Preparation of a Pt–Ru bimetallic system supported on carbon nanotubes
Pt–Ru nanoparticles (1.6 nm) were supported on carbon nanotubes (200 nm diameter, 8–10 µm length) obtained by the carbonisation of polypyrrole on an alumina membrane.
Materials Literature
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Preparation and Characterization of Spray-Dried Polymeric Nanocapsules
Recently, much interest has been generated by colloidal drug delivery systems such as nanocapsules because of the possibilities for controlled release, increased drug efficacy, and reduced toxicity after parenteral administration. Nanocapsules of poly-epsilon-caprolactone and Eudragit S90 were prepared. However, these…
Structure and magnetic properties of two cyanide-bridged one-dimensional M–CuII (M = FeIII or FeII) bimetallic assemblies from ferricyanide and CuN42+ (N4 = 1,4,8,11-tetraazacyclotetradecane and N,N ′-bis(2-pyridylmethylene)-1,3-propanediamine) building blocks
Two bimetallic assemblies K[Cu(cyclam)][Fe(CN)6]·4H2O 1 and [Cu(L)][Cu(L1)][Fe(CN)6]·6.5H2O 2 (cyclam = 1,4,8,11-tetraazacyclotetradecane; L = N,N′-bis(2-pyridylmethylene)-1,3-propanediamine and L1 = N-2-pyridylmethylene-1,3-propanediamine) have been prepared from the reaction of [Fe(CN)6]3− and the precursors [Cu(cyc…
Template synthesis of polymer-insulated colloidal gold nanowires with reactive ends
Alternate adsorption of anionic and cationic polyelectrolytes creates smooth organic films on the walls of template-grown Au nanowires, which can be made chemically reactive on their ends by removal of a sacrificial Ag layer.
Second-generation fluorous chiral (salen) manganese complexes
Sterically hindered chiral (salen)manganese complexes bearing long perfluoroalkyl substituents are synthesized and successfully employed as catalysts in the enantioselective (ee = 50–87%) epoxidation of alkenes under fluorous biphasic conditions.
The Rayleigh-like collapse of a conical bubble
Key to the dynamics of the type of bubble collapse which is associated with such phenomena as sonoluminescence and the emission of strong rebound pressures into the liquid is the role of the liquid inertia. Following the initial formulation of the collapse of an empty spherical cavity, such collapses have been termed…
Synthesis of optically active poly(amide-imide)s derived fromN,N?-(4,4?-carbonyldiphthaloyl)-bis-L-leucine diacid chloride and aromatic diamines by microwave radiation
3,3′,4,4′-benzophenonetetracarboxylic dianhydride (4,4′-carbonyldiphathalic anhydride) was reacted with L-leucine in a mixture of acetic acid and pyridine (3 : 2), and the resulting imide-acid [N,N′-(4,4′-carbonyldiphthaloyl)-bis-L-leucine diacid] was obtained in quantitative yield. The compound was converted to the N…
Solid state coordination chemistry of oxovanadium phosphates: hydrothermal syntheses and structures of the network and chain phosphate phases [{Cu(bpy)}2(VO)3(PO4)2(HPO4)2]·2H2O and [{Cu(terpy)}2(VO2)3(PO4)(HPO4)2]
The hydrothermal reactions of Cu2O, the appropriate polypyridine ligand, Na3VO4, H3PO4 and H2O at 200 °C yield the two-dimensional material [{Cu(bpy)}2(VO)3- (PO4)2(HPO4)2]·2H2 O and the one-dimensional phosphate [{Cu(terpy)}2(VO2)3(PO4 )(HPO4)2], examples of the structure-directing role of secondary metal–ligand subu…
Electronic structure ofLaMnO3in theab initiocrystal Hartree-Fock approximation
We find that an ab initio electronic structure calculation in the Hartree-Fock approximation (HFA) leads to the experimentally observed magnetic and orbital orderings in ${\mathrm{LaMnO}}_{3},$ as well as its insulating character. While such agreement was also found in density-functional theories (DFT's), there are la…
Structure and magnetic properties of a nickel(ii) complex of a tridentate verdazyl radical: strong ferromagnetic metal-radical exchange coupling
Magnetic susceptibility measurements on a structurally characterized nickel(II) complex of a tridentate verdazyl radical indicate very strong ferromagnetic Ni–verdazyl intramolecular exchange interactions (J > +200 cm−1).
