Materials Literature
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The effect of an oriented microphase-separated structure, induced by an applied flow bias field (roll casting), on the crystallization of the polyethylene (PE) block in a semicrystalline polystyrene- block -(polyethylene- alt -propylene)- block -polyethylene terpolymer has been analyzed. The orientation and morphology…
Calculations of crystal field parameters from first principles depend upon a knowledge of the crystal structure in the immediate neighbourhood of the magnetic ion. The calculated crystal field contributions for single ligands (see Chapter 1) can then be combined to estimate values of the crystal field parameters for r…
Batch adsorption experiments in the presence of oxygen were performed to study the interlayer reactions of aniline on Cu(II)-montmorillonite in aqueous solutions. At concentrations below a critical value of C C = 2.6 mmol dm - 3 only a colored Cu(II)−aniline complex is formed, characterized by a stability constant of…
The reaction mechanism and energetics for the conversion of methanol to formaldehyde by an iron−oxo species, FeO +, is investigated. Three competitive reaction pathways for the catalytic reaction are analyzed from DFT computations at the B3LYP level of theory. In Path 1, the H atom of the OH group of methanol is first…
Amine-based donor radicals, such as dimethylamino-, diethylamino- and morpholinonitronyl nitroxides, were synthesized, and their donor abilities were examined by cyclic voltammetry. ESR spectra of the singly oxidized donor radicals showed ground state triplet signals derived from the cation radicals of these donor rad…
Hexanuclear {[Mn(bpy)2]2(μ-NC)2[Mo(CN)6]2(μ-CN)2[Mn(bpy)2]2}· 8H2O is formed in the reaction of the [Mo(CN)8]4- complex with labile cis-[Mn(bpy)2Cl2] in aqueous solution. The X-ray structure of the Mn4Mo2 cluster reveals an octahedral geometry with Mn atoms in a rectangular array. The Mo units located on the axis almo…
Reaction of magnesium sulfate with aqueous ammonia in a hydrothermal condition (150−180 °C) produced a fibrous magnesium hydroxide sulfate hydrate (MHSH) with a composition corresponding to a stoichiometry of 4.34Mg(OH) 2 ·MgSO 4 · x H 2 O. Chemical composition analysis showed that the quantity of x was more likely to…
We report the synthesis of nonaqueous dispersion of CdSe nanoparticles and the layer-by-layer assembly of hybrid poly(vinylpyridine) (PVP)/CdSe multilayer thin films based on hydrogen bonding. The multilayer buildup is monitored by UV−vis spectra, which showed a linear increase of the film absorbance with the number o…
Electrochemically prepared poly(3,4-dimethoxypyrrole), poly(3,4-dimethoxythiophene), poly(3,4-ethylenedioxypyrrole), and poly(3,4-ethylenedioxythiophene) have been characterized by cyclic voltammetry (CV) and ultraviolet−visible (UV−vis) and Fourier transform infrared (FTIR) spectroscopy and were subsequently investig…
Enzymatic phosphorylation and dephosphorylation reactions were used to modify a genetically engineered variant of spider dragline silk. The approximately 25 kDa protein was phosphorylated with cyclic AMP-dependent kinase and dephosphorylated with calf intestinal alkaline phosphatase. Phosphorylation inhibited beta-she…
A new strategy for synthesis of hyperbranched polymers from commercially available A 2 type and BB‘ 2 type monomers has been developed. In the first part of this series, hyperbranched polysulfone−amine with multiamino groups is prepared by polyaddition of 1-(2-aminoethyl)piperazine (BB‘ 2 ) to divinyl sulfone (A 2 ) w…
We investigate the effects of impurity scattering on the conductance of metallic carbon nanotubes as a function of the relative separation of the impurities. First we compute the conductance of a clean (6,6) tube, and the effect of model gold contacts on this conductance. Then, we compute the effect of introducing a s…
133Cs and 13C-NMR have been used to study the electronic properties of the polymerized phase of CsC60 at ambient and under hydrostatic pressure. The salient result of this study is the finding of fluctuations in the local field at 133Cs site which are independent of the applied pressure and due to thermally activated…
The solution structure and dynamics of metal-bound water exchange have been studied in a series of diastereoisomeric gadolinium complexes of tetra(carboxyethyl) derivatives of 1,4,7,10-tetraazacyclodecane. The structures of the ( RRRS ), ( RSRS ), and ( RRSS ) ligands and the Eu, Gd, and Tb complexes of the ( RRRR ) i…
Core/shell semiconductor nanocrystals with InAs cores were synthesized and characterized. III−V semiconductor shells (InP and GaAs), and II−VI semiconductor shells (CdSe, ZnSe, and ZnS) were overgrown on InAs cores with various radii using a two step synthesis. In the first step cores were prepared, and in the second…
A procedure of the template displacement by organosilanes was utilized to prepare pure-silica and cerium-substituted mesoporous materials with tailored surface functionality. These two self-assembled mesostructured systems exhibit hexagonal arrangement of mesopores but they show different reactivity with respect to or…
The complex {Fe[HC(3,5-Me2pz)3]2}(BF4)2, shown crystallographically to contain a unique octahedral N6Fe site, shows a new type of spin-crossover behavior. The solid is high-spin from 350 K down to a temperature of 206 K, but below 206 K it undergoes a very abrupt decrease in magnetic moment. Mössbauer studies show con…
Depending on the experimental conditions, various charged water soluble porphyrins can aggregate, leading to large supramolecular assemblies whose basic building blocks are constituted by J-type aggregates or heteroaggregated species made up by oppositely charged molecules. The mesoscopic structures resulting on (i) t…
We electrochemically synthesized film -type vanadium hexacyanochromate-based magnets with high critical temperatures ( T c ): K I 0.31 V II 0.49 V III 0.51 [Cr III (CN) 6 ] 0.94 ·6.5H 2 O ( 1 ) ( T c = 310 K) and K I 0.61 V II 0.97 V III 0.03 [Cr III (CN) 6 ] 0.88 ·7.2H 2 O·0.4C 2 H 5 OH ( 2 ) ( T c = 345 K). The colo…
Tm(3+)-doped tellurite glass is investigated as a host for a broadband amplifier at 1.47 mum. The Tm(3+) fluorescence spectrum, lifetime, and cross section in tellurite glass are compared with those in fluorozirconate glasses. The advantages of a Tm(3+)-tellurite amplifier, especially when it is employed in combinatio…