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Thermal behaviour of copper(II), nickel(II), cobalt(II) and palladium(II) complexes of N,N-dimethyl-N'-benzoylthiourea

Göktürk Avşar、Nevzat Külcü、Hakan Arslan2002-06-12TURKISH JOURNAL OF CHEMISTRY

synthesised. The thermal decomposition of these metal complexes was investigated by TG, DTG and DTA. A GC-MS combined system was used to identify the products during pyrolytic decomposition. The pyrolytic end-products were identified by X-ray powder diffraction. The thermoanalytical data of these complexes are present…

Metal complexes synthesis and propertiesThermal and Kinetic AnalysisChemical Thermodynamics and Molecular Structure

Synthesis of model polycyclohexylene/polyethylene miktoarm star copolymers with three and four arms

Thodoris Tsoukatos、Nikos Hadjichristidis2002-06-12Journal of Polymer Science Part A Polymer Chemistry

Abstract The synthesis of well‐defined 3‐ and 4‐miktoarm star copolymers of the A 2 B and A 3 B types is described, where A is 1,4‐polybutadiene and B is poly(1,3‐cyclohexadiene). The synthetic approach involves the reaction of poly(1,3‐cyclohexadienyl)lithium with an excess of methyltrichlorosilane or tetrachlorosila…

Polymer crystallization and propertiesAdvanced Polymer Synthesis and CharacterizationPolymer Nanocomposites and Properties

Synthesis and properties of new soluble aromatic polyamides and polyimides on the basis of N,N′‐bis(3‐aminobenzoyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

Guey‐Sheng Liou、Sheng‐Huei Hsiao2002-06-12Journal of Polymer Science Part A Polymer Chemistry

Abstract A new N ‐phenylated amide ( N ‐phenylamide) unit containing aromatic diamine, N , N ′‐bis(3‐aminobenzoyl)‐ N , N ′‐diphenyl‐1,4‐phenylenediamine, was prepared by the condensation of N , N ′‐diphenyl‐1,4‐phenylenediamine with 3‐nitrobenzoyl chloride, followed by catalytic reduction. Two series of organosoluble…

Epoxy Resin Curing ProcessesSynthesis and properties of polymersSilicone and Siloxane Chemistry

In situ sol‐gel process of polystyrene/silica hybrid materials: Effect of silane‐coupling agents

Jyongsik Jang、Hwanseok Park2002-06-12Journal of Applied Polymer Science

Abstract The polystyrene–silica hybrid materials have been successfully prepared from styrene and tetraethoxysilane in the presence of silane‐coupling agents by an in situ sol‐gel process. Triethoxysilyl group can be incorporated into polystyrene as side chains by the free‐radical copolymerization of polystyrene with…

Polymer Nanocomposites and PropertiesMesoporous Materials and CatalysisSilicone and Siloxane Chemistry

Electrical Switching in π-Resonant 1D Intermolecular Channels

Alain Rochefort、Richard Martel、Phaedon Avouris2002-06-12Nano Letters

We studied the influence of π-orbital coupling in a 1D stack of 4,4‘-biphenyldithiol (BDT) on the resulting electronic and electrical properties of the assembly. The conduction and the field-switching properties of the BDT assembly are compared as the intermolecular distances are reduced to below 4 Å. The system in th…

Organic Electronics and PhotovoltaicsMolecular Junctions and NanostructuresOrganic and Molecular Conductors Research

Density Functional Study on the Adsorption of Pyrazole onto Silver Colloidal Particles

Gianni Cardini、Maurizio Muniz‐Miranda2002-06-12The Journal of Physical Chemistry B

The adsorption of pyrazole onto silver colloids has been investigated by surface-enhanced Raman scattering (SERS) experiments for normal and deuterated ligand and by ab initio density functional theory (DFT) calculations performed for surface complex models. The best agreement between observed and calculated frequenci…

Gold and Silver Nanoparticles Synthesis and Applicationsnanoparticles nucleation surface interactionsSurface and Thin Film Phenomena

Dissolution Kinetics, Step and Surface Morphology of Magnesite (104) Surfaces in Acidic Aqueous Solution at 60 °C by Atomic Force Microscopy under Defined Hydrodynamic Conditions

Steven R. Higgins、Lawrence H. Boram、Carrick M. Eggleston 等 6 位作者2002-06-12The Journal of Physical Chemistry B

