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Novel Syntheses of Hexahydro-1H-pyrrolo[1,2-a]imidazoles and Octahydroimidazo[1,2-a]pyridines

Alan R. Katritzky、Guofang Qiu、Hai‐Ying He 等 4 位作者2000-05-12The Journal of Organic Chemistry

1-Phenyl-5-(benzotriazol-1-yl)hexahydro-1H-pyrrolo[1,2-a]ĭmidazole (18) and 1-phenyl-5-benzotriazolyloctahydroimidazo[1,2-a]pyridine (27) were readily prepared from succindialdehyde or glutaraldehyde, benzotriazole, and N-phenylethylenediamine. Synthons 18 and 27 reacted with Grignard reagents, allylsilanes, silyl eth…

Synthesis and Reactions of Organic CompoundsChemical synthesis and pharmacological studiesPolymer Synthesis and Characterization

Theoretical Study of Pu and Cs Incorporation in a Mono-silicate Neodymium Fluoroapatite Ca9Nd(SiO4)(PO4)5F2

Constantin Meis、Julian D. Gale、Laurent Boyer 等 5 位作者2000-05-12The Journal of Physical Chemistry A

In the context of nuclear waste disposal, the possibility of incorporating selectively plutonium and cesium in a mono-silicate neodymium-fluoroapatite Ca 9 Nd(SiO 4 )(PO 4 ) 5 F 2 (britholite) is investigated. For this purpose, a force field for the modeling of fluoroapatite Ca 10 (PO 4 ) 6 F 2 is established based up…

Nuclear Materials and PropertiesRadioactive element chemistry and processingNuclear materials and radiation effects

Infrared to visible up-conversion study for erbium-doped zinc tellurite glasses

Nejeh Jaba、A. Kanoun、H. Mejri 等 6 位作者2000-05-12Journal of Physics Condensed Matter

Optical absorption and photoluminescence properties of Er 3+ -doped 70TeO 2 -30ZnO glass are investigated. Judd-Ofelt intensity parameters of Er 3+ have been determined to calculate the radiative transition probabilities and the radiative lifetimes of excited states. An infrared to visible up-conversion was observed a…

Solid State Laser TechnologiesGlass properties and applicationsLuminescence Properties of Advanced Materials

Modification of the Interlayer Surface of Kaolinite with Methoxy Groups

Yoshihiko Komori、Hiroyuki Enoto、Ryoji Takenawa 等 6 位作者2000-05-12Langmuir

ADVERTISEMENT RETURN TO ISSUEPREVNoteModification of the Interlayer Surface of Kaolinite with Methoxy GroupsYoshihiko Komori, Hiroyuki Enoto, Ryoji Takenawa, Shigenobu Hayashi, Yoshiyuki Sugahara, and Kazuyuki KurodaView Author Information Department of Applied Chemistry, School of Science and Engineering, Waseda Univ…

CO2 Sequestration and Geologic InteractionsClay minerals and soil interactionsMinerals Flotation and Separation Techniques

Reflectivity Anisotropy Spectra of Cu- and Ag- (110) surfaces from {\it ab initio} theory

Patrizia Monachesi、Maurizia Palummo、Rodolfo Del Sole 等 5 位作者2000-05-12arXiv

We are able to disentagle the effects of the intraband and interband parts of the bulk dielectric function on the bare dielectric anisotropy of the surface. We show how the position, sign and amplitude of the structures observed in such spectra depend on the above quantities. The lineshape of all the calculated struct…

Materials Science

Anisotropic Compression in Dimer C60 Fullerene Solid

Narinder Kaur、Navdeep Bajwa、K. Dharamvir 等 4 位作者2000-05-12arXiv

Dimer C60 solids are monoclinic crystals with molecular longer axis aligned along the c-axis. A simple model based on atom-atom potential used to calculate various bulk, structural and thermodynamic properties of this fullerite, has also been used to investigate the pressure and temperature dependent properties such a…

