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Kovalenko M.V.,Institute of Inorganic Chemistry | Kovalenko M.V.,Empa - Swiss Federal Laboratories for Materials Science and Technology
Chimia | Year: 2013

This account highlights our recent and present activities dedicated to chemical synthesis and applications of inorganic nanostructures. In particular, we discuss the potential of metal amides as precursors in the synthesis of metallic and semiconductor nanocrystals. We show the importance of surface chemical functionalization for the emergence of collective electronic properties in nanocrystal solids. We also demonstrate a new kind of long-range ordered, crystalline matter comprising colloidal nanocrystals and atomically defined inorganic clusters. Finally, we point the reader's attention to the high potential benefits of size- and shapetunability of nanocrystals for achieving higher performance of rechargeable Li-ion battery electrodes. © Schweizerische Chemische Gesellschaft.

Widenmeyer M.,University of Stuttgart | Niewa R.,University of Stuttgart | Hansen T.C.,Laue Langevin Institute | Kohlmann H.,Institute of Inorganic Chemistry
Zeitschrift fur Anorganische und Allgemeine Chemie | Year: 2013

In order to perform real-time studies of solid-gas reactions involving light elements such as hydrogen and nitrogen, gas pressure and gas flow cells were developed for in situ neutron powder diffraction. The gas pressure cell is based on a sapphire single crystal tube as a sample holder and provides high quality diffraction patterns with very low background up to 16.0 MPa hydrogen (deuterium) gas pressure and temperatures up to 400 °C. The gas flow cell contains a silica tube as sample container and is optimized for flowing ammonia as reaction gas. While it produces higher background owing to the silica, it allows much higher temperatures of up to 750 °C to be used. For both cells heating is realized contactless and without any contribution to the diffraction patterns by two lasers and so high-quality diffraction data allowing for a detailed Rietveld analysis can be collected on D20 (Institute Laue-Langevin) with a one minute time resolution. Examples are presented demonstrating the potential of the in situ gas cells, ranging from the nitridation of vanadium and iron powders with flowing ammonia, to the deuteration of palladium and the hydrogen storage material LaNi5. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Manolov I.,Medical University-Sofia | Maichle-Moessmer C.,Institute of Inorganic Chemistry
X-ray Structure Analysis Online | Year: 2012

AbsstractThe structure of 3,3'-[(4-benzyloxyphenyl)methylene]bis-(4-hydroxy-2H-chromen-2-one) was determined by X-ray crystallography The compound crystallized in a monoclinic system and was characterized thus: P2 1/n, a = 12.2990(15)Å, b = 10.8108(8)Å, c = 21.277(2)Å, Z = 4, V = 2787.7(5)Å 3. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F2 to final values of R1 = 0.0860 and R2 = 0.1436. 2012 © The Japan Society for Analytical Chemistry.

Marthala V.R.R.,University of Stuttgart | Hunger M.,University of Stuttgart | Kettner F.,Institute of Inorganic Chemistry | Krautscheid H.,Institute of Inorganic Chemistry | And 3 more authors.
Chemistry of Materials | Year: 2011

Large crystals of all-silica, aluminum-, and boron-containing ferrierite zeolites were synthesized using a solvothermal synthesis method and a fluoride medium. Alkylamines, namely, propylamine, butylamine, and pentylamine were employed as templates in the syntheses. The products were characterized by powder X-ray diffraction (XRD), inductively coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), elemental (CHN) analyses, scanning electron microscopy (SEM), N2-adsorption, and 1H, 11B, 27Al, as well as 29Si MAS NMR spectroscopy. The 27Al and 11B MAS NMR spectroscopic investigations revealed that aluminum and boron were successfully incorporated into the FER-type framework. SEM indicated the occurrence of crystals with a size of up to about 600 μm. Furthermore, for all-silica and boron-containing ferrierite zeolites, the shape, size, and thickness of the crystals could be controlled by increasing the chain length of the alkyl group in the alkylamine and the crystallization time. Aluminum-containing ferrierite zeolites could be synthesized with a rectangular morphology exclusively. Observation of transient guest profiles during methanol uptake by means of IR microscopy exemplifies the possibility of directly observing diffusion anisotropy in FER-type frameworks. © 2011 American Chemical Society.

Koppenol W.H.,Institute of Inorganic Chemistry | Stanbury D.M.,Auburn University | Bounds P.L.,Institute of Inorganic Chemistry
Free Radical Biology and Medicine | Year: 2010

We use published Gibbs energies of formation and equilibrium constants to determine electrode potentials for the partially reduced intermediates along the pathway of reduction of dioxygen to water, as well as of ozone and singlet dioxygen. The results are summarized in an oxidation state (Frost) diagram. Our review of the literature on electrode potentials leads us to revise values for the O2/O2•- couple to E°(O2g/O2•-)=-0.35±0.02V and E°(O2aq/O2•-)=-0.18±0.02V from -0.33 and -0.16V, respectively. Other electrode potentials (pH 7) for the radical species covered are E°′(O3g/O3•-)=+0.91V, E°′(HO2•, H+/H2O2)=+1.05V, E°′(H2O2, H+/HO•, H2O)=+0.39V, and E°′(HO•, H+/H2O)=+2.31V. © 2010 Elsevier Inc.

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