Decoupling of the magnetic ordering of the rare-earth and the Co sublattice inEr1−xYxCo2compounds driven by substitution or pressure
The thermodynamic and transport properties of the ${\mathrm{Er}}_{1\ensuremath{-}x}{\mathrm{Y}}_{x}{\mathrm{Co}}_{2}$ system were studied in the concentration range $0.0<~x<~1.0.$ In this system, the first-order magnetic phase transition observed in ${\mathrm{ErCo}}_{2}$ at ${T}_{\mathrm{C}}=32$ K is related to…
Serine Acetyltransferase from Escherichia coli Is a Dimer of Trimers
Equilibrium sedimentation studies show that the serine acetyltransferase (SAT) of Escherichia coli is a hexamer. The results of velocity sedimentation and quasi-elastic light scattering experiments suggest that the identical subunits are loosely packed and/or arranged in an ellipsoidal fashion. Chemical cross-linking…
Thermotropic liquid-crystalline folic acid derivatives: supramolecular discotic and smectic aggregation
Thermotropic discotic and smectic liquid crystallinity can be induced for folic acid derivatives having octadecyl and undecyl substituents in wide temperatures ranges, respectively; the addition of sodium triflate to smectic liquid-crystalline folic acid leads to a change of the assembled structures from smectic to co…
Effect of high-pressure processing on the permeance of selected high-barrier laminated films
This study investigated the effects of high pressure processing (HPP) on the barrier properties of eight multilayer films. Pouches made from these films were filled with distilled water, sealed and then pressure processed at 600 and 800 MPa for 5, 10 and 20 min at 45°C. Controls were similarly prepared but exposed to…
A novel hybrid layer compound containing silver sheets and an organic spacer
A novel compound of the formula Ag2·CA (CA = cyanuric acid) possessing Ag sheets and hydrogen-bonded CA chains, exhibits anisotropic conductivity and acts as an infinite parallel plate capacitor with a high dielectric constant.
Formation of an Iron-Oxo Species upon Decomposition of Dinitrogen Oxide on a Model of Fe-ZSM-5 Zeolite
Abstract The so-called ``α-oxygen" on Fe-ZSM-5 zeolite, a surface oxygen species responsible for high reactivity in oxidation of methane and of benzene, has been investigated. We present from density-functional-theory (DFT) calculations how such a reactive surface species is generated upon decomposition of dinitrogen…
Surface immobilization of poly(ethylene oxide): Structure and properties
We covalently immobilized poly(ethylene oxide) (PEO) chains onto a fluorinated ethylene propylene copolymer (FEP) surface. On the FEP surface, aldehyde groups were first deposited by plasma polymerization of acetaldehyde or acrolein. Then, amino-PEO chains were immobilized through Schiff base formation, which was foll…
Reversible thermal behavior of the layered double hydroxide of Mg with Al: mechanistic studies
The layered double hydroxide (LDH) of Mg with Al decomposes at 450 °C to yield a mixed metal oxide. The oxide reconstructs back to the parent LDH either on cooling in air or soaking in water. This reversible thermal behaviour was attributed to the formation of an unstable defect rocksalt phase (comprising Al3+ ions pa…
A novel preparation of polyimide/clay hybrid films with low coefficient of thermal expansion
A novel polyimide (PI)/clay hybrid nanocomposite, designated as PI (PAAS)/CM, has been developed from the poly(amic acid) salt of triethylamine and organomontmorillonite (CM) using a mixture solution of tetrahydrofuran (THF) and methanol (MeOH). For comparison, two other PI/clay hybrids derived from poly(amic acid) an…
Water-dispersible nanocomposites of polyaniline and montmorillonite
The polymerization of aniline (ANI) in aqueous medium in the presence of (NH4)2S2O8 and montmorillonite (MMT) resulted in the formation of a nanocomposite (PANI–MMT). The inclusion of PANI in the composite was confirmed by FTIR studies. The extent of PANI loading in the composite increased with ANI concentration at a…