Materials Literature
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The orientation of the principal axes of the g tensor with respect to the relationship of axial ligand planes to the porphyrin nitrogens has been studied in the framework of the one-electron crystal field model for tetragonal and rhombic low-spin d 5 complexes such as ferriheme centers. All five d atomic orbitals were…
Ab initio molecular orbital calculations at various, correlated levels of theory have been performed on eight isomers of the [H,O 4,S 2 ] - anion and six forms of [H 2,O 4,S 2 ]. For the former species, the hypothetical O 3 SSOH - ( 9 ) ion is identified as the lowest energy isomer using second-order Møller−Plesset pe…
The surface chemistry of HCN on Pt(111) and Cu(100) is markedly different. On Pt(111), temperature-programmed reaction spectroscopy (TPRS) and reflection absorption infrared spectroscopy (RAIRS) show a series chemical transformations with increasing temperature, whereas on Cu(100), HCN desorbs below 170 K without diss…
A new noncentrosymmetric ternary selenite, Se 4 Nb 2 O 13, has been synthesized from SeO 2 and Nb 2 O 5 . Crystal data: Se 4 Nb 2 O 13, M r = 709.64, monoclinic, space group Pa (No. 7), a = 7.555(6) Å, b = 6.637(8) Å, c = 11.377(5) Å, β = 109.23(3)°, V = 538.64(2) Å 3 ( T = 200 K), Z = 2, R(F) = 6.44%, R w (F) = 7.12%…
The surface termination, structure, and morphology of the LaAlO3{100} surface has been studied as a function of temperature by means of time-of-flight scattering and recoiling spectrometry (TOF-SARS), atomic force microscopy (AFM), low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), and x-ray ph…
The liquid crystalline and microphase behavior of new chiral side chain liquid crystalline diblock copolymers is described. The materials, which contain a smectic C* mesogen, are block copolymers of polystyrene and methacrylates containing (s)-2-methyl-1-butyl-4‘-(((4-hydroxyphenyl)carbonyl)oxy)-1,1‘-biphenyl-4-carbox…
We study the electronic structure of ( n,0) zigzag carbon nanotubes by means of two complementary numerical methods. Using the semiempirical PM3 method, we carry out quantum-chemical calculations for tube fragments of different symmetry and size, which represent these tubes. Using the tight-binding method, we proceed…
Methyl anthranilate is a very important perfumery ester and also a precursor to a number of Schiff bases which are used in several fragrance formulations. The current practice is to use homogeneous acids as catalysts in the manufacture of methyl anthranilate either starting with isatoic anhydride and methanol or by th…
A series of poly(ferrocenyldimethylsilanes) (PFS) with narrow molar mass distribution were prepared via anionic ring-opening polymerization. The thermal behavior and morphology of these materials were investigated. Differential scanning calorimetry (DSC) experiments showed multiple melting endotherms upon heating afte…
A series of aluminophosphate-based tubular mesoporous molecular sieves without (UHM-1) and with substituted silicon (UHM-3) have been synthesized at room temperature in the presence of a cationic surfactant cetyltrimethylammonium chloride (CTACl) and an organic base tetramethylammonium hydroxide (TMAOH). Characterizat…
In order to understand the mechanism of C−NO reaction, the detailed material balance was established by analyzing all the gas species produced during the reaction with mass spectroscopy and gas chromatography. The amount of nitrogen-containing surface species was estimated in the temperature range between 600 and 950…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTTandem Hetero-Catenation: Templating and Self-Assembly in the Mutual Closure of Two Different Interlocking RingsDarren G. Hamilton, Neil Feeder, Luca Prodi, Simon J. Teat, William Clegg, and Jeremy K. M. SandersView Author Information Cambridge Centre for Molecular Rec…
The synthesis of the sterically hindered porphyrin 1 (3,7,13,17-tetramethyl-5,15-diphenylporphyrin) could only be achieved by first preparing a 5,15-meso substituted octaalkylporphyrin. Thus, the synthesis of a 2,8,12,18-tetrakis(2-hydroxyethyl)-3,7,13,17-tetramethyl-5,15-diphenylporphyrin ( 12 ) had to precede the sy…
The interaction of oxygen with Al(111) was investigated by STM at temperatures between 350 and 530 K, by annealing an oxygen precovered surface and by adsorption of oxygen on the hot surface. For exposures up to 10 L and temperatures up to 470 K a considerable part of the oxygen exists still in the chemisorbed state,…
The isotropic–nematic phase transition in semiflexible hard chain fluids is investigated via an Onsager type density functional theory. The angle-dependent excluded volume of two chains required in the theory is obtained via Monte Carlo simulations. The theory predicts an isotropic to nematic phase transition at lower…
This book is about the processing, microstructure and properties of materials in fibrous form. The range of fibrous materials covered spans natural polymeric fibres such as silk, synthetic polymeric fibres such as aramid and polyethylene, metallic fibres such as steel and tungsten, and ceramic fibres such as alumina a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolyoxoanion Chemistry Moves toward the Future: From Solids and Solutions to SurfacesWalter G. Klemperer and Craig G. WallView Author Information Department of Chemistry, University of Illinois, 601 South Goodwin Avenue, Urbana, Illinois 61801 Cite this: Chem. Rev. 1998, 98,…
The electronic structure of an infinite 1D array of vertically coupled InAs/GaAs strained quantum dots is calculated using an eight-band strain-dependent k-dot-p Hamiltonian. The coupled dots form a unique quantum wire structure in which the miniband widths and effective masses are controlled by the distance between t…
The many experimental puzzles of solid hydrogen, that seem to defy the generally accepted view of condensed matter, are shown to be a rather straightforward consequence of a new approach to condensed matter physics, that takes into account the coherent electrodynamic processes, predicted by Quantum ElectroDynamics (QE…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHomogeneous-Phase Electron-Transfer Reactions of Polyoxometalates†I. A. WeinstockView Author Information USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, Wisconsin 53705, and the Department of Chemistry, Emory University, 1515 Pierce Drive…