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961.
Mandal SK Itkis ME Chi X Samanta S Lidsky D Reed RW Oakley RT Tham FS Haddon RC 《Journal of the American Chemical Society》2005,127(22):8185-8196
We report the preparation, crystallization, and solid-state characterization of the first members of a new family of spiro-bis-(1,9-diamino-substituted-phenalenyl)boron neutral radicals. The crystal structures show that the three radicals are monomeric and without close contacts in the crystal lattice. In all cases magnetic susceptibility measurements confirm the presence of free radicals with one unpaired spin per molecule. Two of the new radical compounds are among the most highly conducting neutral organic solids, with room-temperature conductivities reaching sigma(RT) = 4 x 10(-2) S/cm. The measured conductivities correlate with the closest intermolecular contacts in the solid state and with the calculated band dispersions, even though the bandwidths are much smaller than those found in other organic conductors. 相似文献
962.
A novel perfluorinated corrole, 2,3,7,8,12,13,17,18-octafluoro-5,10,15-tris(pentafluorophenyl)corrole, and its manganese(III) and oxomanganese(V) derivatives have been synthesized. The perfluorinated manganese corrolate exhibited excellent reactivity and stability in the catalytic oxidation of alkenes with iodosylbenzene. 相似文献
963.
StructureRefinementofSamariumTritelluridesChiLi-Sheng;DengShui-Quan;ZhuangHong-Hui(StareKeyLaboratoryofStructuralChemistry,Fu... 相似文献
964.
按两种不同的结构类型(中性分子型和离子型)着重对五配位锗化合物的结构特点、研究进展等方面的内容进行了综述。 相似文献
965.
966.
Micelle-hosted palladium nanoparticles catalyze citral molecule hydrogenation in supercritical carbon dioxide 总被引:2,自引:0,他引:2
A new approach of employing metal particles in micelles for the hydrogenation of organic molecules in the presence of fluorinated surfactant and water in supercritical carbon dioxide has very recently been introduced. This is allegedly to deliver many advantages for carrying out catalysis including the use of supercritical carbon dioxide (scCO2) as a greener solvent. Following this preliminary account, the present work aims to provide direct visual evidence on the formation of metal microemulsions and to investigate whether metal located in the soft micellar assemblies could affect reaction selectivity. Synthesis of Pd nanoparticles in perfluorohydrocarboxylate anionic micelles in scCO2 is therefore carried out in a stainless steel batch reactor at 40 degrees C and in a 150 bar CO2/H2 mixture. Homogeneous dispersion of the microemulsion containing Pd nanoparticles in scCO2 is observed through a sapphire window reactor at W0 ratios (molar water-to-surfactant ratios) ranging from 2 to 30. It is also evidenced that the use of micelle assemblies as new metal catalyst nanocarriers could indeed exert a great influence on product selectivity. The hydrogenation of a citral molecule that contains three reducible groups (aldehyde, double bonds at the 2,3-position and the 6,7-position) is studied. An unusually high selectivity toward citronellal (a high regioselectivity toward the reduction of the 2,3-unsaturation) is observed in supercritical carbon dioxide. On the other hand, when the catalysis is carried out in the conventional liquid or vapor phase over the same reaction time, total hydrogenation of the two double bonds is achieved. It is thought that the high kinetic reluctance for double bond hydrogenation of the citral molecule at the hydrophobic end (the 6,7-position) is due to the unique micelle environment that is in close proximity to the metal surface in supercritical carbon dioxide that guides a head-on attack of the molecule toward the core metal particle. 相似文献
967.
Chen X Wiehle S Weygand M Brezesinski G Klenz U Galla HJ Fuchs H Haufe G Chi L 《The journal of physical chemistry. B》2005,109(42):19866-19875
A single-chain fatty acid methyl ester, racemic anti-3-fluoro-2-hydroxyeicosanoic acid methyl ester (beta-FHE), forms an unconventional air-stable interdigitated bilayer at the air-water interface. The interdigitated bilayer transferred onto solid substrate by the Langmuir-Blodgett (LB) technique keeps air-stable without any substrate modification or protein inclusion. There are two visible plateaus in the surface pressure-molecular area (pi-A) isotherms of beta-FHE Langmuir film during continuous compression. According to Brewster angle microscopy (BAM), grazing incidence X-ray diffraction (GIXD), X-ray reflectivity (XR), fluorescence microscopy (FM), and atomic force microscopy (AFM) measurements, the first plateau is attributed to the coexistence of liquid expanded (LE) and liquid condensed (LC) phases in the monolayer, while the second plateau is interpreted as the transition from LC monolayer to interdigitated bilayer. The coupling between tilt and curvature associated with the packing mismatch between headgroup and chain gives rise to buckling and folding of the monolayer, leading to the transition of the LC monolayer to a bilayer structure. The diffusion-limited aggregation (DLA) model is applied to describe the formation of the fractal structures of the bilayer as observed in the second plateau. In addition, the transition between monolayer and bilayer is reversible. The present works are interesting for understanding biological processes, for example, the behavior of lung surfactants. 相似文献
968.
Eng‐Chi Wang Keng‐Shiang Huang Hsing‐Ming Chen Chung‐Chin Wu Gwo‐Jiun Lin 《中国化学会会志》2004,51(3):619-627
A new and highly efficient method for the conversion of aldoximes to nitriles was established. By fusing with phthalic anhydride, aldoximes were efficiently and smoothly converted into nitriles, in high yields (over 85%) and in a short time (within 5 minutes). The mixture of phthalic anhydride, a cyclic anhydride, and aldoximes in fusing state set up an ideal transition state for a selective [3.3]‐sigmatropic rearrangement of the acylated aldoximes to nitriles. 相似文献
969.
Zheng Bo Jian Hua Yan Xiao Dong Li Yong Chi Bruno Chéron Ke Fa Cen 《Plasma Chemistry and Plasma Processing》2007,27(6):691-700
The dependence of gliding arc gas discharge characteristics, including gas flow field, arc column motion and volatile organic
compounds (VOCs) decomposition performance, on reactor configuration parameters was investigated based on numerical simulation
and laboratory experimental findings. For a given supply voltage (10 kV) and a certain nozzle outlet diameter (1.5 mm), increasing
the electrodes gap (1–4 mm) or decreasing vertical distance between electrode throat and nozzle outlet (25–10 mm) will increase
the gas flow rate through the electrode throat, the gas velocity in the plasma region, the arc column velocity, the maximum
attainable position of the arc column and the electrical power consumption, also, higher VOCs decomposition rate and lower
specific energy requirement are observed according to the n-butane and toluene decomposition experiments. 相似文献
970.
Solid poly(methyl vinyl-alt-maleimide), when subjected to heating at 100°C while being vacuum pumped at 0.1 mm Hg pressure, was converted to a copolymer in which a substantial portion of the imide groups were converted to anhydride groups. Similarly, heating at 100°C at atmospheric pressure in a circulating air oven brought about the same reaction but at a faster rate. This confirms the hypothesis that the formation of maleic anhydride comonomer units from poly(methyl vinyl ether-alt-ammonium maleamate) not only proceeds directly by ring closure of amic acid formed by loss of ammonia but probably also includes, as a parallel pathway, hydrolysis by atmospheric moisture of maleimide comonomer units. 相似文献