Rusu、John T. Yates2000-02-04The Journal of Physical Chemistry B

The photodecomposition of chemisorbed NO has been studied using ultraviolet radiation of (3.96 ± 0.07) eV. Both the TiO 2 (110) single-crystal substrate and high area compressed TiO 2 powders have been investigated. A primary photoproduct is N 2 O gas, which desorbs immediately upon irradiation of the TiO 2 (110) surf…

Advanced Photocatalysis TechniquesCatalytic Processes in Materials ScienceGas Sensing Nanomaterials and Sensors

Radical Intermediates in the Jacobsen - Katsuki Epoxidation

Luigi Cavallo、Heiko Jacobsen2000-02-04Angewandte Chemie International Edition

Insight into the controversial mechanism of the Mn - salen-catalyzed epoxidation of olefins is provided in a theoretical study based on density functional theory. The calculations suggest that radical species A, but not manganaoxetanes B, are likely candidates for viable intermediates.

Polyoxometalates: Synthesis and ApplicationsMetal-Catalyzed Oxygenation MechanismsOxidative Organic Chemistry Reactions