Materials Literature
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The temperature influence on the thermal degradation products evolved from poly(ethylene terephthalate) (PET) was investigated. The experiments were carried out within the temperature range of 200–700°C in air. The main volatile toxic products and weight losses during thermal degradation of PET were determined. The re…
A ruthenium complex of meso-tetrakis(2,6-dichlorophenyl)porphyrin, [Ru(II)(TDCPP)(CO)(EtOH)], is immobilized into mesoporous MCM-41 molecular sieves; the supported Ru catalyst can effect highly selective heterogeneous alkene epoxidations using 2,6-dichloropyridine N-oxide as terminal oxidant. Aromatic and aliphatic al…
The heteropolyanion [PW 11 O 39 RhCl] 5- ( 1-Cl ) was synthesized by hydrothermal reaction of [PW 11 O 39 ] 7- and RhCl 3 at 150 °C for 20 h. The tetramethylammonium salt of 1-Cl was characterized by elemental analysis, 31 P and 183 W NMR, and solution molecular weight determination by ultracentrifugation (found 2744…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTRhodium−Carbon Bond Formation in Aqueous Solution. Synthesis, Structure, and Reactivity of the Functionalized Heteropolytungstates, [XW11O39RhCH2COOH]5,6- (X = P, Si)Xinyi Wei, Michael H. Dickman, and Michael T. PopeView Author Information Department of Chemistry, Box…
Dielectric, gravimetric, dynamic mechanical, and infrared measurements are reported on the effect of different stoichiometric ratios on the water absorption of diglycidyl ether of bisphenol A (DGEBA), MY720 (Ciba Geigy) cured with stoichiometric variations of triethylenetetramine (TETA), (BDH). Resin samples were prep…
The adsorption of humic acid onto chitin and chitosan has been investigated. The uptake of humic acid from aqueous solution was determined from changes in concentration, as measured by ultraviolet-visible spectroscopy. The decrease in humic acid removal was observed with the increase in pH. A significant uptake of hum…
A series of 5,15-diphenylporphyrinatonickel(II) derivatives containing electron-releasing (Me(2)NC(6)H(4)C&tbd1;C-) and -withdrawing groups [-CHO, -CH=C(CN)(2), -CH=C(CO(2)Et)(2), -CH=CHCHO] in opposite meso positions has been synthesized through the classical formylation, halogenation, Knoevenagel condensation, and p…
Tungsten oxide−zirconia catalysts were prepared by drying powdered Zr(OH) 4 with ammonium metatungstate aqueous solution, followed by calcining in air at high temperature. Characterization of prepared catalysts was performed by using Fourier transform infrared (FTIR), Raman, and X-ray photoelectron spectroscopy (XPS),…
Peptide-amphiphiles with collagen-model head groups and dialkyl chain tails have been shown previously to self-assemble into highly ordered polyPro II-like triple-helical structures when dissolved in aqueous subphases. In the present study, we have examined peptide-amphiphiles containing monoalkyl chain tails for simi…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDendrimers Containing Chiral Ferrocenyl Diphosphine Ligands for Asymmetric CatalysisChristoph Köllner, Benoît Pugin, and Antonio TogniView Author Information Laboratory of Inorganic Chemistry Swiss Federal Institute of Technology ETH-Zentrum, CH-8092 Zürich, Switzerlan…
The thermal and mechanical properties for four binary blends, high-density polyethylene (HDPE)–metallocene polyethylene (MCPE), polypropylene (PP)–MCPE, poly(propylene-co-ethylene) (CoPP)–MCPE, and poly(propylene-co-ethylene-co-1-butene) (TerPP)–MCPE were investigated to compare the compatibility and molecular microme…
Manganites with the perovskite structure represent a very important family of oxides which are extensively studied for their colossal magnetoresistance (CMR) properties. In the present review we discuss the different factors which govern the magnetic and transport properties of these materials: carrier concentration,…
Light-harvesting arrays containing one, two, or eight boron-dipyrrin (BDPY) pigments and one porphyrin (free base or Zn chelate) have been synthesized using a modular building block approach. The reaction of pyrrole and 4-(BDPY)benzaldehyde or 3,5-bis(BDPY)benzaldehyde, prepared by Pd-mediated ethynylation with the co…
Without any prior knowledge of the molecular structure, all 31 carbon and oxygen atoms of fluorescein diacetate were accurately located based on a high-resolution powder diffraction experiment. Direct methods and Fourier recycling were used. This represents a considerable advance with respect to the size of an organic…
The formation of a sitting-atop (SAT) complex of Cu(II) ion with 5,10,15,20-tetraphenylporphyrin (H(2)tpp) in acetonitrile has been observed, and the kinetic parameters for the formation were determined as follows: k(S0) = (3.6 +/- 0.1) x 10(5) mol(-)(1) dm(3) s(-)(1) at 25.0 degrees C, DeltaH(S0)() = 56 +/- 5 kJ mol(…
Double chelate coordination of [Cu(Ph3P)2]+ stabilizes the radical anion of 2,2′-azobis(5-chloropyrimidine), which exhibits a N–N bond length of 1.345(7) Å in the complex (see picture). This is consistent with a one-electron reduced azo functionality.
The introduction of different metal ions in specific positions is achieved in the synthesis of [2×2] grid-type heterometallic complexes (see schematic representation; the black bars symbolize the ditopic ligands, and the circles the different metals ions). This novel method for the construction of inorganic architectu…
Twenty-one components self-assemble to form the large (ca. 25 nm2), planar porphyrin arrays of type 1: four dipyridylporphyrins, four tripyridylporphyrins, one tetrapyridylporphyrin, and twelve PdCl2 units.
We give a simple demonstration of the formula relating the glass transition temperature, $T_g$, to the molar concentration $x$ of a modifier in two types of glasses: binary glasses, whose composition can be denoted by $X_nY_m+xM_pY_q$, with ^$X$ an element of III-rd or IV-th group (e.g. B, or Si, Ge), while $M_pY_q$ i…
Brownian motion of an array of harmonically coupled particles subject to a periodic substrate potential and driven by an external bias is investigated. In the linear response limit (small bias), the coupling between particles may enhance the diffusion process, depending on the competition between the harmonic chain an…