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排序方式: 共有165条查询结果,搜索用时 31 毫秒
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Najoua Ouerfelli Daniele Mazza Mohamed Faouzi Zid 《Journal of solid state chemistry》2007,180(4):1224-1229
A new solid solution TlFe0.22Al0.78As2O7 has been synthesized by a solid-state reaction. The structure of the title compound has been determined from a single-crystal X-ray diffraction and refined to final values of the reliability factors: R(F2)=0.030 and wR(F2)=0.081 for 1343 independent reflections with I>2σ(I). It crystallizes in the triclinic space group P-1, with a=6.296(2) Å, b=6.397(2) Å, c=8.242(2) Å, α=96.74(2)°, β=103.78(2)°, γ=102.99(3)°, V=309.0(2) Å3 and Z=2. The structure can be described as a three-dimensional framework containing (Fe/Al)O6 octahedra connected through As2O7 groups. The metallic units and diarsenate groups share oxygen corners to form a three-dimensional framework with interconnected tunnels parallel to the a, b and c directions, where Tl+ cations are located. The ionic conductivity measurements are performed on pellets of the polycrystalline powder. At 683 K, The conductivity value is 5.23×10−6 S cm−1 and the ionic jump activation energy is 0.656 eV. The bond valence analysis reveals that the ionic conductivity is ensured by Tl+ along the [001] direction. 相似文献
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Mariem Ghali Chaima Brahmi Mahmoud Benltifa Cyril Vaulot Aissam Airoudj Philippe Fioux Frédéric Dumur Corine Simonnet-Jégat Fabrice Morlet-Savary Salah Jellali Latifa Bousselmi Jacques Lalevée 《Journal of polymer science. Part A, Polymer chemistry》2021,59(2):153-169
Different inorganic/organic photocomposites based on polyoxometalate (POM) nanoparticles have been developed for photocatalytic applications. Currently, polyoxometalate nanoparticles have been successfully in-situ embedded into an acrylate polymer network by photopolymerization upon mild visible light irradiation at 405 nm. The proposed POM/polymer photocomposites have been characterized using complementary techniques for a better understanding of their photocatalytic activity. Interestingly, the obtained photocomposites exhibit high rigidity, excellent thermal stability, a non-negligible porosity and new functionalities such as light reactivity and redox properties. Moreover, developed composites showed efficient catalytic activity for the color removal of aqueous solutions of erythrosine and rose Bengal under Light Emitting Diodes LED@375 nm irradiation reaching 80 and 90% as a final color removal, respectively. 相似文献
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Latifa Latrous Jeanine Tortajada Violette Haldys Emmanuelle Léon Catarina Correia Jean‐Yves Salpin 《Journal of mass spectrometry : JMS》2013,48(7):795-806
Gas‐phase interactions of organotins with glycine have been studied by combining mass spectrometry experiments and quantum calculations. Positive‐ion electrospray spectra show that the interaction of di‐ and tri‐organotins with glycine results in the formation of [(R)2Sn(Gly)‐H]+and [(R)3Sn(Gly)]+ ions, respectively. Di‐organotin complexes appear much more reactive than those involving tri‐organotins. (MS/MS) spectra of the [(R)3Sn(Gly)]+ ions are indeed simple and only show elimination of intact glycine, generating the [(R)3Sn]+ carbocation. On the other hand, MS/MS spectra of [(R)2Sn(Gly)‐H]+complexes are characterized by numerous fragmentation processes. Six of them, associated with elimination of H2O, CO, H2O + CO and formation of [(R)2SnOH]+ (?57 u),[(R)2SnNH2]+( ?58 u) and [(R)2SnH]+ (?73 u), are systematically observed. Use of labeled glycines notably concludes that the hydrogen atoms eliminated in water and H2O + CO are labile hydrogens. A similar conclusion can be made for hydrogens of [(R2)SnOH]+and [(R2)SnNH2]+ions. Interestingly, formation [(R)2SnH]+ ions is characterized by a migration of one the α hydrogen of glycine onto the metallic center. Finally, several dissociation routes are observed and are characteristic of a given organic substituent. Calculations indicated that the interaction between organotins and glycine is mostly electrostatic. For [(R)2Sn(Gly)‐H]+complexes, a preferable bidentate interaction of the type η2‐O,NH2 is observed, similar to that encountered for other metal ions. [(R)3Sn]+ ions strongly stabilize the zwitterionic form of glycine, which is practically degenerate with respect to neutral glycine. In addition, the interconversion between both forms is almost barrierless. Suitable mechanisms are proposed in order to account for the most relevant fragmentation processes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Amel Souibgui Anne Gaucher Jérôme Marrot Flavien Bourdreux Faouzi Aloui Béchir Ben Hassine Damien Prim 《Tetrahedron》2014
New series of acridines and phenanthrolines have been prepared from β-chlorovinyl aldehydes and various aniline derivatives allowing the installation of valuable substituents, such as ketone, nitro or amino groups at the heterocyclic core. X-ray analyses confirmed the structures of acridines and phenanthrolines as well as the presence of partially hydrogenated rings and their crucial impact on the overall shape of the acridine-based architectures. 1H NMR revealed the helical behaviour of several acridine motives. Comparison of UV data between architectures and influence of number of partially hydrogenated rings is also described. 相似文献
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NaAgPbP2O7 was prepared with a solid-state reaction. The electrical properties were investigated by using impedance measurements in
the frequency range from 200 Hz to 5 MHz with the TEGAM 3550 ALF automatic bridge monitored by a microcomputer between 581 K
and 703 K. The Z′ and Z″ versus frequency plots are well fitted to an equivalent circuit model. The conductivity data obey the universal power law.
The conductivity in the material is due to the hopping of monovalent ions parallel to (001) plane. 相似文献