Materials Literature
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MgO cubes coated by graphitic carbon are formed in addition to multiwalled carbon nanotubes after reaction of Mo(CO)6 with Mg at 900 °C. The edges of these cubes are 500–600 nm in length and in some cases the MgO inside the cube can be dissolved to leave carbon cubes as the sole product. The Figure shows an area rich…
Several unsymmetrically substituted aromatic donor–acceptor disulfides have been synthesized and analysed for their second order nonlinear optical properties. These molecules exhibit moderately high first hyperpolarizability (β) with excellent transparency in the visible region. Most of the unsymmetrical disulfides ha…
Zucker-Rezeptoren: Porphyrine, die mit einem Harnstoff verknüpft sind, können Pyranoside in Chloroform besonders gut binden, sogar in Gegenwart von Hydroxygruppen enthaltenden Cosolventien. Die starre Anordnung des nichtflexiblen Porphyrin-Grundgerüsts mit den acyclischen, beweglichen, polaren und bereits vororganisie…
The selective catalytic reduction (SCR) of NO by NH3 in the presence of O2 on Cu-faujasite (Cu-FAU) has been studied. Substitution of some Cu2+ with H+ and Na+ cations, compensating for the negative charge of the zeolite framework, forms the various CuHNa-FAU studied. The amount of Cu was held constant and the proport…
The dissolution process of poly(methyl methacrylate) in mixtures of methanol and carbon tetrachloride, individually nonsolvents for the polymer (under the conditions of study), was studied at 25 °C using FTIR imaging spectroscopy. To investigate this cosolvency phenomenon, the spatial resolution and sensitivity of FTI…
The use of a crown-ether-linked merocyanine, DCM-crown, for producing photoinduced, long-lived and reversible concentration jumps of metal cations is reexamined. In this new investigation, the excited-state behavior of DCM-crown complexed with a strontium ion in acetonitrile is found to exhibit the same trends as thos…
An aqueous emulsion containing ionic Co2+ and Br- species stabilised by fluorous surfactant-like species in supercritical CO2-air mixture acts as a nano-reactor with excellent interfacial contacts of all necessary hydrophilic/hydrophobic species, which renders safe operation of catalytic aerial oxidation of toluene at…
A remarkably anisotropic structure is exhibited by [Cu26(hfac)11(1-pentynyl)15] (hfac=hexafluoroacetylacetone), the largest CuI cluster to have been isolated (see picture). A variety of copper–alkynyl bridging modes are found within the disc-shaped cluster, with all but one of the 26 Cu atoms being located in either o…
Sugar receptors: Urea-appended porphyrins were the most effective binding agent for pyranosides in chloroform and still very effective even in the presence of hydroxylic cosolvents. The combination of a rigid porphyrin skeleton and acyclic, flexible, yet preorganized polar urea groups aligned in a rigid platform (see…
The ground state electronic structure of the mixed-valence systems [Ni(2)(napy)(4)X(2)](BPh(4)) (napy=1,8-naphthyridine; X=Cl, Br, I) was studied with combined experimental (X-ray diffraction, temperature dependence of the magnetic susceptibility, and high-field EPR spectroscopy) and theoretical (DFT) methods. The zer…
Eine lamellare Hybrid-Mesostruktur mit polymerisierbaren Diacetylengruppen wird bei der In-situ-Synthese von Siliciumdioxid durch saure Hydrolyse und Kondensation von Tetraethylorthosilicat (TEOS) in Gegenwart von 1,2-Bis(10,12-tricosadiinonyl)-sn-glycero-3-phosphatidylcholin (DC8,9PC) gebildet. Diese Mesostruktur lag…
We have developed a new class of synthetic membranes that consist of a porous polymeric support that contains an ensemble of gold nanotubes that span the thickness of the support membrane. The support is a commercially-available microporous polycarbonate filter with cylindrical nanoscopic pores. The gold nanotubes are…
We studied the temperature and pressure dependence of the phonons of the two different phases of $(\mathrm{VO}{)}_{2}{\mathrm{P}}_{2}{\mathrm{O}}_{7},$ the ambient (AP) and the high-pressure (HP) phase, by polarized Raman spectroscopy. Most modes in the lower-symmetry AP phase are split compared to the higher-symmetry…
Quasielastic x-ray scattering from thermally populated phonons in crystalline niobium was recorded using a charge-coupled device over a large angular range. The patterns, displayed on a logarithmic intensity scale, reveal rich features. Theoretical patterns based on a lattice dynamics calculation are generated, and a…
The glass transition behavior of dried polystyrene (PS) samples adsorbed on silica, originally cast from carbon tetrachloride, has been studied using modulated differential scanning calorimetry (MDSC). The adsorbed amounts of the polymers on silica were very small, ranging from about 2 to 0.4 mg polymer/m 2 silica. Th…
A post-synthesis hydrothermal restructuring method is introduced as a convenient route to synthesize high quality MCM-48 silica with controllable pore size. Using tetraethyl orthosilicate as the silica source and cetyltrimethylammonium bromide (CTAB) as the template, the pore size could be tailored from 2.6 to 4.2 nm…
The adsorption state of ammonia (NH 3 ) on the ZnO(101̄0) surface has been investigated using photoelectron spectroscopy (PES) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The core-level and valence-band PES measurements reveal that ammonia adsorbs molecularly via its N atom on ZnO(101̄0) and t…
In-situ observations of crystallisation in minerals and organic polymers have been made by simultaneous, time-resolved small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) techniques. In isotactic polypropylene slow quiescent crystallisation shows the onset of large scale ordering prior to crysta…
A new conjugated copper-complexed polyrotaxane has been prepared by electropolymerization of a thiophene derivative; the rings are threaded onto a multi-1,10-phenanthroline (phen) axle, copper(I) acting as a template. The presence of CH3 groups ortho to the nitrogen atoms of the phen nuclei belonging to the conjugated…
Fluorescence decay curves for the ${}^{4}{\stackrel{\ensuremath{\rightarrow}}{{G}_{5/2}}}^{6}{H}_{7/2}$ transition of ${\mathrm{Sm}}^{3+}$ ions in lithium fluoroborate glasses for different lanthanide concentrations have been measured as a function of pressure up to 21 GPa at room temperature. At ambient conditions, f…