Materials Literature
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The synthesis, characterization, and mesomorphic properties of new discotic molecules based on the triazolephthalocyanine macrocycle are described. This core has been attached to six lipophilic chains, and metallic complexes (Ni, Cu) have been prepared. The mesogenic behavior has been studied using optical microscopy,…
Thermoluminescence (TL) and radio-thermoluminescence spectral analysis techniques have been applied to doped calcium sulphate samples designed for radiation measurements at elevated temperatures. CaSO 4 :Dy, when co-doped with Ag, provides a TL dosimetric peak near 350 °C which is useful for radiation measurements at…
A new one-dimensional gallium phosphate−diphosphate, [C 2 H 10 N 2 ][Ga(H 2 PO 4 )(P 2 O 7 )], has been synthesized under solvothermal conditions at 433 K in the presence of ethylenediamine, and the structure was determined using room-temperature single-crystal X-ray diffraction data ( M r = 402.76, monoclinic, space…
Die Kontrolle über die Selbstorganisation von Cobaltporphyrin-Polymeren lässt sich durch Gelchromatographie prüfen: Die Polymere bilden sich aus Cobaltporphyrinen, die mit zwei potentiell koordinierenden Pyridinarmen versehen sind; die Molekülmassen in Lösung betragen 100 kDa und mehr. Die mittlere Molekülmasse lässt…
The acidic lactonization and alkaline hydrolysis of the title compound, a model for biologically important polyneuraminic acid derivatives, were investigated. The results indicate that initial lactonization takes place mostly at the internal position B en route to the trilactone 1.
Der Unterschied in den Relaxationsgeschwindigkeiten von Wasserprotonen wird durch ein Kontrastreagens für die Magnetresonanz-Bildgebung (magnetic resonance imaging, MRI) verstärkt: Die Oxidation der Manganzentren im supramolekularen Addukt aus Poly-β-cyclodextrin (PolyβCD) und [MnII(tpps)]4− führt zu einer deutlichen…
Highly conductive hybrid Langmuir−Blodgett (LB) films of MoS 2 and amphiphilic compounds such as alkylammonium halides and alkylamines were fabricated. The interlayer spacing of the LB films depended on the organic species. The lateral conductivity of 10-layer LB films was in the range of 10 1 to 10 2 S cm - 1 and dec…
Exchange coupling constants for di-μ-oxo-bridged copper(II) dimers with varying Cu−O−Cu bond angles have been calculated by means of density functional, broken symmetry (BS) techniques. The surprinsingly large ferromagnetism recently computed by Ruiz et al. [ Chem. Commun. 1998, 2767] for such model complexes has been…
Chemical transport experiments are a valuable aid of great potential in the synthesis and thermochemical characterization of solids. Compounds of interest can often only be crystallized by this method. The use of a transport balance allows very detailed observations, particularly of the course of the experiment over t…
The transient kinetics of the reaction between NO and CO on clean Rh(111) surfaces have been studied using molecular beams in conjunction with mass spectrometry detection. The changes in the partial pressures of the reactants (CO and NO) and products (N 2 and CO 2 ) as a function of time have been used as a measure of…
The homologous dendrimers G0 to G3, which consist of 3, 9, 21, and 45 viologens, behave as electron sponges and exhibit an electrochemically switchable, generation-dependent, intramolecular charge transfer (CT) complexation (see schematic diagram of G3).
The ring-opening polymerization of ε-caprolactone has been initiated by [tris(hexamethyldisilyl)amide]yttrium in the presence of an excess of 2-propanol. This initiating system is very active even at high alcohol-to-Y molar ratio. Polymers with controlled molecular parameters ( M n, end groups) and low dispersity are…
A self-assembly layer-by-layer (LBL) technique was used for the sequential adsorption of polycation, poly(diallyldimethylammonium chloride) (PDDA) and polyanion, sulfonated polyaniline (SPANI) on glass, indium-tin-oxide (ITO) coated glass plates, polystyrene sulfonate (PSS)/glass and PSS/ITO surfaces, respectively. Th…
A coupling of size exclusion chromatography (SEC) and liquid chromatography at the critical adsorption point (LC CAP) has been applied to simultaneous discrimination of stereoregular poly(ethyl methacrylate)s (PEMAs) according to their molar mass and tacticity. The two-dimensional SEC/LC CAP separations were carried o…
Thin films of solvent-free molecule-based magnets [Cp*2Fe]•+[TCNE]•- and V(TCNE)x are grown by chemical vapor deposition on KBr pellets. [Cp*2Fe]•+[TCNE]•- films are crystalline and magnetically order at 3.7 K. Despite of their faceted grain morphology, V(TCNE)x films are amorphous. They exhibit field-dependent magnet…
Photoelectrochemical cells have been constructed by depositing monolayers of oriented covalently linked zinc/free base porphyrin heterodimers onto ∼30 nm nonporous layers of TiO 2 on ITO, deposited by metal−organic chemical vapor deposition (MO-CVD), and onto ∼100 nm porous, nanostructured TiO 2 layers, spin-coated fr…
The cure reactions of phenylethynyl end-capped polyimides were investigated using solid-state 13 C magic-angle spinning (MAS) nuclear magnetic resonance (NMR). A 13 C-labeled model compound ( 13 C-PEPA-3,4‘-ODA) and an imide oligomer ( 13 C-PETI-5) were synthesized and characterized. The thermal cure process for 13 C-…
The electrochemical and photophysical properties of a variety of neutral pi-associated [2]catenanes have been explored by using cyclic voltammetry, absorption and luminescence spectrophotometry and the measurement of exited-state lifetimes. Several trends that could be correlated with interactions between the mechanic…
Chemical oxidation of the linear tricobalt compound Co 3 (dpa) 4 Cl 2 ( 1 ) with 1 equiv of NOBF 4 yields the one-electron oxidized species [Co 3 (dpa) 4 Cl 2 ] + ( 1 + ), which crystallizes from dichloromethane as a solvate [Co 3 (dpa) 4 Cl 2 ][BF 4 ]·2CH 2 Cl 2 ( 2 ·2CH 2 Cl 2 ). The crystal structure of 2 · x CH 2…
The kinetic stability of the complex [Gd(DTPA)]2- (H5DTPA = diethylenetriamine-N,N,N',N",N"-pentaacetic acid), used as a contrast-enhancing agent in magnetic resonance imaging (MRI), is characterised by the rates of the exchange reactions that take place with the endogenous ions Cu2+ and Zn2+. The reactions predominan…