Materials Literature
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The catalytic reaction between adsorbed oxygen atoms and CO molecules on Pt(111) was investigated by scanning tunneling microscopy and modeled by Monte Carlo simulations. Experiments were performed by dosing preadsorbed Oad layers with CO between 237 and 274 K. Two stages were observed during dosing with CO, an initia…
The mononuclear gadolinium mixed-ligand complex [Gd(CF3CO2)3(phen)2(H2O)] has been prepared and structurally characterized by X-ray crystallography. Two complex molecules are doubly bridged by H bonds between carboxylate and aqua ligands with a Gd−Gd separation of 7.16(1) Å. Magnetic susceptibility and EPR measurement…
Isolation of the free bicyclic tetraamine, [3(5)]adamanzane.H(2)O (1,5,9,13-tetraazabicyclo[7.7.3]nonadecane.H(2)O), is reported along with the synthesis and characterization of a copper(II) complex of the smaller macrocycle [(2.3)(2).2(1)]adamanzane (1,5,9,12-tetraazabicyclo[7.5.2]hexadecane) and of three cobalt(II),…
Surface bound chitosan−sialodendrimers with a high degree of substitution were successfully prepared using a doubly convergent approach. Poly(amidoamine) (PAMAM) dendrimers ( G = 1−5) having a 1,4-diaminobutane core were amidated to N -carboxyethylchitosan methyl ester under conditions that prevented cross-linking. Th…
The first photosensitive liquid crystalline (LC) dendrimer with terminal cinnamoyl groups was synthesized. A new approach to the synthesis of photochromic carbosilane LC dendrimers was elaborated. The method consists of synthesis of dendrimer with terminal hydroxyl groups and then coupling of 4-methoxycinnamoyl chlori…
Unionid shells are characterized by an outer aragonitic prismatic layer and an inner nacreous layer. The prisms of the outer shell layer are composed of single-crystal fibres radiating from spheruliths. During prism development, fibres progressively recline to the growth front. There is competition between prisms, lea…
Simulations have been performed at 473 K for one-component melts of polyethylene (PE) and head-to-head, tail-to-tail polypropylene (hhPP) as well as a mixture of the two species. The densities are 0.760, 0.753, and 0.756 g/cm 3 for these three NVT simulations, respectively. The Monte Carlo simulation uses coarse-grain…
The 23 Na and 29 Si NMR spectra of the sodium−silicon clathrate materials Na 8 Si 46 and Na x Si 136 (1 < x < 24) and the parent Zintl phase NaSi have been studied in detail with a view to ironing out a number of ambiguities in the published literature and to determining properties of these potential thermoelectric ma…
Copper(II) azide complexes of three tridentate ligands namely 2,6-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L), 2,6-(pyrazol-1-ylmethyl)pyridine (L'), and dipropylenetriamine (dpt) yield three kinds of complexes with different azide-binding modes. The ligand L forms two end-on-end (mu-1,3) diazido-bridged binuclear co…
A theoretical and computational study of the nitrogen superhyperfine structure in Cu(II) complexes is reported. The determination of hybridization parameters for nitrogen donor orbitals from the data is examined. For most Cu(II) complexes the results deviate substantially from pure “sp 2 ” or “sp 3 ” hybridization. Se…
The combination of small-angle X-ray scattering and qualitative porosimetry is applied to the puzzling phenomenon of overly large specific surface areas in some mesoporous silicas. Geometrical calculations, considering the relationship between structure, lattice parameter, and specific surface area, reveal the latter…
The homoleptic complexes [Ph(4)P](2)[Co[N(CN)(2)](4)] and [Ph(4)P][M[N(CN)(2)](3)] [M = Co, Mn] have been structurally as well as magnetically characterized. The complexes containing [M[N(CN)(2)](4)](2-) form 1-D chains, which are bridged via a common dicyanamide ligand in [M[N(CN)(2)](3)](-) to form a 2-D structure.…
Manganese oxide catalysts supported on Al 2 O 3, ZrO 2, TiO 2, and SiO 2 supports were used to study the effect of support on ozone decomposition kinetics. In-situ laser Raman spectroscopy, temperature-programmed oxygen desorption, surface area measurements, and extended and near-edge X-ray absorption fine structure (…
The synthesis of silver and gold metal nanospherical particles stabilized by the fourth-generation poly(amido amine) (G4 PAMAM) dendrimer is reported. The reduction of silver nitrate and sodium tetrachloroaurate in the presence of the PAMAM dendrimer having terminal amine groups results in the formation of stable, wat…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHydroxylated Quantum Dots as Luminescent Probes for in Situ HybridizationSrikant Pathak, Soo-Kyung Choi, Norman Arnheim, and Mark E. ThompsonView Author Information Department of Chemistry and Molecular Biology Program University of Southern California Los Angeles, Cal…
The refractive index is a measure of how much light slows down when it enters a medium. Conventional materials have a positive refractive index that is normally greater than 1. In his Perspective, Wiltshire explains how Shelby et al. were able to defy convention and make a negative refractive index material without vi…
Recently, a variety of aliphatic polyesters have been synthesized using hydrolases such as lipases and PHB depolymerases, and the reaction mechanism for these enzyme-catalyzed polymerization has been discussed. In this paper, we have studied the involvement of the catalytic amino acid residues of the hydrolase in enzy…
The thermal decomposition of hydrotalcite-like materials containing Zn(II), Fe(III), and Al(III) is studied. One of these samples contains zinc and aluminum in the brucite-like layers, while iron is incorporated as hexacyanoferrate(III) anions in the interlayer space. A second set of samples with Fe/Al atomic ratios i…
Theoretical calculations of 17 O and 14 N nuclear quadrupole coupling (NQC) constants (χ) and asymmetry parameters (η) for small α-helix and β-sheet protein fragments have been carried out using the density functional theory. This computational study is intended to shed light on the differences between the two major s…
We report on the transport properties, Hall effect and resistivity, of epitaxial ${\mathrm{La}}_{1\ensuremath{-}y}{\mathrm{TiO}}_{3+\ensuremath{\delta}}$ thin films. The materials, grown by molecular beam epitaxy, display a temperature independent Hall coefficient and a characteristic ${T}^{2}$ dependence of the resis…