Materials Literature
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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…
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…
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…
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 ),…
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…
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…
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…
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…
A systematic study of the factors governing the formation of Nb-TMS1, a niobium-based mesoporous hexagonally-packed transition metal oxide molecular sieve, is reported. The synthesis of this material was achieved through a novel ligand-assisted liquid crystal templating mechanism in which a discrete covalent bond is u…
Dendritic aliphatic polyesters of one, two, three, and four generations ( M w: 906, 1856, 3754, and 7549 g/mol) were synthesized in the convergent fashion, using 2,2-bis(hydroxymethyl)propionic acid as building block and 1,1,1-tris(hydroxyphenyl)ethane as core molecule. Dendrons of one to four generations were synthes…
The development of the dynamic glass transition in poly( n -alkyl methacrylate)s is investigated with broad-band dielectric spectroscopy in the frequency range from 10 -4 to 10 9 Hz. The experimental data were analyzed by adjustment with one or a sum of two Havriliak Negami functions. Upon decreasing the temperature,…
The structure and dynamical behavior of short and long chain alkanethiols, CH 3 (CH 2 ) 7 SH and CH 3 (CH) 17 SH, and of a hydroxyalkanethiol, HO(CH 2 ) 16 SH, adsorbed onto gold nanoparticles were studied by variable temperature solid-state 13 C NMR spectroscopy. In both the solution and solid state, the resonances o…
A. Harriman and J. Sauvage, Chem. Soc. Rev., 1996, 25, 41 DOI: 10.1039/CS9962500041
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAssemblage and Alignment of the Spins of the Organic Trinitroxide Radical with a Quartet Ground State by Means of Complexation with Magnetic Metal Ions. A Molecule-Based Magnet with Three-Dimensional Structure and High TC of 46 KKatsuya Inoue, Takashi Hayamizu, Hiizu I…
Masses, Sizes, and Shapes of Macromolecules from Multifunctional Monomers From Theory to Practice: Historical Perspectives Nomenclature Synthetic Methodologies: Divergent Procedures Synthetic Methodologies: Convergent Procedures Synthetic Methodologies: One-step (Hyperbranched) Procedures Chiral Dendritic Macromolecul…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in VacuumBrian E. BentView Author Information Department of Chemistry and Columbia Radiation Laboratory, Columbia University, New York, New Yor…
Giant magnetoresistance (GMR), which was until recently confined to magnetic layered and granular materials, as well as doped magnetic semiconductors, occurs in manganate perovskites of the general formula Ln 1- x A x MnO 3 (Ln = rare earth; A = divalent ion). These manganates are ferromagnetic at or above a certain v…
Lanthanide complexation chemistry in solution is an active research theme because of the importance of gadolinium complexes as contrast agents in magnetic resonance imaging, and of luminescent europium and terbium complexes as probes in biochemistry. The physicochemical principles and theory underpinning this work are…
A new class of sterically hindered dendrimer-metalloporphyrins was synthesized for use as shape-selective oxidation catalysts. A series of oxidatively robust poly(phenylesters) dendrimers were prepared through a convergent synthesis. Monodendrons were appended to the meta -positions of the 5,10,15,20-tetrakis(3‘,5‘-hy…
Hexagonal mesoporous titanosilicates with distinguishable framework charges and textural mesoporosity, namely, Ti-MCM-41 and Ti-HMS, were prepared at ambient temperature by electrostatic and neutral assembly processes, respectively. Titanium incorporation at the 2 mol % level for both materials was accompanied by incr…