Materials Literature
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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…
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…
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…
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…
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…
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…
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…
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…
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.
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…
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…
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.
Sequential polymerization of supramolecular metallorotaxane complexes results in three-stranded conducting ladder polymers. The internal polymer is "sandwiched" between the other two polymers to give molecular wires that are effectively insulated when the outer polymers are in their nonconducting state (shown schemati…
Infinite, extended chains or tetradecanuclear lanthanide clusters (see structure) can be formed, depending on conditions, from the reaction of potassium o-nitrophenolate with different lanthanide trichlorides.
Fluid assemblies of star-shaped molecules like 1 form a range of thermotropic liquid crystalline phases, and represent a borderline case between anisometric mesogens, surfactants, and block copolymers. The low molecular mass molecules (<5.5 kDa) consist of a semipolar central core and a shell of semifluorinated chains.
Lithium cations sit in the center of the oxygen "windows" defined by the vertex-sharing TiO(6) octahedra of the title compound (see picture), as shown from neutron diffraction data. The octahedra are tilted to optimize the bond distances between the atoms. The unusual coordination and the partially unoccupied sublatti…
To clarify the CO-tolerant mechanism at Pt-based alloy anode catalysts, surface-enhanced infrared reflection−absorption spectroscopy with the attenuated total reflection technique (ATR-SEIRAS), coupled with CV measurement, was used to observe the oxidation process of adsorbed CO on a typical Pt−Fe (Pt−Fe = 0.27/0.73)…
A new series of hybrid organometallic - inorganic layered magnets with the formula [Z(III)Cp*2][M(II)M(III)(ox)3] (Z(III) = Co, Fe; M(III) = Cr, Fe; M(II) = Mn, Fe, Co, Cu, Zn; ox = oxalate; Cp* = pentamethylcyclopentadienyl) has been prepared. All of these compounds are isostructural and crystallize in the monoclinic…
Geometries and band gaps of polyaniline oligomers up to decamer have been systematically calculated and analyzed using various computational techniques such as molecular mechanics, semiempirical, and ab initio methods. On the basis of fully optimized geometries of neutral and charged forms of polyaniline oligomers, ex…
The ring-opening polymerization of ethylene carbonate (EC) using KOH as initiator was investigated by changing the EC/KOH ratios and the reaction temperatures. The ratio of the rate of polymerization to chain scission increases as the temperature rises. Hydrolysis results and polymer composition data indicate that pol…