Dissolution of the (104) surface of magnesite (MgCO 3 ) was studied as a function of bulk solution pH over the range 2.0 < pH < 5.0 at 60 °C using atomic force microscopy (AFM) with well-defined hydrodynamics. The experimental data and corresponding solution of the convective-diffusion equation for the system revealed…

Calcium Carbonate Crystallization and InhibitionMinerals Flotation and Separation TechniquesIron oxide chemistry and applications

Exciton Dynamics in a One-Dimensional Self-Assembling Lyotropic Discotic Liquid Crystal

Rhian E. Hughes、Simon P. Hart、D. A. Smith 等 6 位作者2002-06-12The Journal of Physical Chemistry B

The steady state and time resolved phophysical properties of a novel self-assembling lyotropic discotic liquid crystal, 2,3,6,7,10,11-hexa-(1,4,7-trioxaoctyl)-triphenylene (TP6EO2M) are reported. The spectral changes that accompany the formation of linear aggregates in D2O provide no evidence of excited-state delocali…

Liquid Crystal Research AdvancementsSpectroscopy and Quantum Chemical StudiesNonlinear Dynamics and Pattern Formation

Silica reinforcement of synthetic diene rubbers by sol–gel process in the latex

Kazumasa Yoshikai、Tetsuro Ohsaki、Mutsuhisa Furukawa2002-06-12Journal of Applied Polymer Science

Abstract Styrene–butadiene rubber (SBR) and nitrile rubber (NBR) were reinforced with silica by the sol–gel method of tetraethoxysilane (TEOS) in latex. The sol–gel reaction proceeded in the mixture of latex, TEOS, water, and a catalyst. The compound that involved silica was crosslinked with the curing agent at 150°C.…

Polymer Nanocomposites and PropertiesPolymer composites and self-healingSilicone and Siloxane Chemistry

Synthesis and properties of high oil‐absorbent 4‐tert‐butylstyrene‐EPDM‐divinylbenzene graft terpolymer

Mei Hua Zhou、Won‐Jei Cho2002-06-12Journal of Applied Polymer Science

Abstract The graft crosslinking polymerization of 4‐ tert ‐butylstyrene (tBS) and divinylbenzene (DVB) onto ethylene–propylene–diene (EPDM) was carried out in toluene by using benzoyl peroxide (BPO) as an initiator. The synthesized graft terpolymer, tBS‐EPDM‐DVB (PBED), was extracted with tetrahydrofuran (THF) into ge…

Surface Modification and SuperhydrophobicityPolymer Nanocomposites and PropertiesPolymer composites and self-healing

Symmetry-Breaking Phenomena in Metalloporphyrin π-Cation Radicals

Torgil R. Vangberg、Renate Lie、Abhik Ghosh2002-06-12Journal of the American Chemical Society

Density functional theory (DFT) calculations of the energetics, molecular structures, and spin density profiles of metalloporphyrin pi-cation radicals suggest that the common practice of describing these radicals in terms of a universal A(1u)/A(2u) dichotomy is often not justified, confirming a possibility first fores…

Porphyrin and Phthalocyanine ChemistryPhotochemistry and Electron Transfer StudiesMetal-Catalyzed Oxygenation Mechanisms

Foam drainage: A film contribution?

Vincent Carrier、S. Destouesse、Annie Colin2002-06-12Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics

We have measured the steady drainage of foams of various surfactants, varying the size of the parietal plateau borders from 0.24 to 2.4 mm. We report an evolution of the power laws of drainage with the bubble size, which cannot be explained by the most recent developments of the drainage theory. We believe that one re…

Enhanced Oil Recovery TechniquesPolymer composites and self-healingPickering emulsions and particle stabilization

Donnan Permselectivity in Layer-by-Layer Self-Assembled Redox Polyelectrolye Thin Films

Ernesto J. Calvo、Alejandro Wolosiuk2002-06-12Journal of the American Chemical Society

Redox polyelectrolyte multilayers have been assembled with use of the layer-by-layer (LBL) deposition technique with cationic poly(allylamine) modified with Os(bpy)(2)ClPyCHO (PAH-Os) and anionic poly(styrene)sulfonate (PSS) or poly(vinyl)sulfonate (PVS). Different behavior has been observed in the formal redox potent…

Conducting polymers and applicationsPolymer Surface Interaction StudiesMolecular Junctions and Nanostructures

