Materials Literature
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The synthesis and characterization of seven (Zn II ) 2 bis(porphyrin) molecules are described. The molecular structures of two bis(porphyrin)s ( 6 and 7 ) were determined by X-ray diffraction methods. Four of the compounds have their porphyrin moieties attached in a meta -fashion to a substituted benzene ring ( 1 − 4…
Polyaniline specimens, emeraldine sulfate, emeraldine hydrochloride, and emeraldine base, were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, elastic peak electron spectroscopy, and density measurements using helium pycnometry. This work has been stimulated by a considerable interest in pote…
The magnetic anisotropy of the two cyclic hexanuclear Fe(III) clusters [Li⊂Fe 6 L 6 ]Cl·6CHCl 3 and [Na⊂Fe 6 L 6 ]Cl·6CHCl 3, L = N(CH 2 CH 2 O) 3, was investigated. Based on a spin Hamiltonian formalism, the magnetic anisotropy was calculated exactly to first order, i.e., in the strong exchange limit, using Bloch's p…
The effect of water vapor concentration on the reaction rates of NH 3 oxidation and N 2 O decomposition catalyzed by calcined limestone was investigated by use of a fixed bed reactor under atmospheric fluidized bed combustion conditions. Both reactions were inhibited by the presence of water vapor. Inhibition of NH 3…
Aromatic polymers are widely used in products ranging from optical lenses to milk bottles because of their strength, thermal durability, and high glass transition temperatures. All of the commonly used routes employed to generate aromatic polycarbonates and polyesters generate large amounts of waste as by-products and…
Salts of the edge-sharing bitetrahedral anion [M 2 Cl 6 ] 2 - with M = Mn, Fe, and Co were prepared in high yields by reaction of MCl 2 with 1 equiv of chloride ion. The anion [Fe 2 Cl 6 ] 2 - was isolated with five different cations, namely, [PPh 4 ] + ( 1 ), [Et 4 N] + ( 2 ), [ppn] + ( 3 ), [AsPh 4 ] + ( 4 ), and [H…
Effective light-harvesting arrays require multiple photoactive energy donors that funnel energy to an energy acceptor. Porphyrins and phthalocyanines are attractive components for light-harvesting arrays due to their strong absorption in the blue and red regions, respectively, and because energy transfer can occur fro…
The photoinduced anisotropy in polymers and copolymers with a mesogenic and a nonmesogenic azobenzene moiety in the side chain were investigated. The results of the light-induced optical anisotropy study in thin films obtained by means of polarized UV−vis and IR absorption spectroscopy are presented. Starting from in-…
Light-harvesting arrays containing four porphyrins covalently linked to a phthalocyanine in a star-shaped architecture have been synthesized. Cyclotetramerization of an ethyne-linked porphyrin−phthalonitrile in 1-pentanol in the presence of MgCl 2 and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) afforded the all-magnesium…
The stability of oil-in-water emulsions to both creaming and coalescence was measured as a function of salt concentration in heptane + water mixtures stabilized by sodium bis(2-ethylhexylsulfosuccinate) (AOT). Emulsions were prepared from pre-equilibrated phases in Winsor I systems. Up to 0.035 M NaCl, the creaming ra…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTCocondensation of Organosilica Hybrid Shells on Nanoparticle Templates: A Direct Synthetic Route to Functionalized Core−Shell ColloidsSimon R. Hall, Sean A. Davis, and Stephen MannView Author Information School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K. Cite thi…
The phase separation process in a thermoplastic-modified epoxy system was studied using rheological dynamic analysis (RDA) and differential scanning calorimetry (DSC). Transmission electronic microscopy (TEM) was used to get direct representation of morphologies at different times during the phase separation process.…
Proton, low-resolution T 2 NMR relaxation experiments are used to study the adsorption of EPDM to the surface of carbon blacks and the structure of the physical EPDM/carbon black network in cured and uncured compounds. It is shown that a layer of immobilized EPDM is formed at the carbon black surface after mixing. The…
The buildup of the first layers of a polystyrenesulfonate (PSS)/polyallylamine (PAH) multilayer is studied in situ by means of streaming potential measurements (SPM) and by scanning angle reflectometry (SAR). The results are discussed in the framework of a schematic representation of the multilayer in three zones: a p…
The MgSO 4 :Dy, P and MgSO 4 :Dy, P, Cu phosphors have been developed and studied by the thermoluminescence (TL) glow curves and dose responses to gamma radiation. The TL sensitivity of MgSO 4 :Dy, P phosphor is higher than that of LiF:Mg, Ti. One main dosimetric peak at about 283.6 °C and a satellite peak at about 35…
Stoichiometric LiMn 2 O 4 undergoes a structural phase transition close to room temperature from cubic to orthorhombic symmetry. The crystal structure at 230 K (space group Fddd and a = 24.743(1), b = 24.840(1), and c = 8.199(1) Å) corresponds to an orthorhombic ∼ 3a × 3a × a superstructure of the cubic spinel structu…
The cuboctameric hydroxysilsesquioxane ( c -C 5 H 9 ) 7 Si 8 O 12 (OH) ( 2 ), obtained after hydrolysis of ( c -C 5 H 9 ) 7 Si 8 O 12 Cl ( 1 ), and triphenylsilanol have been applied as model supports for silica-grafted olefin polymerization catalysts. The ligands were introduced on group 4 metals by either chloride m…
The formation of fatty plaques (atherosclerosis) that clog arteries is one of the most common forms of cardiovas-cular disease. The only permanent solu-tion is surgical replacement of diseased arteries with healthy autologous veins (that is, veins from the same patient). However, this type of surgery is only possible…
We used our previously implemented GW approximation (GWA) based on the all-electron full-potential projector augmented wave (PAW) method to study the optical properties of small, medium and large-band-gap semiconductors: Si, GaAs, AlAs, InP, Mg$_2$Si, C, and LiCl. The aim being to study the size of both local-field (L…
We have studied the dynamics of electrons in single wall carbon nanotubes using femtosecond time-resolved photoemission. The lifetime of electrons excited to the pi* bands is found to decrease continuously from 130 fs at 0.2 eV down to less than 20 fs at energies above 1.5 eV with respect to the Fermi level. This shou…