Core-satellites assembly of silver nanoparticles on a single gold nanoparticle via metal ion-mediated complex

We report core-satellites (Au-Ag) coupled plasmonic nanoassemblies based on bottom-up, high-density assembly of molecular-scale silver nanoparticles on a single gold nanoparticle surface, and demonstrate direct observation and quantification of enhanced plasmon coupling (i.e., intensity amplification and apparent spectra shift) in a single particle level. We also explore metal ion sensing capability based on our coupled plasmonic core-satellites, which enabled at least 1000 times better detection limit as compared to that of a single plasmonic nanoparticle. Our results demonstrate and suggest substantial promise for the development of coupled plasmonic nanostructures for ultrasensitive detection of various biological and chemical analytes.     

J-aggregation induced low bandgap anthracene-based conjugated molecule for solution-processed solar cells

A new anthracene-based X-shaped conjugated molecule, HBTATHT, was synthesized. Thin film transistors based on unannealed HBTATHT showed a carrier mobility of 0.15 cm(2) V(-1) s(-1) (I(on/off) = 7.9 × 10(6)). Further, a solution processed solar cell made of HBTATHT exhibited promising power conversion efficiencies of 4.84% and 4.70% with PC(61)BM (1?:?0.8 wt ratio) and PC(71)BM (1?:?0.6 wt ratio), respectively.     

Quantitative determination of aceclofenac and its three major metabolites in rat plasma by HPLC-MS/MS

We developed a method for the simultaneous quantification of aceclofenac and its three major metabolites in rat plasma. After protein precipitation with acetonitrile including flufenamic acid as an internal standard (IS), aceclofenac, diclofenac, 4'-hydroxyaceclofenac, 4'-hydroxydiclofenac, and the IS were chromatographed on a reverse-phase C18 analytical column. The isocratic mobile phase of acetonitrile/0.1% formic acid (aq; 9:1 [v/v]) was eluted at 0.3 mL/min. Quantification was performed on a triple-quadrupole mass spectrometer using electrospray ionization, and the ion transitions were monitored in selective reaction-monitoring mode. The coefficient of variation in the assay precision was less than 8%, and the accuracy was 92-103%. This method was successfully used to measure the concentrations of aceclofenac and its three major metabolites in rat plasma following the oral administration of a single 20 mg/kg oral dose of aceclofenac.     

Gold-catalyzed hydrosilyloxylation driving tandem aldol and mannich reactions

The chemoselective formation of an enolate from alkyne in the presence of a carbonyl and imine group was realized, which constructed a variety of structural motifs under exceedingly mild reaction conditions in a tandem process. Reaction driving tandem hydrosilyloxylation/aldol reactions was achieved through the formation of enol silyl ethers catalytically generated in situ from readily available alkynes. These reactions were expanded to obtain β-amino enol silyl ethers in good yields via the tandem hydrosilyloxylation/isomerization/Mannich reaction.     

Self-organization of bent rod molecules into hexagonally ordered vesicular columns

Bent-shaped rigid-core molecules with flexible chiral dendrons grafted to the outer side of the bend were synthesized and characterized by circular dichroism, differential scanning calorimetry, X-ray scatterings, and transmission electron microscopy in solution and the solid state. The bent aromatic rods based on hepta- and nonaphenylene with nitrile groups at both ends self-assemble into well-ordered hollow tubular structures in aqueous solution, while the bent rod based on heptaphenylene without nitrile groups showed no apparent aggregations in aqueous solution. In the solid state, the rigid-flexible molecules based on heptaphenylene rod without the nitrile group self-assemble into a 2D oblique columnar structure with the columnar cross-section containing two interlocked molecules. Remarkably, the rigid flexible molecules based on hepta-, nona-, and undecaphenylene with nitrile groups self-assemble into a hexagonal columnar structure with weak 3D order. A model of vesicular channel structure is proposed based on small- and wide-angle X-ray diffraction on oriented fibers, density measurement, reconstruction and simulation of electron density maps, and molecular dynamics simulation. In contrast to the hollow tubular structure found in solution, in the solid both the outside and the interior of the columns are filled by the pendant aliphatic coils. Filling of the interior of these vesicular channels is made possible by some bent rod molecules turning their obtuse apex inward. One in 7, 2 in 8, and 4 in 10 molecules are thus inverted in a column slice in compounds with hepta-, nona-, and undecaphenylene cores, respectively. These are new examples of vesicular double-segregated columnar structures recently discovered in some dendrons.     

