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981.
Bing Ding Dr. Changzhou Yuan Laifa Shen Guiyin Xu Ping Nie Prof. Xiaogang Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):1013-1019
A three‐dimensional (3D) hierarchical carbon–sulfur nanocomposite that is useful as a high‐performance cathode for rechargeable lithium–sulfur batteries is reported. The 3D hierarchically ordered porous carbon (HOPC) with mesoporous walls and interconnected macropores was prepared by in situ self‐assembly of colloidal polymer and silica spheres with sucrose as the carbon source. The obtained porous carbon possesses a large specific surface area and pore volume with narrow mesopore size distribution, and acts as a host and conducting framework to contain highly dispersed elemental sulfur. Electrochemical tests reveal that the HOPC/S nanocomposite with well‐defined nanostructure delivers a high initial specific capacity up to 1193 mAh g?1 and a stable capacity of 884 mAh g?1 after 50 cycles at 0.1 C. In addition, the HOPC/S nanocomposite exhibits high reversible capacity at high rates. The excellent electrochemical performance is attributed exclusively to the beneficial integration of the mesopores for the electrochemical reaction and macropores for ion transport. The mesoporous walls of the HOPC act as solvent‐restricted reactors for the redox reaction of sulfur and aid in suppressing the diffusion of polysulfide species into the electrolyte. The “open” ordered interconnected macropores and windows facilitate transportation of electrolyte and solvated lithium ions during the charge/discharge process. These results show that nanostructured carbon with hierarchical pore distribution could be a promising scaffold for encapsulating sulfur to approach high specific capacity and energy density with long cycling performance. 相似文献
982.
Dr. Jiwei Liu Junjie Xu Prof. Renchao Che Huajun Chen Mengmei Liu Zhengwang Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(21):6746-6752
A facile and efficient strategy for the synthesis of hierarchical yolk–shell microspheres with magnetic Fe3O4 cores and dielectric TiO2 shells has been developed. Various Fe3O4@TiO2 yolk–shell microspheres with different core sizes, interstitial void volumes, and shell thicknesses have been successfully synthesized by controlling the synthetic parameters. Moreover, the microwave absorption properties of these yolk–shell microspheres, such as the complex permittivity and permeability, were investigated. The electromagnetic data demonstrate that the as‐synthesized Fe3O4@TiO2 yolk–shell microspheres exhibit significantly enhanced microwave absorption properties compared with pure Fe3O4 and our previously reported Fe3O4@TiO2 core–shell microspheres, which may result from the unique yolk–shell structure with a large surface area and high porosity, as well as synergistic effects between the functional Fe3O4 cores and TiO2 shells. 相似文献
983.
Jun Yuan Ye Zhong Shiliang Li Xue Zhao Guoqin Luan Zhenjiang Zhao Jin Huang Honglin Li Yufang Xu 《中国化学》2013,(9):1192-1198
A series of triazole and benzotriazole derivatives as novel p90 ribosomal S6 protein kinase 2 (RSK2) inhibitors were designed and synthesized. The in vitro activities against RSK2 were evaluated, and among 14 compounds, compounds 5, 6, 11, 12, 13 and 14 exhibited enzyme IC50 values of 8.91, 2.86, 3.19, 3.05, 4.49 and 2.09 μmol/L re- spectively. The proposed binding modes were simulated using molecular docking method, and the docking results coupled with the stmcture-activi1:y relationship (SAR) analysis indicated that all these active compounds bound to the RSK2 ATP binding site at NTKD, and the electron-donating groups on the 4-position of phenyl were the deter- minant point for the inhibitory activity. 相似文献
984.
The C-I bond dissociation enthalpies (BDE) of various organic iodides were calculated using high-level theoretical methods including MP2 and CCSD(T) with extrapolated basis set as well as a number of density functional theory methods. After systematic evaluation of the theoretical results against available experimental C-I BDEs, it was found that the MPW LYPIM method gave the lowest root mean square error. We, therefore, used this method to examine the substituent effects on different categories of C(sp3)-I and C(sp2)-I bonds. Fur thermore, the remote substituent effects on the C-I BDEs of substituted iodobenzenes and substituted (iodomethyl)benzenes were also investigated at the same level. The C-I BDEs of typical heteroaromatic iodides including five-membered and six-membered heterocyclic iodides were also examined. 相似文献
985.
Simple and readily available chiral N‐(sulfinyl)allylamines have been developed as efficient novel ligands for the rhodium‐catalyzed enantioselective 1,2‐addition of arylboronic acids to challenging aliphatic α‐ketoesters. By employing the linear or branched sulfinamide‐olefin ligands, interesting enantioselectivity as well as regioselectivity reversal in the related asymmetric additions were observed. 相似文献
986.
Superparamagnetic iron oxide nanoparticles with narrow size distributions were successfully prepared in large scale by a facile one‐pot synthetic method in the presence of hydrophilic polymers, such as polyethylene glycol diacid (HOOC‐PEG‐COOH) and poly(acrylic acid) (PAA). The as‐prepared products were investigated in detail by powder X‐ray diffraction (XRD), thermogravimetric analyses (TGA), transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), and vibrating sample magnetometer (VSM). The interaction between polymers and iron oxide nanoparticles was investigated using Fourier transform infrared spectrometry (FT‐IR). The results show that polymers can be attached onto the surface of iron oxide nanoparticle by bridging coordination and monodentate fashion, respectively. The interaction affects iron oxide nanoparticle properties significantly, such as XRD diffraction intensity, hydrodynamic diameter, isoelectric point, and saturation magnetization. Furthermore, the results of in vitro experiments indicated that iron oxide‐PEG‐COOH nanoparticle is more cytotoxic than iron oxide‐PAA nanoparticle due to different coordinating modes. 相似文献
987.
Concise and efficient three‐component domino [4+1+1] carbocyclization to highly substituted fluoren‐9‐one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis‐cyanation and aryl amination residing in fluoren‐9‐one framework were achieved in a one‐pot operation. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good to excellent chemical yields. 相似文献
988.
Chen Chen Weng Xinliang Xu Xiao Xia Xiong Xiu Lian Lu Yi Feng Zhou 《Russian Journal of General Chemistry》2013,83(12):2447-2452
We have demonstrated that the fragments of Telaprevir can act as organocatalysts for asymmetric aldol reactions between aromatic aldehydes and acetone under mild conditions. The reaction conditions have been optimized in terms of the catalyst nature, choice of temperature, solvent, additive, and the catalyst loading. Under proper conditions, fairly good yield and enantioselectivity have been achieved. 相似文献
989.
990.