Materials Science

Phononic crystals with planar defects

I. E. Psarobas、N. Stefanou、A. Modinos2000-05-12arXiv

We study the effect of planar defects in phononic crystals of spherical scatterers. It is shown that a plane of impurity spheres introduces modes of vibration of the elastic field localized on this plane at frequencies within a frequency gap of a pure phononic crystal; these show up as sharp resonances in the transmit…

cond-mat.dis-nnMaterials Science

Ab Initio Calculation of the Lattice Distortions induced by Substitutional Ag- and Cu- Impurities in Alkali Halide Crystals

Andrés Aguado、José M. López、Julio A. Alonso2000-05-12arXiv

An ab initio study of the doping of alkali halide crystals (AX: A = Li, Na, K, Rb; X = F, Cl, Br, I) by ns2 anions (Ag- and Cu-) is presented. Large active clusters with 179 ions embedded in the surrounding crystalline lattice are considered in order to describe properly the lattice relaxation induced by the introduct…

Materials Science

Metallic nanowires: multi-shelled or filled ?

G. Bilalbegovic2000-05-12arXiv

The room temperature structure of aluminum, copper and gold infinite nanowires is studied. The molecular dynamics simulation method and the same type of the embedded atom potentials made by Voter and coworkers are used. It was found that multi-shelled and various filled metallic nanowires exist depending on the metal…

Materials Science

Unusual Redox State Dependent Fermi Resonances in the Infrared Spectra of Trinuclear Ruthenium Clusters with Isocyanide Ligands

Igor S. Zavarine、Clifford P. Kubiak、Tadashi Yamaguchi 等 6 位作者2000-05-11Inorganic Chemistry

Four different redox states of the trinuclear ruthenium clusters of general formula [Ru3(μ3-O)(μ-CH3CO2)6(L)3] (L = xylyl isocyanide (1), tert-butyl isocyanide (2)) were generated electrochemically in solution and studied by reflectance infrared spectroelectrochemistry. The IR spectra in the ν(C⋮N) region show multipl…

Lanthanide and Transition Metal ComplexesMetal complexes synthesis and propertiesMagnetism in coordination complexes

Lupene-Type Triterpenes from Periploca aphylla

Ghulam Mustafa、Erum Anis、Saeed Ahmed 等 8 位作者2000-05-11Journal of Natural Products

Two new lupane derivatives, 3beta,6alpha-dihydroxylup-20(29)-ene (1) and 6alpha-hydroxylup-20(29)-en-3beta-octadecanoate (2), have been isolated from the stems of Periploca aphylla, in addition to beta-sitosterol and lupeol. The structures of 1 and 2 were determined by spectral and chemical methods. Compound 1 showed…

Phytochemical compounds biological activitiesNatural product bioactivities and synthesisPhytochemistry and Bioactive Compounds

Crystals in formulated products

Roger J. Davey、John Garside2000-05-11Oxford University Press eBooks

This chapter explores crystals in formulated products. Having developed a process for preparing a product in a crystalline form, it is important to appreciate that these crystals usually then have to be transformed into a product. In some cases, this is achieved by further chemical reaction, in others by formulation.…

Crystallization and Solubility Studies

Sedimentation and Diffusion in Suspensions of Sterically Stabilized Colloidal Platelets

F. M. van der Kooij、Albert P. Philipse、Jan K. G. Dhont2000-05-11Langmuir

Ultracentrifuge and light scattering measurements are performed to study static and dynamic properties for a suspension of well-defined platelike colloids to first order in concentration. Both the form factor and the diffusion coefficient at infinite dilution match theoretical expressions if polydispersity is incorpor…

Electrostatics and Colloid InteractionsSurfactants and Colloidal SystemsMaterial Dynamics and Properties

Synthesis and Spectroscopic Properties of Homoleptic Bis[octakis(octyloxy)phthalocyaninato] Rare Earth(III) Sandwich Complexes

Wei Liu、Jianzhuang Jiang、Da‐Ming Du 等 4 位作者2000-05-11Australian Journal of Chemistry

