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951.
In the title compound, [Fe(C5H5)(C16H12N3OS)], the 8‐am­inoquinoline and acyl­thio­urea moieties are almost planar. There are two perpendicular arrangements of the mol­ecules in the crystal with slightly different conformations. The two cyclo­penta­dienyl rings in each mol­ecule are parallel and eclipsed.  相似文献   
952.
二氧化钛分子电致发光激发特性研究   总被引:1,自引:0,他引:1  
采用密度泛函B3P86方法优化得到了沿分子平面不同外电场作用下TiO2分子的基态稳定构型, 在优化构型下利用杂化CIS (CI-Singles)-B3P86方法在6-311+G*基组水平上, 研究了不同外电场下TiO2分子前六个激发态的激发能和跃迁波长等激发特性. 研究结果表明, TiO2分子多个激发态满足偶极跃迁定则, 跃迁光谱对应多个峰值, 在分子水平上, 可以增大利用太阳光的比例. 在外电场作用下, 能隙随电场的增大而减小, 电子易从最高占据轨道跃迁到最低空轨道形成空穴, 各个激发态跃迁波长均有随电场增大发生红移的趋势, 最长589 nm, 因而利用外电场可以控制材料的发光光谱范围在可见光区域扩展.  相似文献   
953.
The long‐standing challenge associated with capacity fading of spinel LiMn2O4 cathode material for lithium‐ion batteries is investigated. Single‐crystalline spinel LiMn2O4 nanorods were successfully synthesized by a template‐engaged method. Porous Mn3O4 nanorods were used as self‐sacrificial templates, into which LiOH was infiltrated by a vacuum‐assisted impregnation route. When used as cathode materials for lithium‐ion batteries, the spinel LiMn2O4 nanorods exhibited superior long cycle life owing to the one‐dimensional nanorod structure, single‐crystallinity, and Li‐rich effect. LiMn2O4 nanorods retained 95.6 % of the initial capacity after 1000 cycles at 3C rate. In particular, the nanorod morphology of the spinel LiMn2O4 was well‐preserved after a long‐term cycling, suggesting the ultrahigh structural stability of the single crystalline spinel LiMn2O4 nanorods. This result shows the promising applications of single‐crystalline spinel LiMn2O4 nanorods as cathode materials for lithium‐ion batteries with high rate capability and long cycle life.  相似文献   
954.
Reactions of three tetrazole containing carboxylic acid ligands, namely, Hpztza, Htzpya, and Hpytza [Hpztza = 5‐(2‐pyrazinyl)tetrazole‐2‐acetic acid, Htzpya = 3‐(5‐tetrazolyl)pyridine‐1‐acetic acid, Hpytza = 5‐(3‐pyridyl)tetrazole‐2‐acetic acid] with NdCl3 · 6H2O under hydrothermal conditions, afforded the complexes [Nd(pztza)2(H2O)6] · pztza · 3H2O ( 1 ), [Nd2(tzpya)2(H2O)12]Cl4 · 2H2O ( 2 ), and [Nd(pytza)2Cl(H2O)2] ( 3 ). The compounds were structurally characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. X‐ray diffraction analyses revealed that compound 1 displays a mononuclear structure, 2 shows a dinuclear structure, and 3 features a 1D polymeric chain structure via pytza as linker. Furthermore, the luminescent properties investigated at room temperature in the solid state show that compound 2 has an obvious decrease in its luminescence, when compared to the ligand.  相似文献   
955.
A novel, Cu(OAc)2/TEMPO promoted one‐step approach for the preparation of fully substituted pyrimidines from readily available amino acid esters has been described. In this reaction, the amino acid esters act as the only N?C sources for the construction of corresponding pyrimidines. The mechanism of this process includes oxidative dehydrogenation, the generation of an imine radical, and a formal [3+3] cycloaddition. This methodology proves to be a high atom‐economic and straightforward strategy for the synthesis of pyrimidines and diverse substrates which are substituted by various functional groups have been afforded in moderate to good yield.  相似文献   
956.
957.
Oxygen species on fresh and treated NiO/Al2O3 and their activities for oxidation of ethane and ethylene were investigated using catalytic property measurements, ethane and ethylene pulse experiments and O2–TPD–MS experiments. The results revealed that there are two kinds of active oxygen species (the more active one and the less active one) on fresh NiO/Al2O3 catalyst, but there is only one active oxygen species, the less active one, on treated NiO/Al2O3 catalyst. The more active oxygen species can convert ethane or ethylene to carbon dioxide by one step while the less active one can only convert ethane to ethylene, but cannot convert ethane and/or ethylene to carbon dioxide. The more active oxygen species can be removed from the catalyst by heating from 350 to 850 °C. The amounts of desorption oxygen on the catalysts are proportional to their selectivity to carbon dioxide.  相似文献   
958.
A kind of aziridine crosslinkers was synthesized and used to crosslink acrylate copolymers. The crosslinkingproperties and curing kinetics of the resin were studied. It was found that with the increase of the content of crosslinker in theemulsion, the mechanical properties and solvent resistance of the resin will be apparently improved, but its glass transitiontemperature (T_g) is very low. The lowest amount of crosslinker used in the acrylic resin emulsion is 0.25%. Curing kineticsstudied by DSC show that this curing reaction occurs readily because the apparent activation energy of the reaction is low(65.1 kJ/mol). These results demonstrate that the aziridine crosslinker is indeed a low temperature crosslinking agent and canbe used at room temperature.  相似文献   
959.
The bridged tri-imidazoliums 3.3X^--5.3X^-(X^-=PF6^-,Br^-,I^-)and bis-imidazoliums 6.2PF6^- were synthesized by N-quaternization of imidazole derivative 1 in acetonitrile under reflux.UV spectroscopic titration experiments showed that the halide salts and hexafluorophosphate salts of these imidazoliums exhibited good recognition toward anions in water and in acetonitrile,respectively.  相似文献   
960.
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