Materials Literature
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Dimethyl[2,4-dioxo(1 H,3 H)pyrimido]tetrathiafulvalene (1) and dimethyl-[2-amino-4-oxo(3 H)pyrimido]tetrathiafulvalene (4) form unusual inner salts by oxidation in the presence of bases. The insoluble black-green betaines 2 and 5 react with acids to form cation radical salts. Betaine 2 in the presence of acid and bis-…
Abstract In this work, short carbon fibers were blended with poly(vinyl chloride) (PVC) plastisol forming a conductive network of the fibers in the composite. The effects of concentration and initial length of the carbon fibers on the conductivity of the network were studied. For an initial fiber length of 3 mm (L/D =…
We have identified a novel cardiac steroid, 11,19-epoxy-19-methoxytelocinobufagin, named marinosin (1), in the skin of the toad, Bufo marinus (L.) Schneider. The treatment of compound 1 with 50% CH3CN containing 0.1% trifluoroacetic acid yielded a 11 alpha-hydroxyhellebrigenin (2), which has not previously been isolat…
Organosilicon hydrides are oxidized to the corresponding silanols in high yield in a homogenous phase in the presence of a small amount of water and a catalytic amount of a rhodium complex.
Nanophase SiC/Si3N4 composite powders were synthesized by the carbothermal nitridation of SiO2. These powders have desirable characteristics of high quality with oxygen contents on the order of 1.5 to 2 wt. %, surface area of ∼ 10 m2/g, submicron α-Si3N4, low metallic impurity levels, and a homogeneous distribution of…
New linearly extended π-electron donors based on bridged dithienylethylene (DTE) end-capped with diversely substituted 1,3-dithiol-2-ylidene electron-releasing groups have been synthesized by Wittig–Horner olefination of appropriate aldehydes. Cyclic voltammetry shows that whereas the unbridged analogues are directly…
The reaction of the Group 2 metal hydroxides, oxides or carbonates in 95% ethanol in the presence of a suitable glyme ligand L–L [i.e. Me(OCH 2 CH 2 ) n OMe, n = 3, 4 or 7] and a β-diketone, has yielded either [M(β-diket) 2 (L–L)] or [{M(β-diket) 2 } 2 (L–L)] [M = Mg–Ba; β-diket = Htmhd (2,2,6,6-tetramethylheptane-3,5…
Novel fluoroarylporphyrins bearing electron donor dimethylamino groups in the meso-aryl positions and an electron acceptor nitro group on one of the pyrrole carbons exhibit significant solvent dependent fluorescence spectra and time-resolved emission properties. These effects are suggestive of intramolecular charge tr…
Symmetrically tetrasubstituted metal-free and metal phthalocyanines (M = 2H, Cu, Ni, Co, Zn or Fe) with four 15-membered heteroatom (N, O, S)-containing donor sites attached have been synthesized and characterized by elemental analysis, IR, NMR, UV/VIS spectroscopy and thermogravimetric analysis.
Composite materials reinforced with braided, woven, knit, and stitched fibrous preforms are emerging as potential alternatives to unidirectional prepreg tape. A variety of these material forms are currently being evaluated by major airframe manufacturers.
Abstract The structural properties of alumina as well as its fluoride and sodium modifications were characterized by X‐ray diffraction, infrared spectroscopy and differential thermal analysis. We have shown, that fluoride ions interact with hydroxyls type Ia of γ‐Al 2 O 3 forming Al–F species, which then react at 400…
Luminescence of Eu 3+ and Tb 3+ intercalated in K 2-x H x Ti 2 O 5 layered oxides is observed by exciting the layered titanate host indicating that the energy transfer via electron–hole trapping from the layered host to the guest in the interlayers occurred.
This work evaluates the sorption potential of an hydrotalcite compound [Mg3Al(OH)8]2CO3H2O, HT, and its calcined product Mg3AlO4(OH), HT500, for sodium dodecylbenzenesulfonate, DBS, in water. The results obtained by spectrophotometric measurements show that the adsorption of DBS in HT was low, while in the HT500 the a…
A new layered perovskite compound, NaLaTa2O7, was synthesized by ion-exchange reaction of the rubidium compound, RbLaTa2O7. The crystal structure of the compound was determined by the Rietveld analysis for powder X-ray diffraction pattern. The crystal structure is analogous to that of the corresponding niobate compoun…
We review briefly the Adam-Gibbs-Goldstein approach to understanding the phenomenology of glassforming liquids and note three ways of scaling viscosity or relaxation time data which emphasize different aspects of the relationship between fragile and strong behavior in supercooling liquids. In all these cases, evolutio…
The reaction of LiBu n with [(mes) 2 P(H)O] affords the diorganophosphinate complex [(mes) 2 P(O) 2 Li·2thf] 1 and [(mes) 2 PLi], however, addition of [Cd{N(SiMe 3 ) 2 } 2 ] to the mixture gives the diorganophosphinite complex [{Me 3 - Si) 2 N}Cd{(mes) 2 PO} 2 Li·2thf] 2; the formation of these complexes illustrates t…
The compositional range of ‘Bi4V2O11’ solid solutions containing Na has been determined by means of a phase diagram study using X-ray diffraction and electron probe microanalysis. The locus of the solid solution indicates that Na replaces V in the crystal structure and the BINAVOX family has the overall formula Bi4+yV…
Abstract [MnIIITtBuPP]+[C4(CN)6].‐ · 5PhMe [MnIIITtBuPP = meso‐tetrakis‐(4′‐tert‐butylphenyl)porphinatomanganese(III)] has been prepared and structurally and magnetically characterized. The uniform, linear‐chain (1‐D) coordination polymer comprises alternating cations and anions. The bond lengths in planar ion [C4(CN)…
The system di- tert -butyl nitroxide (DTBN) adsorbed on a thin film of γ-Al 2 O 3 (111) grown on a NiAl(110) single crystal has been studied with various surface science methods, including TPD, XPS, NEXAFS, and ESR line-shapes analysis. In the monolayer regime, two strong chemisorbed species with adsorption energies o…
Novel liquid crystalline oligomesogens, which consist of five, six or eight calamitic 4-cyanobiphenyl, 2-alkyl-5-phenyl-1,3,4-thiadiazole or 5-octyl-2-phenylpyrimidine units covalently linked by spacers of different length with a cyclotribenzylene central core (CTV derivatives, 2,3,7,8,12,13-hexa-substituted 10,15-dih…