Materials Literature
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Two families of "push-pull" phthalocyanines 1-3 having an unusually strong dipole moment have been prepared. The syntheses of unsymmetrically substituted phthalocyanines 1a,b and 2 bearing one or two electron-withdrawing 4-nitrophenylethynyl moieties, respectively, and six alkoxy substituents were performed by combina…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis and First Structural Characterization of Lanthanide(II) Aryls: Observation of a Schlenk Equilibrium in Europium(II) and Ytterbium(II) ChemistryGernot Heckmann and Mark NiemeyerView Author Information Institut für Anorganische Chemie Universität Stuttgart Pfaf…
The 19 F 19 F nuclear spin−spin coupling constants J FF for a set of eighteen compounds related structurally to 1,8-difluoronaphthalene were measured by 19 F NMR spectroscopy. The FF distances d FF in these compounds were determined by ab initio 3-21G* molecular orbital calculations. Consistent with the lone-pair over…
The interactions of iodide ions with cuprite (Cu 2 O) surfaces were studied by combining batch experiments and surface analyses. The evolution of iodide uptake with pH was investigated. The thermodynamical calculations and surface analyses (X-ray photoelectron spectroscopy, scanning electron microscopy, Raman spectros…
The tunnel magnetoresistance (TMR) of F/O/F magnetic junctions, (F's are ferromagnetic layers and O is an oxide spacer) in the presence of magnetic impurities within the barrier, is investigated. We assume that magnetic couplings exist both between the spin of impurity and the bulk magnetization of the neighboring mag…
A polycrystalline and single-crystal samples of near-stoichiometric Ni2MnGa alloys have been investigated. It was confirmed that martensite short crystallographic axis (c-axis) is the easy axis of magnetization. The reversible reorientation of the easy magnetization direction of martensite samples after 5% compression…
Using analogies from nature, we investigated the possibility that tyrosinase-catalyzed reactions of 3,4-dihydroxyphenethylamine (dopamine) could confer water-resistant adhesive properties to semidilute solutions of the polysaccharide chitosan. Rheological measurements showed that the tyrosinase-catalyzed, and subseque…
Electric fields have been shown to orient nanoscopic domains laterally in thin copolymer films effectively. To achieve an orientation normal to the surface, interfacial interactions impose a barrier. Using asymmetric diblock copolymers of polystyrene (PS) and poly(methyl methacrylate) (PMMA) having cylindrical microdo…
Introduction: Novel Ultrahard Materials (A. Zerr & R. Riedel) STRUCTURES AND PROPERTIES Structural Chemistry of Hard Materials (W. Jeitschko, et al.) Phase Transitions and Material Synthesis using the CO 2 -Laser Heating Technique in a Diamond Cell (A. Zerr, et al.) Mechanical Properties and their Relation to Microstr…
At present, diblock copolymer phase behavior in the long-chain limit is considered to be governed by three factors: the volume fraction of one block, φ; the segregation strength of the diblock, χ N; and the conformational asymmetry parameter, ε. This implies that the phase diagrams for polymers of different chemistry…
We report the first synthesis of a stable complex of peroxynitrite coordinated to a transition-metal ion. Solid tris(tetraethylammonium) pentacyanosuperoxocobaltate(III) reacts with 1 equiv. of gaseous nitrogen monoxide to yield tris(tetraethylammonium) pentacyanoperoxynitritocobaltate(III) (1). This novel complex is…
Thin films of polymer blends are molded into strips for investigating the influence of lateral confinement on phase separation. The strip has a width and thickness of 17 μm and 1.0 μm, respectively, and contains a 50/50 blend of poly(methyl methacrylate) (PMMA) and poly(styrene- ran -acrylonitrile) (SAN). Upon anneali…
A series of novel spironaphthoxazine-containing rhenium(I) tricarbonyl diimine complexes, which show interesting photoluminescence behavior involving intramolecular photosensitization, have been synthesized and their photochromic properties studied.
We report herein two new nonlinear optical (NLO) crystals, [Et4N][Cd(XCN)3], where X = S (1) and Se (2), that are transparent from 220 to 3300 nm, covering the entire near-ultraviolet, the visible, and the near-infrared spectral regions and giving rise to a very wide and continuous optical window, which is useful for…
Unusually large spontaneous and piezoelectric fields in the III-V nitrides have led to the making of an entirely new class of two-dimensional electron gas. Fluctuation from a perfectly periodic binary structure in highly polar semiconductor alloys present the same physical situation as a random distribution of microsc…
DFT schemes based on conventional exchange-correlation (XC) functionals have been employed to determine the dipole moment (μ), polarizability (α), and first (β) and second (γ) hyperpolarizabilities of push−pull π-conjugated systems. In addition to the failures already pointed out for α and γ in a recent study on polya…
Tetrachlorophthalic anhydride (1) was reacted with L-leucine (2) in toluene solution at refluxing temperature in the presence of triethylamine and the resulting imide-acid (4) was obtained in quantitative yield. The compound (4) was converted to the N-(tetrachlorophthaloyl)-L-leucine acid chloride (5) by reaction with…
The procedure of five consecutive recycling steps by injection moulding of postconsumer PET was evaluated on the basis of processing and drying parameters. The equations that govern the increase in sample mass of the polymer while in contact with the atmosphere were obtained on the basis of weight variation measuremen…
The imidization and phenylethynyl end-group reaction behavior of phenylethynyl-terminated imide oligomers (LaRC™ PETI-5) with a number-average molecular weight of 2500 g/mol has been extensively interpreted in terms of the disappearance and appearance of several characteristic absorption peaks. Most characteristic FTI…
The influence of the chemical structures of the polyamides on chlorine resistance was studied by measuring their chlorine uptake rates. They were prepared from isophthaloyl dichloride and aliphatic, cycloaliphatic, or aromatic diamines by the solution or interfacial polycondensation method. This study showed that the…