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排序方式: 共有841条查询结果,搜索用时 15 毫秒
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Jan P. Weyrauch Dr. A. Stephen K. Hashmi Prof. Dr. Andreas Schuster Dipl.‐Chem. Tobias Hengst Dipl.‐Chem. Stefanie Schetter Anna Littmann Dipl.‐Chem. Matthias Rudolph Dr. Melissa Hamzic Dr. Jorge Visus Jan W. Bats Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(3):956-963
The substrate scope, the mechanistic aspects of the gold‐catalyzed oxazole synthesis, and substrates with different aliphatic, aromatic, and functional groups in the side chain were investigated. Even molecules with several propargyl amide groups could easily be converted, delivering di‐ and trioxazoles with interesting optical properties. Furthermore, the scope of the gold(I)‐catalyzed alkylidene synthesis was investigated. Further functionalizations of these isolable intermediates of the oxazole synthesis were developed and chelate ligands can be obtained. The use of Barluenga’s reagent offers a new and mild access to the synthetically valuable iodoalkylideneoxazoles from propargylic amides, this reagent being superior to other sources of halogens. 相似文献
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Stability and Conversion of Tin Zintl Anions in Liquid Ammonia Investigated by NMR Spectroscopy
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Franziska Fendt Dr. Carina Koch Dr. Maria Neumeier Dr. Stefanie Gärtner Prof. Dr. Ruth M. Gschwind Prof. Dr. Nikolaus Korber 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14539-14544
Homoatomic polyanions of post‐transition main‐group metals, namely, Zintl anions, are precast in analogous Zintl phases and can react in solution to form new materials. Despite comprehensible reaction approaches, the formed products cannot be planned in advance, as hitherto undetected and therefore disregarded side reactions take place. The outcomes and interpretations of the reactions of Zintl anions are so far based mainly on crystal structures, which only allow characterization of the product that has the lowest solubility. Here we present the results of our investigation of the stability of highly charged tin Zintl anions in liquid ammonia, which is not exclusively based on solution effects but also on the oxidative influence of the solvent. This allows for a deeper understanding of the ongoing processes in solution and opens doors to the directed synthesis of transition metal complexes of Sn44?, here shown by its reactivity towards MesCu. 相似文献
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Very Facile Polarity Umpolung and Noncovalent Functionalization of Inorganic Nanoparticles: A Tool Kit for Supramolecular Materials Chemistry
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Lukas Zeininger Stefanie Petzi Jörg Schönamsgruber Luis Portilla Prof. Dr. Marcus Halik Prof. Dr. Andreas Hirsch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):14030-14035
The facile assembly of shell‐by‐shell (SbS)‐coated nanoparticles [TiO2?PAC16]@shell 1 – 7 (PAC16=hexadecylphosphonic acid), which are soluble in water and can be isolated as stable solids, is reported. In these functional architectures, an umpolung of dispersibility (organic apolar versus water) was accomplished by the noncovalent binding of ligands 1 – 7 to titania nanoparticles [TiO2?PAC16] containing a first covalent coating with PAC16. Ligands 1 – 7 are amphiphilic and form the outer second shell of [TiO2?PAC16]@shell 1 – 7 . The tailor‐designed dendritic building blocks 3 – 5 contain negative and positive charges in the same molecule, and ligands 6 and 7 contain a perylenetetracarboxylic acid dimide (PDI) core ( 6 / 7 ) as a photoactive reporter component. In the redox and photoactive system [TiO2?PAC16]@shell 7 , electronic communication between the inorganic core to the PDI ligands was observed. 相似文献
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This work is concerned with the development of an efficient two-scale numerical scheme for the prediction of the local and effective mechanical response of heterogeneous materials with non-linear constitutive behavior. In order to ensure both, accurate micromechanical fields and feasible overall CPU-times, an efficient but rather simple solution scheme is proposed. Its capabilities are demonstrated using the FE-FFT method [2,3] for the solution of simple two-scale problems. As an example, two-dimensional polycrystalline microstructures with an elasto-viscoplastic constitutive law are considered. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献