Crystalline Orientation in Syndiotactic Polystyrene Cast Films

Paola Rizzo、Marina Lamberti、Alexandra R. Albunia 等 5 位作者2002-06-12Macromolecules

The kind and degree of crystalline phase orientation for clathrate s-PS films, obtained by solution-casting procedures, and for semicrystalline films, obtained by suitable treatments on these cast films, are analyzed. Clathrate as well as nanoporous form films can present high degrees of uniplanar orientation, corresp…

Corrosion Behavior and InhibitionCopper Interconnects and ReliabilityAnodic Oxide Films and Nanostructures

Do Nonplanar Distortions of Porphyrins Bring about Strongly Red-Shifted Electronic Spectra? Controversy, Consensus, New Developments, and Relevance to Chelatases

Hege Ryeng、Abhik Ghosh2002-06-12Journal of the American Chemical Society

TDDFT calculations confirm a controversial proposal by DiMagno and co-workers that ruffling distortions, by themselves, do not bring about sizable red shifts in the electronic absorption spectra of "simple" nontransition-metal porphyrins. We now report that the same also holds for saddling distortions. The situation i…

Photosynthetic Processes and MechanismsPorphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation Mechanisms

Exciplex Intermediates in Photoinduced Electron Transfer of Porphyrin−Fullerene Dyads

Tero Kesti、Nikolai V. Tkachenko、Visa Vehmanen 等 7 位作者2002-06-12Journal of the American Chemical Society

The photoinduced electron transfer in differently linked zinc porphyrin-fullerene dyads and their free-base porphyrin analogues was studied in polar and nonpolar solvents with femto- to nanosecond absorption and emission spectroscopies. A new intermediate state, different from the locally excited (LE) chromophores and…

Porphyrin and Phthalocyanine ChemistryFullerene Chemistry and ApplicationsPhotochemistry and Electron Transfer Studies

Structural and Mechanistic Investigations of the Oxidation of Dimethylplatinum(II) Complexes by Dioxygen

Vsevolod V. Rostovtsev、Lawrence M. Henling、Jay A. Labinger 等 4 位作者2002-06-12Inorganic Chemistry

The oxidation of (tmeda)Pt(II)(CH(3))(2) (1, tmeda = N,N,N',N'-tetramethylethylenediamine) to (tmeda)Pt(IV)(OH)(OCH(3))(CH(3))(2) (3) by dioxygen in methanol proceeds via a two-step mechanism. The initial reaction between (tmeda)Pt(CH(3))(2) and dioxygen yields a hydroperoxoplatinum(IV) intermediate, (tmeda)Pt(OOH)(OC…

Polyoxometalates: Synthesis and ApplicationsMetal-Catalyzed Oxygenation MechanismsOxidative Organic Chemistry Reactions

New DNLS Equations for Anharmonic Vibrational Impurities

M. I. Molina2002-06-12arXiv

We examine some new DNLS-like equations that arise when considering strongly-coupled electron-vibration systems, where the local oscillator potential is anharmonic. In particular, we focus on a single, rather general nonlinear vibrational impurity and determine its bound state(s) and its dynamical selftrapping propert…

cond-mat.dis-nnMaterials Science

Failure time in the fiber-bundle model with thermal noise and disorder

Antonio Politi、Segio Ciliberto、Riccardo Scorretti2002-06-12arXiv

The average time for the onset of macroscopic fractures is analytically and numerically investigated in the fiber-bundle model with quenched disorder and thermal noise under a constant load. We find an implicit exact expression for the failure time in the low-temperature limit that is accurately confirmed by direct si…

cond-mat.dis-nnMaterials Sciencecond-mat.stat-mech

Photoluminescence of Tetragonal ZrO2 Nanoparticles Synthesized by Microwave Irradiation

Jiahe Liang、Zhaoxiang Deng、Xin Jiang 等 5 位作者2002-06-12Inorganic Chemistry

Polymer-stabilized tetragonal ZrO(2) nanopowders with average size of ca. 2.0 nm have been prepared by microwave heating in an aqueous solution containing Zr(NO(3))(4) x 5H(2)O, PVA, and NaOH. The photoluminescence of the synthesized ZrO(2) fine particles has been investigated.

Luminescence Properties of Advanced MaterialsCatalytic Processes in Materials ScienceMicrowave Dielectric Ceramics Synthesis