A highly efficient transacetalization of 2-formylpyrrole acetals in alkaline media

The reaction of 2-formylpyrrole acetals with sodium alkoxide in alcohols at reflux temperature smoothly proceeded to generate corresponding transacetalization products in nearly quantitative yields.A plausible mechanism involving the formation of a highly reactive intermediate azafulvene species was proposed to explain the observed transformation.     

Oxalic acid-assisted preparation of LiFePO4/C cathode material for lithium-ion batteries

LiFePO₄/C composite is synthesized by oxalic acid-assisted rheological phase method. Fe₂O₃ and LiH₂PO₄ are chosen as the starting materials, sucrose as carbon sources, and oxalic acid as the additive. The crystalline structure and morphology of the products are characterized by X-ray diffraction and field emission scanning electron microscopy. The charge–discharge kinetics of LiFePO₄ electrode is investigated using cyclic voltammetry and electrochemical impedance spectroscopy. It is found that the introduction of appropriate amount of oxalic acid leads to smaller particle sizes, more homogeneous size distribution, and some Fe₂P produced in the final products, resulting in reduced polarization, impedance, and improved Li⁺ ion diffusion coefficient. The best cell performance is delivered by the sample with R = 1.5 (R of the molar ratio of oxalic acid to LiH₂PO₄). Its discharge capacity is 154 mAh g⁻¹ at 0.2 C rate and 120 mAh g⁻¹ at 5.0 C rate. At the same time, it exhibits an excellent cycling stability; no obvious decrease even after 1,000 cycles at 1.0 C rate.     

诱惑红溶液标准物质的研制及不确定度评定

建立了食用合成色素诱惑红溶液标准物质的制备和定值方法,研制了100 mg/L的诱惑红溶液标准物质。采用制备液相色谱对筛选的市售原料纯化,得到纯度大于99%的诱惑红纯品;通过核磁共振(1H NMR谱)和液相色谱-质谱(HPLC-LTQ/MS)准确定性分析后,利用高效液相色谱法(HPLC)对诱惑红纯物质进行纯度定值。以0.1 mol/L乙酸铵和甲醇为流动相进行等度洗脱,采用Intersil ODS-C18(250 mm×4.6 mm,5μm)进行分离,检测波长240 nm。为保证纯度测量的准确性,采用多家联合定值对诱惑红的纯度进行定值,诱惑红纯物质的定值纯度为99.61%(λ=240 nm)。诱惑红溶液标准物质经重量-容量法配制后,进行均匀性和稳定性实验,浓度赋值后进行不确定度评定,诱惑红溶液的量值为100 mg/L,扩展相对不确定度为1.0%(k=2)。该溶液标准物质已批准为国家级标准物质,可为相关部门提供检测标准。     

盐酸小檗碱含量测定的荧光新方法研究

研究了盐酸小檗碱(BER)在八元瓜环水溶液中的荧光光谱行为。八元瓜环与BER发生超分子相互作用后,使溶液中BER的荧光强度增加,且BER的浓度在1.90×10-8～1.00×10-5mol.L-1范围内与荧光强度呈良好的线性关系(r=0.996 1),据此建立了一种测定BER含量的荧光新方法。该方法的检出限为1.90×10-8mol.L-1,且不需对样品进行分离提纯,可直接在水溶液中简单准确地测定BER的含量,避免了有机溶剂和萃取剂的使用,具有灵敏度高、选择性好、线性范围宽等特点。该法对片剂、血清和尿样中BER含量的测定结果与药典方法较一致。     

Chlorination reaction behavior of Zircaloy-4 hulls: experimental and theoretical approaches

Chlorination reaction behavior of Zircaloy-4 (Zry-4) cladding hulls was demonstrated by using a quartz reactor system. By reacting at 380 °C for 3 h, mass of the Zry-4 hulls decreased by 65.8 wt% with Cl₂ utilization of 87.1 mol%. Composition of collected product was analyzed and it was revealed that concentration of Zr was higher than 99.97 wt%. The purity of Zr in the experimental result was higher than expectation when considering Sn (1.31 wt%) and Fe (0.25 wt%) contents which can produce gaseous SnCl₄ and FeCl₃ at the experimental condition. Theoretical calculations were performed to clarify the high purity of Zr by using the HSC code. The simulation results revealed that formation of ZrCl₄ is more preferred than SnCl₄, FeCl₃, and CrCl₃. The preference of chloride formation was confirmed by the theoretical calculation, and it was suggested that the major constituents of Zry-4 might react with Cl₂ to produce chlorides in an order of ZrCl₄ > CrCl₃ > SnCl₄ > FeCl₃. It was also suggested that continuous removal of ZrCl₄ and sufficient supply of Zr source during the chlorination reaction might have contributed to the high purity of Zr.