Home About us Contact
|
Home About us Contact | ||
|
|
||
Materials Chemistry (material + chemistry)
Selected AbstractsFacile Access to Optically Active Ferrocenyl Derivatives with Direct Substitution of the Hydroxy Group Catalyzed by Indium TribromideEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2007Paola Vicennati Abstract Ferrocene derivatives have found many different uses and applications in organometallic chemistry, material chemistry, and catalysis. We have shown that using a catalytic amount (5,10 mol-%) of commercially available indium tribromide, at room temperature, many carbon nucleophiles, such as indoles, allylsilane, enolsilane, silyl ketene acetal, diketone, and trimethylsilylcyanide, smoothly react with different optically active ferrocenyl alcohol derivatives to afford the desired products in high yield, with retention of configuration. Also, many different N-nucleophiles (azide, carbamates) and O-nucleophiles (alcohols) react as well, again with retention of configuration. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] UV photosynthesis of nickel carbonylAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2004Xuming Guo Abstract In the presence of low-molecular-weight organic acids, such as formic, acetic, and propionic, inorganic nickel salts in aqueous solutions are converted to the volatile tetracarbonyl by UV irradiation. Experiments were performed using a flow-through photoreactor, consisting of a 6 m length polytetrafluoroethylene tubing wrapped around a low-pressure mercury vapor UV lamp (254 nm, 15 W). The efficiency of transformation was estimated to be 95%. As no carbon monoxide or external reductant is required, photochemical synthesis may prove to be useful in material chemistry and applicable to the extractive metallurgy of nickel, as well as its refining and recycling. Copyright © 2004 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source] Development and Testing of Energetic Materials: The Concept of High Densities Based on the Trinitroethyl FunctionalityADVANCED FUNCTIONAL MATERIALS, Issue 3 2009Michael Göbel Abstract The development of new energetic materials is an emerging area of materials chemistry facilitated by a worldwide need to replace materials used at present, due to environmental considerations and safety requirements, while at the same time securing high performance. The development of such materials is complex, owing to the fact that several different and apparently mutually exclusive material properties have to be met in order for a new material to become widely accepted. In turn, understanding the basic principles of structure property relationships is highly desirable, as such an understanding would allow for a more rational design process to yield the desired properties. This article covers the trinitroethyl functionality and its potential for the design of next generation energetic materials, and describes relevant aspects of energetic materials chemistry including theoretical calculations capable of reliably predicting material properties. The synthesis, characterization, energetic properties, and structure property relationships of several new promising compounds displaying excellent material properties are reported with respect to different kinds of applications and compared to standard explosives currently used. Based on a review of trinitroethyl-containing compounds available in the literature, as well as this new contribution, it is observed that high density can generally be obtained in a more targeted manner in energetic materials taking advantage of noncovalent bonding interactions, a prerequisite for the design of next generation energetic materials. [source] Preparation of Inorganic Materials Using Ionic LiquidsADVANCED MATERIALS, Issue 2 2010Zhen Ma Abstract Conventional synthesis of inorganic materials relies heavily on water and organic solvents. Alternatively, the synthesis of inorganic materials using, or in the presence of, ionic liquids represents a burgeoning direction in materials chemistry. Use of ionic liquids in solvent extraction and organic catalysis has been extensively studied, but their use in inorganic synthesis has just begun. Ionic liquids are a family of non-conventional molten salts that can act as templates and precursors to inorganic materials, as well as solvents. They offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, tunable solubility for both organic and inorganic molecules, and much synthetic flexibility. In this Review, the use of ionic liquids in the preparation of several categories of inorganic and hybrid materials (i.e., metal structures, non-metal elements, silicas, organosilicas, metal oxides, metal chalcogenides, metal salts, open-framework structures, ionic liquid-functionalized materials, and supported ionic liquids) is summarized. The status quo of the research field is assessed, and some future perspectives are furnished. [source] Metal Chalcogenide Clusters on the Border between Molecules and Materials,ADVANCED MATERIALS, Issue 18 2009John F. Corrigan Abstract The preparative and materials chemistry of high nuclearity transition metal chalcogenide nanoclusters has been in the focus of our research for many years. These polynuclear metal compounds possess rich photophysical properties and can be understood as intermediates between mononuclear complexes and binary bulk phases. Based on our previous results we discuss herein recent advances in three different areas of cluster research. In the field of copper selenide clusters we present the synthesis of monodisperse, nanostructured , -Cu2Se via the thermolysis of well-defined cluster compounds as well as our approaches in the synthesis of functionalized clusters. In case of silver chalcogenides we established a strategy to synthesis cluster compounds containing several hundreds of silver atoms with the nanoclusters arranging in a closely packed crystal lattice. Finally the presented chalcogenide clusters of the group 12 metals (Zn, Cd, Hg) can be taken as model compounds for corresponding nanoparticles as even the smallest of frameworks display a clear structural relationship to the bulk materials. [source] Speciation of Rare-Earth Metal Complexes in Ionic Liquids: A Multiple-Technique ApproachCHEMISTRY - A EUROPEAN JOURNAL, Issue 6 2009Peter Nockemann Dr. Abstract The dissolution process of metal complexes in ionic liquids was investigated by a multiple-technique approach to reveal the solvate species of the metal in solution. The task-specific ionic liquid betainium bis(trifluoromethylsulfonyl)imide ([Hbet][Tf2N]) is able to dissolve stoichiometric amounts of the oxides of the rare-earth elements. The crystal structures of the compounds [Eu2(bet)8(H2O)4][Tf2N]6, [Eu2(bet)8(H2O)2][Tf2N]6,2H2O, and [Y2(bet)6(H2O)4][Tf2N]6 were found to consist of dimers. These rare-earth complexes are well soluble in the ionic liquids [Hbet][Tf2N] and [C4mim][Tf2N] (C4mim=1-butyl-3-methylimidazolium). The speciation of the metal complexes after dissolution in these ionic liquids was investigated by luminescence spectroscopy, 1H, 13C, and 89Y,NMR spectroscopy, and by the synchrotron techniques EXAFS (extended X-ray absorption fine structure) and HEXS (high-energy X-ray scattering). The combination of these complementary analytical techniques reveals that the cationic dimers decompose into monomers after dissolution of the complexes in the ionic liquids. Deeper insight into the solution processes of metal compounds is desirable for applications of ionic liquids in the field of electrochemistry, catalysis, and materials chemistry. [source] | |||||||||||||