Materials Literature
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Die Umlagerung der Ag4-Clusterkerne der lumineszierenden Silber(I)-Komplexe mit Bis(diphenylphosphanyl)bipyridin (P2-bpy), die bei der Bindung von zusätzlichen Liganden an die Ag-Zentren erfolgt (siehe Bild), führt zur Löschung der Emission. Die Löschung tritt mit O2, CO, NO und mit koordinierenden Lösungsmitteln wie…
Materials that develop large shape changes in the magnetic field at a short response time provide a new method of producing motion and force in electromechanical devices. The strains are based on the magnetic-field-induced reorientation of the twin variants of the material. This effect is called magnetic shape memory…
Die stufenweise Desalkylierung von meso-Octaethylporphyrinogen 1 liefert Porphomethen 2 und Porphodimethen 3, wodurch große Mengen dieser wertvollen Zwischenprodukte zugänglich werden. Die Synthesesequenz beruht auf der Reaktion mit SnCl4⋅2 THF, Li und H2O; das Ausmaß der Desalkylierung hängt von der eingesetzten Meng…
Despite the high neutron absorption of natural europium, the crystal structures of two Eu hydrides could be solved from powder diffraction data. EuMg2D6 crystallizes in a novel AB2X6 structure type (see picture), EuMgD4 is isotypic to BaZnF4. The mean Eu−D distances are 258 and 253 pm, respectively.
... This paper describes a practical engineering approach and compares predictions with the results from several experimental studies.
Large magnetic field induced strain shave been reported in ferromagnetic shape memory alloys. two such alloys, Ni-Mn-Ga and Fe-Ni-Co-Ti are explored. A single crystal of Ni-Mn-Ga is shown to deformed by bending approximately six degrees under the influence of an applied field. This deformation is caused by the motion…
Lanthanide, main group, and transition metal ion templates provide different polynuclear cages from [M(L)] (M=Ni, Mn; (L)2−=CH2[CH2N=C(CH3)COO−]2). Templating with lanthanum results in a 12-coordinate LaIII ion encapsulated by six [Ni(L)] units, whereas with sodium four Na+ ions are trapped inside a tricapped trigonal…
A new type of heterogeneous, polystyrene-bound catalyst is introduced: A cross-linking, dendritic ligand, the TADDOL 1, is copolymerized with styrene, loaded with titanate, and used for the enantioselective catalysis of the addition of Et2Zn to PhCHO. The polymer-bound catalyst has an unprecedented efficiency and stab…
We have observed the electronic states at conducting polymer/conducting oxide interfaces using a low-energy photoelectron spectroscopic method. The electronic states of conducting polymer/indium tin oxide (ITO) interfaces were different from those of conducting polymer/metal interfaces. The electron transfer from a co…
The acid-catalyzed ammonolysis of the hitherto unknown compound tris(dimethylamino)silylamine (1), which is prepared from SiCl4 in high yield and purity, results in the preparation of a silicon diimide gel. The probable first step in this process is the acid-catalyzed self-condensation of 1 to the cyclic trimer [{(CH3…
⋅2 THF employed.
Hydrothermal synthesis provides new vanadium borophosphates. BP2O10 trimers and V2O8 dimers are connected by common oxygen atoms to give a building unit of composition (VO)2BP2O10. Four-, five-, and six-rings are formed by further connection of these units; the first case is shown schematically. The ring size of the a…
Based on density functional theory the influence of curvature on the depletion potential of a single big hard sphere immersed in a fluid of small hard spheres with packing fraction ${\ensuremath{\eta}}_{s}$ either inside or outside of a hard spherical cavity of radius ${R}_{c}$ is calculated. The relevant features of…
First model-independent measurements of the hydrogen diffusivity $D$ in lanthanum trihydrides ${\mathrm{LaH}}_{x}$ $(2.00\ensuremath{\le}x\ensuremath{\le}3.0)$ have been performed by PFG-NMR. At a fixed concentration $x\ensuremath{\le}2.92$, $D(T)$ shows single Arrhenius behavior over wide temperature ranges. The acti…
The popular “high-electric-field” technique to determine the polar anchoring coefficient W of a nematic–substrate interface requires the simultaneous measurement of the capacitance and optical phase retardation of a liquid crystal cell as a function of applied voltage. We develop a generalized model that makes it poss…
The somewhat "exotic" pentafluorosulfuranyl functionality is one of the strongest electron-withdrawing groups with a purely inductive effect. Owing to its chemical stability and the resulting high dipole moment of its aromatic derivatives, this group was crucial to the design and synthesis of a new class of highly pol…
Rearrangement of the Ag4 cores of the luminescent silver(I) bis(diphenylphosphanyl)bipyridine (P2-bpy) complexes shown upon ligation of the Ag centers (see picture) leads to quenching of their emissions. Quenching occurs with O2, CO, NO, and with coordinating solvents such as MeCN and Me2SO. The reversible quenching o…
Highly [100]-axis oriented single-phase Na0.5K0.5NbO3 (NKN) thin films have been grown on polycrystalline Pt80Ir20 (Pt) and SiO2 (native oxide)/Si (111) substrates using KrF excimer laser ablation of a stoichiometric ceramic target. X-ray diffraction θ–2θ scan and rocking curve data are evidence of the strong effect o…
Photoluminescence (PL) from Si nanocrystals (nc-Si) dispersed in phosphosilicate glass thin films was studied. It was found that, at room temperature, the 1.4 eV PL due to the recombination of electron-hole pairs in nc-Si becomes intense as the P concentration increases. At low temperatures, an additional peak related…
Controlled room-temperature photoluminescence (PL) and electroluminescence (EL) from porous silicon (PSi) multilayer structures are achieved. The basic structure is composed of two PSi multilayer mirrors sandwiching a highly luminescent PSi film. This creates an active microcavity resonator, in which a significant PL…