Materials Literature
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One-pot high-yield synthesis of the cubane-like complexes [{Mn(µ3-OH)(CO)3}4]1, and mixed-valence [Mn7(µ3-OH)8(CO)182, is reported: 1 and 2 have been characterized via X-ray crystallography, 2 being the largest Mn carbonyl complex yet structurally characterized.
Porphyrin-catalysed epoxidation of alkenes with hydrogen peroxide has been shown to occur in the presence of non-oxidisable ligands and bases whereas previous work has suffered from destruction of base and ligand with concomitant excessive use of oxidant. The advantageous use of adducts of hydrogen peroxide is describ…
MnIII–porphyrin 1, bearing an imidazole axial ligand and a carboxylic group juxtaposed on opposite sides of the porphyrin plane, is an extremely efficient catalyst for the activation of 30% H2O2 in hydrocarbon oxygenations carried out in CH2Cl2–H2O; initial rates at 1 min up to 500 turnovers min–1 at 0 °C in the epoxi…
We report spontaneous Brillouin and photon correlation spectroscopic results on the dynamics of the local density fluctuations in the ionic mixed salt xKNO3⋅yCa(NO3)2 with molar ratios 2:1, 3:2, and 1:1. For these mixtures, the density relaxation function g(t) changes from a stretched exponential (β=0.47) near the gla…
Novel spirobenzopyran derivatives carrying monoazacrown moieties at the 8-position undergo selective complexation of alkali metal ions and thereby isomerization to their corresponding merocyanine form in the dark; the isomerization is enhanced especially by Li+ that is likely to interact with the phenolate anion intra…
Basic science and applications (3 papers). Processable conducting polymers and device applications (2 papers). Oral contributions (2 papers). Basic chemistry and applications (3 papers). Special evening session: The polyanilines: Potential technology based on new chemistry and new properties. From transport properties…
It has been found that amorphous La55Al25Ni20 and La55Al25Cu20 alloys exhibit a distinct glass transition and the temperature span between Tg and Tx, ΔTx(=Tx−Tg) exceeds 50 K. This is the first evidence for the formation of an amorphous phase with ΔTx above 50 K in a metal-metal type system. With the aim of clarifying…
Arylaldehyde and arylketone hydrazones, e.g. 4-diphenylaminobenzaldehyde diphenylhydrazone (DPH), are found to constitute a new class of amorphous molecular materials. They form readily stable amorphous glasses on cooling from the melt. The hole drift mobility of DPH in its glassy state was 2.2 × 10–4 cm2 s–1 V–1 at a…
The mechanical performance of brittle ceramics can be improved by increasing their fracture toughness/resistance. This is reflected by increases in resistance to strength degradation from in-service thermal stresses, slow crack growth, and contact or impact damage when the fracture toughness is enhanced. Furthermore,…
Zinc 1,4,8,11,15,18,22,25-octaalkylphthalocyaninates exhibit discotic mesophase behaviour over a much wider temperature range than their nickel analogues. In the former series a mesophase is exhibited by compounds bearing substituents as short as pentyl groups.
Marine mussels Mytilus edulis accumulate radionuclides of cobalt, zinc, ruthenium, silver and caesium in the soft tissues hnearly over time during exposure periods up to 9 d. Radiotracer binding to shell is rapid, but variable, and is essentially complete after 1 d. The distribution between soft tissues and shell vari…
FTIR spectra are reported of CO adsorbed at 303–573 K on Pt/Al2O3, Rh/Al2O3 and Pt–Rh/Al2O3. Catalysts containing Rh were precalcined at either 673 K or 873 K before reduction in hydrogen and exposure to CO. The intensities of infrared bands due to gem-dicarbonyl and linear carbonyl species were a function of both the…
In this paper, the acid-base interaction in terms of the molecular interaction is discussed from a broader background. Thus, the overall nature of the acid-base interaction consists of electrostatic, charge (or electron) transfer, exchange, polarization, and dispersion components. Among them, the electrostatic (or ion…
Work undertaken to elucidate failures of standard austenitic stainless steels in indoor swimming pool atmospheres which have occurred in recent years in Europe and North America is described. The unusual feature of these failures is that they occurred by a stress corrosion cracking (SCC) mechanism at ambient temperatu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProcessible precursor for boron nitride coatings and matrixesKazimiera J. L. Paciorek, Steven R. Masuda, Reinhold H. Kratzer, and Wayde R. SchmidtCite this: Chem. Mater. 1991, 3, 1, 88–91Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Pu…
The purpose of the research was to find effective ways of improving the chemical durability of phosphate glasses while maintening a thermal expansion coefficient superior to 175.10 -7 °C -1 and retaining other desirable properties which are needed for sealing to low melting, high expansion metals and alloys.The genera…
The batch-type hot-dip Zn and 5%Al-Zn coatings were investigated in the present work for correlations between their corrosion resistance, electrochemical behaviors, and microstructures. The microstructures of the coatings were altered with air cooling and water quenching for studying the corrosion resistance mechanism…
Single-crystal X-ray work has been carried out on crystals containing the 1-methylimidazole adduct of µ-oxo-bis[(phthalocyaninato)iron(III)], [{Fe(pc)(mim)}2O]·[Fe(pc)(mim)2]·3Me2CO. The crystals are monoclinic, space group C2/c, with a= 35.236(5), b= 14.173(2), c= 23.220(3)Å, β= 103.56(10)° and Z= 4. The structure wa…
The ground-state Coulomb energy and zero-point vibrational energy are calculated numerically for the perfect two-dimensional (2D) Wigner crystal and for a 2D Wigner crystal containing interstitials and vacancies. In the limit of large systems, only the vacancy and the interstitial with threefold rotational symmetry ar…
This paper describes the structural (species richness, species diversity, pattern-diversity, biomass, coverage, specific distribution, homogeneity) and functional (production, PIB ratio) changes observed during the annual cyc1es of eight phytobenthic Mediterranean communities by using PCA analysis. The first axis obta…