Materials Literature
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The methyltrioxorhenium(MTO)-catalyzed oxidation of silanes to silanols and the epoxidation of various olefins by aqueous 85% H(2)O(2) proceed in high yields and excellent product selectivities (no disiloxanes, diols) in the presence of the zeolite NaY. The oxidative species is located inside the 12-A supercages. This…
The synthesis and characterization of iron-containing MCM-41 porous silica using the exchange method of the template with the iron salts FeCl 3 ·6H 2 O and (Fe 3 Ac 6 O·3H 2 O)NO 3 is reported. Proper conditions under which the exchange reactions can be accomplished without destroying the lattice structure of the pare…
The synthesis and electrochemistry of a series of tetrathiafulvalene (TTF) and dithia-crown-TTF derivatives attached with one or two disulfide group(s) 7a-f are reported. The self-assembled monolayers (SAMs) of these TTF disulfides on gold were prepared and characterized by reflection-absorption infrared spectroscopy.…
In this work we have determined, on a series of 0.5% Pd/C catalysts, the palladium particle sizes by the following physical techniques: (i) X-ray diffraction (XRD) line broadening (LB) method, associated with the Rietveld method, (ii) small-angle X-ray scattering, and (iii) transmission electron microscopy. The cataly…
We have utilized X-ray absorption fine structure (XAFS) spectroscopy to investigate the local atomic and electronic structure of iron incorporated into electrodeposited nickel hydroxide films. We found that cathodic codeposition from a solution containing Fe(II) and Ni(II) ions results in iron occupying Ni lattice sit…
Brownian dynamics simulations of perfect dendrimers up to the sixth generation have been performed under the influence of simple shear flow. Hydrodynamic and excluded volume interactions have been taken into account explicitly. The onset of shear-thinning is observed to occur at lower shear rates for larger dendrimers…
We study the dynamics of the glass formers toluene and glycerol below the glass transition temperature T g by means of 2 H NMR techniques. Whereas for toluene a slow β-process is observed in dielectric spectroscopy, this process is not discernible in glycerol. We demonstrate that standard 1D and 2D NMR experiments can…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTLight-Scattering Study of a Zwitterionic Polycarboxybetaine in Aqueous SolutionAizhen Niu, Der-Jang Liaw, Hui-Chuan Sang, and Chi WuView Author Information Department of Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong; Department of Chemical Engineering…
The chemisorption properties of NO on the oxidized TiO 2 (110) surface have been investigated using both experimental and theoretical methods. The results of temperature-programmed desorption measurements indicate that for NO exposures less than 1.1 × 10 14 molecules/cm 2 NO adsorbs weakly and desorbs at ∼127 K. The t…
An analysis of the cylindical brush of an isolated comb copolymer molecule consisting of a semiflexible backbone and flexible side chains is presented. Using the Alexander−de Gennes approximation, we calculate the free energy of both straight and bent cylindrical brush and the brush persistence length λ, and show that…
A range of sodium caseinate samples were characterized by a multiangle laser light scattering (MALLS) system or by the use of MALLS as an on-line detector with size-exclusion chromatography (SEC). Sodium caseinate solutions, analyzed using a MALLS system alone, gave weight-average molar mass (M(w)) values in the range…
A carotenoid (C) porphyrin (P) fullerene (C 60 ) molecular triad (C−P−C 60 ) has been synthesized and found to undergo photoinduced electron transfer from the porphyrin first excited singlet state or to the fullerene first excited singlet state to yield C−P •+ −C 60 •- . Electron transfer from the carotenoid then give…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDesign and Structural Analysis of the First Spherical Monodendron Self-Organizable in a Cubic LatticeVirgil Percec, Wook-Dong Cho, Martin Möller, Svetlana A. Prokhorova, Goran Ungar, and Duncan J. P. YeardleyView Author Information Roy & Diana Vagelos Laboratories Depa…
We examine thin films of two simple metals (aluminum and lithium) in the stabilized jellium model, a modification of the regular jellium model in which a constant potential is added inside the metal to stabilize the system for a given background density. We investigate quantum-size effects on the surface energy and th…
Two erbium doped germanate glass samples prepared by sol-gel process and melting and casting method, respectively, have been characterized. A fluorescence lifetime of 2.5 ms at the 4I13/2 level and a very broad bandwidth (FWHM: 53.7 nm) around 1.55 micrometers have been observed for the sol-gel sample. The fluorescenc…
For the first time, an observation of second-order nonlinear susceptibility in an As2S3 chalcogenide glass thin film is reported. Both thermal poling and optical poling were used to induce this nonlinearity. In both cases, the magnitude of the χ333 coefficient was estimated to be > 0.6 pm/V.
Algorithms and experimental techniques for extracting the complex dielectric function of thin films (monolayers and bilayers) of quantum dots are developed. The algorithms are based on a combination of the so-called Newton−Raphson method, used in conjunction with a Kramers−Kronig analysis, and are used to analyze norm…
Unsaturated biopolyesters, (PHA−DB), obtained from pure anchovy (hamci), hazelnut, soybean oily acids and the mixtures of octanoic acid (in weight ratios of 50/50 and 70/30) were chlorinated up to 54 wt % Cl content. The molecular weights (MW) of the chlorinated biopolyesters were between 1.3 × 10 4 and 3.0 × 10 4 and…
The series of mononuclear iron(II) complexes with the tridentate macrocycle Me3tacn have been prepared (Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclonane). A purple, spin-crossover complex [Fe(Me3tacn)(MeCN)3](CF3-SO3)2 (1-OTf) forms in acetonitrile but readily loses MeCN ligands to form a colorless high-spin complex Fe…
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…