Materials Literature
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Beer's law and linear superposition of absorption spectra are known to be valid in dilute solutions. In this work it is shown with two examples that in a condensed phase conducting polymers are subject to the frequency-dependent local field of lightwave, also called dielectric effect, which influences the absorbance,…
The possibility of fabricating thermoelectric coolers using thin film deposition and micromachining is investigated. The processing sequences described facilitate fabrication of the thermoelectric cooler and electronic components, such as laser diodes, CCD and infrared detectors, as elements of an integrated circuit.…
An organic trialdehyde, TRIPOD (2), was designed as a template for the synthesis of a three-helix bundle protein. Crystallographic data indicate that the aldehyde groups are appropriately spaced to maximize hydrophobic interactions between the chains of the protein. Peptide strands were attached to the template by red…
This paper explores the copolymerization of l -lactide ( l -LA) with 2,2-[2-pentene-1,5-diyl]trimethylene carbonate ( c HTC). Since c HTC has a cyclohexene group, this provided a route for preparing poly(lactic acid), (PLA), based chains decorated with controlled quantities of C C substituents. Ring-opening copolymeri…
The syntheses and fluid-solution EPR spectra of nitroxide-substituted porphyrins 1-3 are described. The phenylnitroxide is attached to the meso-position of three porphyrins: (a) directly through a single bond (1); (b) through an ethenyl group (2); and (c) through an ethynyl group (3). The spin distribution in each of…
The luminescence properties of Eu 3+ encapsulated in sol−gel-derived optically transparent silica gels were investigated by time-resolved laser spectroscopy. At the xerogel stage, the emission spectra originated mainly from Eu 2+ at 410 nm, and only a small contribution from Eu 3+ at 580 nm and electron−hole (e - −h +…
Quasicrystals are materials of both intellectual and practical importance. Although some level of understanding can now be applied to their bulk electronic and atomic structure, the same cannot be said of their surface properties. In this article, we point out some of the key issues in the surface science of quasicrys…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis of the First Organic Polymer/Polyphosphazene Block Copolymers: Ambient Temperature Synthesis of Triblock Poly(Phosphazene−ethylene oxide) CopolymersJames M. Nelson, A. Paul Primrose, Thomas J. Hartle, Harry R. Allcock, and…
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…