I. D. L. Albert、Tobin J. Marks、Mark A. Ratner1996-01-01The Journal of Physical Chemistry
The effects of applied electric fields and solvent polarity on the linear and nonlinear optical (NLO) properties of three prototypical merocyanine (donor−conjugated pathway−acceptor) chromophores of differing architectural types are analyzed using semiempirical INDO/1 calculations in the presence of imposed static ele…
Nonlinear Optical Materials ResearchMolecular spectroscopy and chiralityChemical synthesis and pharmacological studies
Cornelus F. van Nostrum、Roeland J. M. Nolte1996-01-01Chemical Communications
Phthalocyanines and related compounds can self-assemble into columnar structures in the solid and liquid crystalline state, in Langmuir–Blodgett films and in solution. This paper presents an overview of supramolecular architectures that have been constructed using several phthalocyanine and porphyrazine building block…
Molecular Sensors and Ion DetectionPorphyrin and Phthalocyanine ChemistrySupramolecular Self-Assembly in Materials
Andy C. Wang、Ad Bax1996-01-01Journal of the American Chemical Society
The backbone dihedral angle φ in polypeptides is characterized by four different J couplings: 3 J H N H α, 3 J H N C ‘, 3 J H N C β, and 3 J H α C ‘ . E.COSY and quantitative J correlation techniques have been used to measure these couplings in the protein human ubiquitin, uniformly enriched in 13 C and 15 N. Assuming…
Protein Structure and DynamicsDNA Repair MechanismsEnzyme Structure and Function
Ravi S. Kane、Robert E. Cohen、R. Silbey1996-01-01Chemistry of Materials
We have demonstrated the synthesis of PbS nanoclusters within the microphase-separated films of diblock copolymers containing carboxylic acid units on one of the blocks. Lead was selectively sequestered into the acid containing domains by treating the polymer films with tetraethyllead, and PbS was formed by subsequent…
Quantum Dots Synthesis And PropertiesPolymer Surface Interaction StudiesNanocluster Synthesis and Applications
Jaroslav Stejskal、Pavel Kratochvı́l、Steven P. Armes 等 8 位作者1996-01-01Macromolecules
Aniline was polymerized in the presence of ultrafine colloidal silica particles (hydrodynamic diameter 35 nm) in aqueous media and, given a sufficient silica concentration, colloidally stable polyaniline−silica particles were obtained. The particle size of the resulting dispersions was determined by both dynamic light…
Electrochemical sensors and biosensorsConducting polymers and applicationsAnalytical Chemistry and Sensors
Konstantin Hadjiivanov、Margarita Kantcheva、D. Klissurski1996-01-01Journal of the Chemical Society Faraday Transactions
Adsorption of carbon monoxide on CuO/SiO2(1 wt.% CuO) and Cu-ZSM-5 (11 wt.% CuO) catalysts has been studied by IR spectroscopy. CO adsorption on CuO/SiO2 leads to formation of: (i) three kinds of unstable Cu2+—CO species detected only under equilibrium CO pressure and characterized by ν(CO) at 2216, 2199 and 2180 cm–1…
Catalytic Processes in Materials SciencePhase Equilibria and ThermodynamicsCatalysis and Oxidation Reactions
Yongchi Tian、Theresa A. Newton、Nicholas A. Kotov 等 5 位作者1996-01-01The Journal of Physical Chemistry
Addition of H 2 S and H 2 Se, in different proportions, to aqueous Cd(ClO 4 ) 2 solutions containing (NaPO 3 ) 6 led to the formation of coupled composite CdS−CdSe nanoparticles. Conversely, the sequential introduction of different amounts of H 2 S and H 2 Se (or H 2 Se and H 2 S) into aqueous Cd(ClO 4 ) 2 solutions c…
Advanced biosensing and bioanalysis techniquesQuantum Dots Synthesis And PropertiesChalcogenide Semiconductor Thin Films
Charlotte M. Zaremba、Angela M. Belcher、Monika Fritz 等 9 位作者1996-01-01Chemistry of Materials
Analyses of biopolymer/calcium carbonate composites grown on inorganic abiotic substrates implanted between the shell and the shell-secreting epithelium of live red abalones ( Haliotis rufescens ) provide detailed spatial and temporal data on the in vivo assembly process that generates the shell. X-ray diffraction and…
Bone Tissue Engineering MaterialsCalcium Carbonate Crystallization and InhibitionCephalopods and Marine Biology
Reza Asiaie、Weidong Zhu、Sheikh A. Akbar 等 4 位作者1996-01-01Chemistry of Materials
Barium titanate (BaTiO 3 ) powders of varying particle sizes were grown under hydrothermal conditions at a temperature of 240 °C. This was accomplished by varying the hydroxide concentration of the reaction medium as well as the time required for synthesis. The spectroscopic, thermal, and microscopic characteristics o…
Ferroelectric and Piezoelectric MaterialsDielectric materials and actuatorsMicrowave Dielectric Ceramics Synthesis
T. Beutel、János Sárkány、G.D. Lei 等 5 位作者1996-01-01The Journal of Physical Chemistry
Motivated by the unique catalytic activity of Cu/ZSM-5 in the decomposition of NO to N 2 + O 2, the redox chemistry of Cu in zeolite ZSM-5 has been studied using FTIR, TPR, EPR, and EXAFS. Isolated ions, Cu 2+, oxocations, [Cu−O−Cu] 2+, and oxide particles have been identified. Their relative abundances depend on the…
Catalytic Processes in Materials ScienceZeolite Catalysis and SynthesisCatalysis and Oxidation Reactions
