Materials Literature
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Assembly reactions that can prepare reliably regioselective metallamacrocyclic complexes have been a target in the development of metallacrowns. To this end, a series of mixed ligand and mixed ligand/mixed metal metallacrowns have been synthesized in high yield and structurally characterized. Two distinct connectiviti…
A new aqueous solution based approach has been proposed to prepare transition metal dichalcogenides by hydrothermal reaction between aqueous transition metal salts and Na 2 S 2 O 3 or Na 2 SeSO 3 at the low temperature of 130−140 °C. Pyrite NiS 2, CoS 2, FeS 2, and NiSe 2 and layered MoS 2 and MoSe 2 have been prepare…
Quantum and thermal behaviors of low-dimensional mixed-spin systems are investigated with particular emphasis on the design of molecule-based ferromagnets. One can obtain a molecular ferromagnet by assembling molecular bricks so as to construct a low-dimensional system with a magnetic ground state and then coupling th…
We have investigated the role of localized {\it d} bands in the dynamical response of Au, on the basis of {\it ab initio} pseudopotential calculations. The density-response function has been evaluated in the random-phase approximation. For small momenta, we have found a double peak structure in the energy-loss functio…
Iron oxide-based porous solids were prepared by a sol−gel process using Fe(III) salts in various solvents. It was observed that the addition of propylene oxide to Fe(III) solutions resulted in the formation of transparent red-brown monolithic gels. The resulting gels were converted to either xerogels by atmospheric dr…
Nanostructured materials may be defined as those materials whose structural elements - clusters, crystallites or molecules - have dimensions in the 1 to 100 nm range. The explosion in both academic and industrial interest in these materials over the past decade arises from the remarkable variations in fundamental elec…
Polarization dependent photoluminescence (PL), time-resolved PL and PL excitation experiments are performed in order to clarify the origin of the linear polarization of the PL of porous Silicon excited by linear polarized light. It is shown that this effect, when PL is excited significantly above the detection energy,…
Numerical simulation of the phase separation kinetics in ternary mixtures with different interfacial properties is performed by means of the cell dynamics approach. We discuss the effects of the competition between the phase separation and the wetting phenomena on the system morphology and growth dynamics. Morphologic…
The model system of parallel hard cubes is studied by using fundamental measure theory (FMT) and extensive Monte Carlo simulations. A continuous freezing transition occurs in this system to which finite-size scaling analysis is applied. Significant deviations from a previous simulation study are found for the position…
The effect of external (magnetic or electric) fields on the swelling of nematic gels dissolved in an isotropic solvent are discussed. We calculate the swelling ratio of the gel, orientational order parameter, and phase diagrams on a temperature–swelling ratio plane under an external field. For a weak external field, w…
The x-ray storage phosphor properties of fluorozirconate glasses doped with Eu 2+ and Br - were interpreted previously to be due to BaBr 2 :Eu 2+ crystalline precipitates. In order to compare their behaviour with BaBr 2 :Eu 2+ single crystals, we grew such single crystals and investigated them with electron paramagnet…
Cycloheptanol, cyclo-octanol, cyanoadamantane and cis-1,2-dimethylcyclohexane are known to form plastic crystals which can be supercooled to show a glass transition at a temperature Tg. The molecular dynamics in different plastic phases is studied in their supercooled states using dielectric spectroscopy (frequency ra…
Boehmite and pseudoboehmite were studied in order to find the effect of their individual properties upon the properties of transitional alumina and α-Al 2 O 3 produced thereof; the influence of steaming on these properties was also considered. Samples were characterized by X-ray powder diffraction, crystalline structu…
NAD+-dependent formate dehydrogenase (FDH) from Candida boidinii was cloned and expressed to a high level in Escherichia coli (20% of soluble E. coli protein). Molecular modelling studies were used to create a three-dimensional model of C. boidinii FDH, based on a known structure of the Pseudomonas sp. 101 enzyme. Thi…
The substitution of rare-earth ions into insulating host crystals introduces lattice strains and, for non-trivalent sites, a need for charge compensation. Such effects alter the site symmetry and this is reflected in properties such as the wavelength, linewidth, lifetime and relative intensity of the rare-earth transi…
We present a theoretical methodology to study the electronic response properties of a chromophore physisorbed on a metal particle. In particular the chromophore is treated at ab initio level whereas the metal particle is described through its dielectric properties. The use of a boundary elements method for the resolut…
New high surface area carbon materials were prepared at low temperature (600 °C) using zeolite (Y, Beta, and ZSM-5) and montmorillonite clay (K10) templates. Acrylonitrile, furfuryl alcohol, pyrene, and vinyl acetate precursors were polymerized and carbonized in each of the inorganic matrixes without the addition of a…
Dioxygen accelerates back electron transfer (BET) processes between a fullerene radical anion (C60) and a radical cation of zinc porphyrin (ZnP) in photolytically generated ZnP.+-C60.- and ZnP.+-H2P-C60.- radical ion pairs. The rate constant of BET increases linearly with increasing oxygen concentration without, howev…
Figure 1 shows a representative set of ISF’s, made at \nwave vectors below, near, and above the position qm of \nthe main peak in S(q). Increasing the concentration \nfrom freezing (ø /—0.494) to φ "0.574 lengthens the \noverall decay time of f ( q y r ) by nearly four decades, from \nabout 10s to 109 /is, and signifi…
The fundamental question of how chirality affects the electronic coupling of a nanotube to metal contacts is important for the application of nanotubes as nanowires. We show that metallic-zigzag nanotubes are superior to armchair nanotubes as nanowires, by modeling the metal-nanotube interface. More specifically, we s…