Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTRedox Behavior of Polyaniline−Transition Metal Complexes in SolutionMasayoshi Higuchi, Daisuke Imoda, and Toshikazu HiraoView Author Information Department of Applied Chemistry, Faculty of Engineering, Osaka University, Yamada-oka,…
We use atomic force microscopy (AFM) with phase detection imaging (PDI) in order to study the surface microdomain morphology of thick (i.e., ca. 2 mm) films of triblock copolymers. We present here the results obtained on a poly(methyl methacrylate)- block -polybutadiene- block -poly(methyl methacrylate) (PMMA- b -PBD-…
Nickel-containing mesoporous materials MCM-41 and AlMCM-41 have been prepared by synthesis and ion exchange. These materials are catalytically active for ethylene dimerization and 1-butene isomerization. The catalytic activity for the dimerization reaction is shown to be due to nickel(I) species, while the 1-butene di…
Carbon spheres have been synthesized using a mixed-valent oxide-catalytic carbonization process in macroscopic quantities and at low cost. The technique uses natural gas and reusable catalysts and produces no environmental waste or pollution. The product is all solid spheres (∼210 nm) comprised of layered graphitic fl…
We show how to measure dynamic specific heat and thermal conductivity of a solid or liquid sample using the 3ω technique, which is an ac-modulation method where we use a heater simultaneously as the sensor. By varying the width of the heater relative to the thermal decay length, one can choose the proper regime to mea…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTTheoretical and Experimental Evidence for SN2 Transition States in Oxidative Addition of Methyl Iodide to cis-[M(CO)2I2]- (M = Rh, Ir)Tim R. Griffin, David B. Cook, Anthony Haynes, Jean M. Pearson, Donato Monti, and George E. MorrisView Author Information Department of…
The study of very low temperature magnetic relaxation in nanostructured materials has provided the opportunity to observe the occurrence of quantum tunneling of magnetization (QTM) in many different systems. As the magnetization is a classical vector, this effect is also referred to as macroscopic quantum tunneling (M…
The morphological behavior of a series of well-defined A 2 B simple graft or “Y” architecture block copolymers is characterized via small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). This model architecture is formed by grafting a polystyrene block onto the center of a polyisoprene backbon…
The surface-enhanced Raman scattering (SERS) spectra of pyridine have been analyzed on the basis of a resonant charge transfer (CT) mechanism. The most intense bands recorded in the SERS at negative electrode potentials correspond with the normal modes that connect the equilibrium geometries of the neutral molecule an…
KBi 6.33 S 10 and K 2 Bi 8 S 13 were synthesized by the direct combination of K 2 S/Bi 2 S 3 at high temperature (>700 °C). The reaction of K 2 S/3.3Bi 2 S 3 at 800 °C revealed the presence of a new ternary sulfide KBi 6.33 S 10 ( I, 92% yield). The shiny, silver polycrystalline material crystallizes in the orthorhomb…
Crystalline, thermostable molecular sieve MCM-41 with hexagonal channel porosity is synthesized in a temperature-controlled microwave oven from aged precursor gels within about one hour.
A stochastic simulation method employing suitable experimentally based cross sections has been developed for probing the spatial distribution of energy loss and the trajectory of 100 eV to 1 MeV electrons in gaseous and liquid water. Elastic collisions and large-energy-loss inelastic collisions strongly influence the…
The equilibrium mixture of yeast enolase with substrate, 2-phospho-D-glycerate (2-PGA), and product, phosphoenolpyruvate (P-enolpyruvate), has been crystallized from solutions of poly(ethylene glycol) (PEG) at pH 8.0. Crystals belong to the space group C2 and have unit cell dimensions a = 121.9 A, b = 73.2 A, c = 93.9…
The peroxides from methylrhenium trioxide (MTO) and hydrogen peroxide, CH 3 ReO 2 (η 2 -O 2 ), A, and CH 3 Re(O)(η 2 -O 2 ) 2 (H 2 O), B, have been fully characterized in both organic and aqueous media by spectroscopic means (NMR and UV−vis). In aqueous solution, the equilibrium constants for their formation are K 1 =…
The synthesis of 2(3),9(10),16(17),23(24)-tetrasubstituted phthalocyanines from 1,2-dicyano-4-alkoxybenzenes or the corresponding isoindolines is reported. In each case, four isomers with D 2 h, C 4 h, C 2 v, and C s symmetry are obtained in the statistical expected yield. The separation of the C 4 h and the D 2 h iso…
A fluorescent polymer of 2-naphthol is prepared using the oxidative enzyme horseradish peroxidase encapsulated in the microstructured system of AOT/isooctane reversed micelles. The monomer, being amphiphilic, partitions to the oil−water interface with the hydroxyl moieties directed toward the microaqueous core. The en…
A model of packing for the ordered modification of the α form of syndiotactic polystyrene is suggested, through comparisons between calculated structure factors and experimental intensities observed in the X-ray fiber and electron diffraction patterns. The present analysis improves the preliminary model proposed in pr…
We have explored the use of chain end segregation as a means of controlling the properties of a polymer surface. Thin film blends of homopolystyrene (PS) and PS synthesized with low-energy oligotetrafluoroethylene chain ends (PS-TFE) were studied using neutron reflectivity. The fraction of PS-TFE that localizes near t…
The reaction of Mn(O(2)CPh)(2).2H(2)O and PhCO(2)H in EtOH/MeCN with NBu(n)(4)MnO(4) gives (NBu(n)(4))[Mn(4)O(2)(O(2)CPh)(9)(H(2)O)] (4) in high yield (85-95%). Complex 4 crystallizes in monoclinic space group P2(1)/c with the following unit cell parameters at -129 degrees C: a = 17.394(3) Å, b = 19.040(3) Å, c = 25.6…
UDP-galactose 4-epimerase catalyzes the conversion of UDP-galactose to UDP-glucose through a mechanism involving the transient reduction of NAD+. Here we describe the X-ray structures for epimerase complexed with NADH/UDP, and NAD+/UDP, refined to 1.8 and 2.0 angstrom, respectively. The alpha-carbon positions for the…