Satyam Priyadarshy、Michael J. Therien、David N. Beratan1996-01-01Journal of the American Chemical Society
We describe the theoretical basis for the exceptionally large molecular first hyperpolarizabilities inherent to (5,15-diethynylporphinato)metal-bridged donor−acceptor (D−A) molecules. β values relevant for hyper-Rayleigh experiments are calculated at 1.064 and 0.830 μm for a complex with such a structure, [5-((4‘-(dim…
Porphyrin and Phthalocyanine ChemistryNonlinear Optical Materials ResearchPhotochemistry and Electron Transfer Studies
Hiromi Yamashita、Masaya Matsuoka、Kouji Tsuji 等 6 位作者1996-01-01The Journal of Physical Chemistry
The characterization of the coordination geometry of copper ions included within zeolites has been carried out with a combination of in-situ XAFS, photoluminescence, and IR measurements in order to obtain a detailed description of the formation of isolated Cu + monomers with planar 3-coordinate or linear 2-coordinate…
Catalytic Processes in Materials ScienceMesoporous Materials and CatalysisInorganic and Organometallic Chemistry
Kevin Cowtan、P. C. Main1996-01-01Acta Crystallographica Section D Biological Crystallography
A variety of density-modification techniques are now available for improving electron-density maps in accordance with known chemical information. This modification must, however, always be constrained by consistency with the experimental data. This is conventionally achieved by alternating cycles of map modification i…
Advanced Chemical Physics StudiesMachine Learning in Materials ScienceElectron and X-Ray Spectroscopy Techniques
Hiromi Yamashita、Ichihashi, Yuichi、Masakazu Anpo 等 6 位作者1996-01-01The Journal of Physical Chemistry
Titanium oxide species anchored in the Y-zeolite cavities by an ion-exchange method exhibits a high and unique photocatalytic reactivity for the direct decomposition of NO into N 2, O 2, and N 2 O at 275 K with a high selectivity for the formation of N 2 . The in situ photoluminescence and XAFS (XANES and FT-EXAFS) in…
Advanced Photocatalysis TechniquesCatalytic Processes in Materials ScienceGas Sensing Nanomaterials and Sensors
Mark Morey、Anne Davidson、Hellmut Eckert 等 4 位作者1996-01-01Chemistry of Materials
The high hydroxyl content of mesoporous silicates makes it possible to use them as anchors for the attachment of transition-metal species. In the present study, three different samples corresponding to atomic V/Si ratio of 0.01, 0.05, and 0.10 have been prepared by reacting a silica-based mesoporous matrix of the cubi…
Mesoporous Materials and CatalysisPolyoxometalates: Synthesis and ApplicationsCatalysis and Oxidation Reactions
Daniel L. Akins、Han-Ru Zhu、Chucai Guo1996-01-01The Journal of Physical Chemistry
Electronic absorption, fluorescence and fluorescence excitation spectra, and vibrational Raman spectra of selected homogeneous solution phase, free-base tetraaryl-substituted porphyrins specifically, tetraphenylporphine (TPPH 2 ), tetra( p -pyridyl)porphine (TPyPH 2 ), tetra( p - N -methylpyridyl)porphine (TMPyPH 2 ),…
Porphyrin and Phthalocyanine ChemistryPhotochemistry and Electron Transfer StudiesLuminescence and Fluorescent Materials
Ravi Verma、Hervé Marand、Benjamin S. Hsiao1996-01-01Macromolecules
In this paper, we present results of morphological studies during long time melt crystallization and subsequent melting in poly(aryl ether ether ketone) (PEEK). Morphological changes were monitored via small angle X-ray scattering (SAXS). SAXS data were analyzed via a combination of the correlation and interface distr…
Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties
Carol L. Bowes、Geoffrey A. Ozin1996-01-01Advanced Materials
The self‐assembly of inorganic open framework structures has blossomed during the 1990s. Following a short historical summary of the field, the main features of the major classes of microporous materials—cyanide open‐frameworks, chalcogenides, polychalcogenides and thio‐pnictates—are described. The Review concludes wi…
Metal-Organic Frameworks: Synthesis and ApplicationsCrystal Structures and PropertiesPolyoxometalates: Synthesis and Applications
Yuri Lvov、Katsuhiko Ariga、Izumi Ichinose 等 4 位作者1996-01-01Langmuir
Organized ceramic/polymer nanocomposites were designed from montmorillonite clay (Mont), cationic poly(ethylenimine) (PEI) or poly(dimethyldiallylammonium chloride) (PDDA) and proteins. Ordered multilayers with a controllable number of layers were prepared by alternate adsorption of delaminated montmorillonite (0.03 w…
Mesoporous Materials and CatalysisPolymer Surface Interaction StudiesDiatoms and Algae Research
David M. Antonelli、Jackie Y. Ying1996-01-01Chemistry of Materials
The synthesis and characterization of Ta-TMS1, a new member of a growing family of hexagonally packed transition-metal oxide mesoporous molecular sieves (termed TMS1) is described. Ta-TMS1 exhibits a hexagonal array of pores which can be varied in size from 20 to 40 Å and surface areas of over 500 m 2 /g. The thermal…
Catalytic Processes in Materials ScienceZeolite Catalysis and SynthesisMesoporous Materials and Catalysis