Materials Literature
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The porphyrin–crown ether derivatives described here exhibit affinities to unprotected peptides of hitherto unknown magnitude in aqueous solution; the optical signal built-in to porphyrin receptors makes these applicable also to sensor techniques; the results can also form the basis of new catalytic systems, e.g. for…
Lumazine synthase catalyzes the penultimate step in the synthesis of riboflavin in plants, fungi, and microorganisms. The enzyme displays two quaternary structures, the pentameric forms in yeast and fungi and the 60-meric icosahedral capsids in plants and bacteria. To elucidate the structural features that might be re…
A strong case has been made by several authors that sharp, spherically symmetric shocks converging on the center of a spherical bubble driven by a strong acoustic field give rise to rapid compression and heating that produces the brief flash of light known as sonoluminescence. The formation of such shocks is considere…
We report a method to fabricate Ångstrom size pores in poly(methylsilsesquioxane) films in order to decrease the density and the dielectric constant of the film. Copolymers bearing methyl(trisiloxysilyl)units and alkyl(trisiloxysilyl) units are spin-coated and baked at 250 °C to provide rigid siloxane matrixes. Films…
Point contact and tunnelling experiments performed at low temperatures were used to study the electronic behaviour of the icosahedral quasicrystalline alloys AlPdRe, AlCuFe, and AlPdMn. With samples of high quality we observed at low temperatures a zero-bias anomaly that we related to the decrease of the electronic de…
The dielectric constant and the leakage current density of (Ba, Sr)TiO/sub 3/ (BST) thin films deposited on various bottom electrode materials (Pt, Ir, IrO/sub 2//Ir, Ru, RuO/sub 2//Ru) before and after annealing in O/sub 2/ ambient were investigated. The improvement of crystallinity of BST films deposited on various…
Protein crystals contain many kinds of disorder, but only a small fraction of these are likely to be important in limiting the diffraction properties of interest to crystallographers. X-ray topography, high-angular-resolution reciprocal space measurements, and standard crystallographic data collection have been used t…
Recent results suggests that CuAlO 2 may be a p‐type transparent conductor, but thin film synthesis is difficult because of the complex Cu : Al : O phase diagram. We report a robust method of making c ‐axis oriented CuAlO 2 thin films. Thin film precursors of CuAlO 2 were deposited on sapphire (001) substrates by radi…
The versatility of the one-pot synthesis of organically modified silicas is shown by the preparation of materials with very high loadings (up to 4.85 mmol g–1) and by the synthesis of bifunctional catalysts. The synthesis of these materials is shown to be very atom efficient, with all the Si species being incorporated…
We have employed variable temperature scanning tunnelling microscopy (STM) to probe the surface structure of the TiO2(110) surface with clean, adsorbate and metal covered terminations. The aim of the work is to understand the nature of catalysis on supported metal oxide catalysts for which a good model is an admetal o…
The nucleation and growth of mesoporous silica fibers and gyroids was the focus of this kinetic study. The authors obtained images of the smallest objects implicated in the creation of these shapes by tapping-mode atomic force microscopy and transmission electron microscopy. Dynamic light scattering provided temporal…
The synthesis of a series of diphosphine ligands having phosphorus donor atoms in the core of a carbosilane dendrimer and their use in palladium catalysed allylic alkylation is described.
A three-dimensional conductive superstructure of 12 ± 1 nm Au-nanoparticles was built up on a conductive (indium-doped tin oxide) glass support by means of alternating treatments with Au-nanoparticle and cyclobis(paraquat-p-phenylene) tetrachloride solutions. The structure was characterized by absorbance spectroscopy…
A manganese molybdenum phosphate, (NH3CH2CH2NH3)10(H3O)3(H5O2)Na2[MnMo12O24(OH)6 (PO4)4(PO3OH)4][MnMo12O24 (OH)6(PO4)6(PO3OH)2]·9H2O, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. The structure of this compound may be considered to be two [Mo6O12(OH)3(PO4)2(HPO…
A novel mixed-metal oxide solid [H6Mn3VIV15VV4O46(H2O)12]·30H2O (1) has been synthesized and characterized. The structure of the mixed-valence compound consists of three-dimensional arrays of “spheres” of {V19O46}, each one linked by six μ2-{Mn(H2O)4} bridges to six neighboring {V19O46} units, generating a complex 3-D…
Low dielectric constant, porous silica was made from commercially available methyl silsesquioxane (MSQ) by the addition of a sacrificial polymer, substituted norbornene polymer containing triethoxysilyl groups (NB), to the MSQ. The silsesquioxane‐NB polymer film mixture was thermally cured followed by decomposition of…
Organically-modified silicates have been synthesized from RSi(OEt) 3 (R=CH 3 , C 2 H 5 , C 8 H 17 , CH 2 =CH or C 6 H 5 ) and TEOS under acidic conditions, in the presence of cetyltrimethylammonium bromide (CTAB). The introduction of RSiO 1.5 units with R/Si=0.2:1, prevents the system from adopting a high degree of he…
The results of the first Critical Assessment of Fully Automated Structure Prediction (CAFASP-1) are presented. The objective was to evaluate the success rates of fully automatic web servers for fold recognition which are available to the community. This study was based on the targets used in the third meeting on the C…
An icosahedral quasicrystalline phase was found to precipitate as a primary phase from the supercooled liquid in the Zr65Al7.5Ni10Cu17.5−xPdx (x=5 and 10 at%) amorphous alloys. No icosahedral phase is formed for the present Zr65Al7.5Ni10Cu17.5 alloy and hence the addition of Pd promotes the precipitation of the icosah…
Control of the microarchitecture in a metallo-supramolecular double-helical array results from inter-strand edge–face π-stacking interactions which pull the ligand strands together thereby creating two distinct helical grooves (major and minor).