Hybrid Organic–Inorganic Rotaxanes,Including a Hetero‐Hybrid [3]Rotaxane Featuring Two Distinct Heterometallic Rings and a Molecular Shuttle

[2] and [3] hybrid rotaxanes are reported based on {Ti₇M} rings (M is a trivalent metal such as Fe^III or Ga^III). NMR studies show that [2]rotaxanes can act as molecular shuttles, while EPR studies of [3]rotaxanes show weak interactions between the paramagnetic components of the supramolecular assemblies.     

Stabilizing Lithium Plating by a Biphasic Surface Layer Formed In Situ

The dendritic growth of Li metal leads to electrode degradation and safety concerns, impeding its application in building high energy density batteries. Forming a protective layer on the Li surface that is electron‐insulating, ion‐conducting, and maintains an intimate interface is critical. We herein demonstrate that Li plating is stabilized by a biphasic surface layer composed of a lithium‐indium alloy and a lithium halide, formed in situ by the reaction of an electrolyte additive with Li metal. This stabilization is attributed to the fast lithium migration though the alloy bulk and lithium halide surface, which is enabled by the electric field across the layer that is established owing to the electron‐insulating halide phase. A greatly stabilized Li‐electrolyte interface and dendrite‐free plating over 400 hours in Li|Li symmetric cells using an alkyl carbonate electrolyte is demonstrated. High energy efficiency operation of the Li₄Ti₅O₁₂ (LTO)|Li cell over 1000 cycles is achieved.     

Synthesis and characterization of functionalized 1,3-bis(2- alkyltetrazol-5-yl)triazenes

A series of 1,3-bis(2-alkyltetrazol-5-yl)triazenes have been synthesized in high yields by treatment of sodium nitrite and hydrochloric acid with substituted-5-aminotetrazoles. All compounds were fully characterized using IR spectroscopy,~1H NMR and~(13) C NMR spectroscopy and high resolution mass spectrometer(HRMS). Most of these triazenes exhibit good detonation performance comparable with TNT and low melting points ranging from 81°C to 106°C, which are suitable for melt-cast explosives.Among these compounds, 1,3-bis(2-azidoethyltetrazol-5-yl)triazene(2g) displays a low melting point(106°C), moderate onset decomposition temperature(183°C) and good detonation performance(D:7087 m/s; P: 17.6 GPa).     

Supramolecular Detoxification of Colchicine through Electrochemical Recognition

The complex characteristics of p-sulfonated calix[n]arene and colchicine were examined using various techniques. Cyclic voltammetry indicated that the structural matching and electrostatic interactions were the dominant stabilizing factors for the host–guest complexes. The method showed a long linear voltammetric range for p-sulfonated calix[4]arene from 1?×?10^?8 to 1?×?10^?6?mol?L^?1 with a detection limit of 3?×?10^?9?mol?L^?1. Ultraviolet absorption spectroscopy confirmed that a 1:1 ratio complex was formed. Molecular mechanics showed that the benzene ring of colchicine entered the p-sulfonated calix[4]arene cavity. The solubility of colchicine increased with the p-sulfonated calix[4]arene concentration 50-fold from 0.13 to 6.4?mol?L^?1. The simulation of cell membrane permeability indicated that colchicine was released from the colchicine-p-sulfonated calix[4]arene complex and entered the hydrophobic micelles. These results show that p-sulfonated calix[4]arene is suitable as a drug carrier for colchicine. This work has expanded applications of drug loading, transport, and targeted release for the treatment of gout.     

Synthesis and antiproliferative activity of novel A-homo-B-norsteroid thiadiazole derivatives

Using cholesterol as a starting material, two novel steroidal thiadiazole derivatives possessing a structure of A-homo lactam and a B-nor steroidal skeleton were designed and synthesized by six steps of reactions, and their antiproliferative activities were assayed against various cancer cell lines. The result shows that compound 7b displays an excellent selective inhibition to A-549 (human lung carcinoma) cancer cell lines with an IC₅₀ value of 8.0 μM.     

Electrochemical co-deposition of reduced graphene oxide-gold nanocomposite on an ITO substrate and its application in the detection of dopamine

The simultaneous deposition of rGO and gold nano structures has been achieved by electrodeposition from mixed solutions containing graphene oxide(GO)and a gold precursor.Scanning electron microscope(SEM),Raman spectroscopy and atomic force microscopy(AFM)have been employed to reveal the morphology,uniformity and practical stability of the nanocomposite films on the indium tin oxide(ITO)substrate.The AFM data showed heights of tens of nanometers of the nanocomposite,suggesting that multilayers of rGO with gold nanoparticles had been formed as a result of the electrochemical co-deposition.Differential pulse voltammetry(DPV),as a widely used analytical technique,has been carried out on the rGO-Au/ITO electrode for the quantitative detection of dopamine(DA).The detection limit(S/N=3)for the determination of DA was evaluated as 0.6μM.     

Oxidation of ethanol on carbon-supported oxide-rich Pd–W bimetallic nanoparticles in alkaline media

Carbon-supported oxide-rich Pd–W bimetallic nanoparticles were prepared by chemical reduction methods. The existence of oxides in the electrocatalysts is confirmed by X-ray photoelectron spectrum (XPS) and high resolution transmission electron microscopy. XPS analysis indicates that the oxygen atoms account for about 50% of all the atoms in Pd–W bimetallic nanoparticles. Compared to Pd/C catalyst, the carbon-supported oxide-rich Pd–W bimetallic nanoparticles exhibit a better catalytic activity for the anode oxidation of ethanol in alkaline media. The onset potential of the as prepared oxide-rich Pd_0.8W_0.2/C catalyst (Pd: W = 8: 2, metal atom ratio) for ethanol oxidation is negative shifted about 90 mV comparing to Pd/C catalyst. The oxide-rich Pd–W/C electrocatalysts provide a new model of noble-metal/promoter system as an extreme case of making the promoter (WO₃) closely adjacent to the noble metal (Pd) by fabricating nanoparticles containing both atom-clusters of oxides and the noble metal atoms.

     

基于界面热阻等效模型的超导磁体热输运分析

为解决直接冷却超导磁体中接触界面热阻造成的传热不连续问题,以实验数据为依据采用等效模型模拟接触界面热阻;基于有限元理论分析界面热阻对超导磁体热输运的影响;仿真结果表明等效模型的采用有助于解决低温下超导磁体接触界面间传热的不连续性问题,为研究高温超导磁体的热输运机理提供了一种新思路.