A series of homoleptic bis[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] rare earth(III) sandwich complexes {M[Pc(OC8H17)8]2 (M = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm) (1) and (3)–(13), and HCe[Pc(OC8H17)8]2 (2)} has been prepared by the cyclic tetramerization of 4,5-di(octyloxy)phthalonitrile on th…

Porphyrin and Phthalocyanine ChemistryMagnetism in coordination complexesMetal-Catalyzed Oxygenation Mechanisms

Clean Synthesis Using Porous Inorganic Solid Catalysts and Supported Reagents

James H. Clark、Chris N Rhodes2000-05-11Royal Society of Chemistry eBooks

Waste minimisation has a number of aims which include enhancing the intrinsic selectivity of any given process, providing a means of recovering reagents in a form which allows easy regeneration and the replacement of stoichiometric processes with catalytic ones. Solids, as catalysts or as supports for other reagents,…

Mesoporous Materials and CatalysisNanomaterials for catalytic reactionsChemical Synthesis and Reactions

Control of Pore Sizes in Mesoporous Silica Templated by Liquid Crystals in Block Copolymer−Cosurfactant−Water Systems

Pingyun Feng、Xianhui Bu、David J. Pine2000-05-11Langmuir

Colloidal silica has been polymerized in the aqueous domain of lyotropic liquid crystal phases in ternary surfactant (Pluronic F127 or P123)−cosurfactant (butanol, pentanol, or hexanol)−water systems to create optically transparent mesostructured surfactant−cosurfactant−silica monoliths. The use of ternary systems enr…

Zeolite Catalysis and SynthesisPolyoxometalates: Synthesis and ApplicationsMesoporous Materials and Catalysis

Visualization and Characterization of Poly(amidoamine) Dendrimers by Atomic Force Microscopy

J. Li、Lars T. Piehler、D. Qin 等 6 位作者2000-05-11Langmuir

Poly(amidoamine), or PAMAM, dendrimers in the G5−G10 range were imaged by tapping mode atomic force microscopy (AFM). Individual dendrimer molecules could be clearly observed in the AFM images, which showed that these dendritic particles appear to be monodispersed, dome-shaped, and randomly distributed on the mica sur…

Dendrimers and Hyperbranched PolymersPolymer Surface Interaction StudiesRNA Interference and Gene Delivery

Nanoscale Tubules Formed by Exfoliation of Potassium Hexaniobate

Geoffrey B. Saupe、Chad C. Waraksa、Hyuk-Nyun Kim 等 7 位作者2000-05-11Chemistry of Materials

The exfoliation of acid-exchanged K 4 Nb 6 O 17 with tetra( n -butyl)ammonium hydroxide in water produces a colloidal suspension of individual sheets, which roll into loosely bound tubular structures. The tubule shape can be made permanent via precipitation of the colloid with alkali cations. Atomic force microscopy a…

Polymer Surface Interaction StudiesSilicone and Siloxane ChemistryBone Tissue Engineering Materials

Magnetic Field resulting from non-linear electrical transport in single crystals of charge-ordered Pr$_{0.63}$ Ca$_{0.37}$ MnO$_{3}$}

Ayan Guha、N. Khare、A. K. Raychaudhuri 等 4 位作者2000-05-11arXiv

In this letter we report that the current induced destabilization of the charge ordered (CO) state in a rare-earth manganite gives rise to regions with ferromagnetic correlation. We did this experiment by measurement of the I-V curves in single crystal of the CO system Pr$_{0.63}$Ca$_{0.37}$MnO$_{3}$ and simultanously…

Materials ScienceStrongly Correlated Electrons

Coherent Stranski-Krastanov growth in 1+1 dimensions with anharmonic interactions: An equilibrium study

E. Korutcheva、A. -M. Turiel、I. Markov2000-05-11arXiv

The formation of coherently strained three-dimensional islands on top of the wetting layer in Stranski-Krastanov mode of growth is considered in a model in 1+1 dimensions accounting for the anharmonicity and non-convexity of the real interatomic forces. It is shown that coherent 3D islands can be expected to form in c…

Materials Sciencecond-mat.stat-mech