Preparation and optical properties of Eu(III) complexes J-aggregate formed on the surface of silver nanoparticles

Ag colloidal nanoparticles coated with Eu(TTA)₃ · 2H₂O complexes were prepared, and it was found that Eu(TTA)₃ · 2H₂O complexes J-aggregate was formed on the surface of Ag nanoparticles according to a red shift (18.2 nm) in UV–Vis spectra. However, there had similar excitation wavelength, which was attributed to existence of Ag nanoparticles. Highly luminescent properties of Ag colloidal nanoparticles were observed, and it was believed to result from low energy transfer between Eu(III) complexes and Ag and the large electromagnetic field arising from the excitation of surface plasmon polariton of Ag nanoparticles.     

Synthesis, crystal structure and spectroscopic properties of an unsymmetrical compound with carbazole and benzothiadiazole units

An unsymmetrical organic compound with carbazole (Cz) as donor and benzothiadiazole (BTD) as acceptor (D-π-A-π∗-D∗) was designed and synthesized via simple Heck reaction. The unique crystal structure of Cz-BTD-Cz∗ shows a ladder-like packing mode. A two molecule pair stacks parallelly with each other in each packing unit. In each cell, one Cz moiety is connected with BTD by vinylene bond in same plane. However, the other Cz group is connected to BTD by a one-end vinyl bond in almost perpendicular position to the coplanar part of the molecule. The shortest intermolecular plane distance is 3.48 ± 0.1 Å. The photophysical properties of Cz-BTD-Cz∗ in solution and in bulky crystalline powder state were studied. In bulk crystalline powder state, it has a red-shifted emission band peaked at 609 nm relative to that in solution, and the FWHM was reduced to only 58 nm. Electrochemical properties were also investigated.     

萃取动力学光度法测定活化剂铝——铝(Ⅲ)-过氧化氢-铜(Ⅱ)-邻氨基酚/氯仿体系

研究了在pH 5.5的弱酸性介质中, 利用Al(Ⅲ)对Cu(Ⅱ)催化H2O2氧化邻氨基酚显色的指示反应的活化作用.用萃取平衡控制反应时间、水相中邻氨基酚的浓度和反应进行的程度.通过在424 nm下测量有机相的吸光度,建立了萃取催化光度法测定活化剂铝的新方法.方法的线性范围为0.004～0.25 mg/L,检出限为1.6×10 -6 g/L.用于水样和茶叶中铝含量的测定,结果满意.     

Molecularly imprinted solid-phase extraction of (-)-ephedrine from Chinese Ephedra

Method of molecularly imprinted solid phase extraction (MISPE) of (-)-ephedrine from Chinese Ephedra has been developed in the research. The molecularly imprinted polymer (MIP) with good selectivity and affinity for (-)-ephedrine was synthesized with (-)-ephedrine as the template, methacrylic acid as the functional monomer. The washing and elution conditions in MISPE were selected and optimized for efficient analyte extraction and sample clean-up. A clean analytical HPLC base line of ephedra extract was obtained after MISPE, which indicated that the sample pre-treatment was efficient. Good recovery and precision were obtained in the assessment for the MISPE-HPLC procedure, which demonstrated it is a reliable method and can be used for the determination of (-)-ephedrine in herbal ephedra.     

Designed nanostructured pt film for electrocatalytic activities by underpotential deposition combined chemical replacement techniques

Multiple-deposited Pt overlayer modified Pt nanoparticle (MD-Pt overlayer/PtNPs) films were deliberately constructed on glassy carbon electrodes through alternately multiple underpotential deposition (UPD) of Ag followed redox replacement reaction by Pt (II) cations. The linear and regular growth of the films characterized by cyclic voltammetry was observed. Atomic force spectroscopy (AFM) provides the surface morphology of the nanostructured Pt films. Rotating disk electrode (RDE) voltammetry and rotating ring-disk electrode (RRDE) voltammetry demonstrate that the MD-Pt overlayer/PtNPs films can catalyze an almost four-electron reduction of O(2) to H(2)O in air-saturated 0.1 M H(2)SO(4). Thus-prepared Pt films behave as novel nanostructured electrocatalysts for dioxygen reduction and hydrogen evolution reaction (HER) with enhanced electrocatalytic activities, in terms of both reduction peak potential and peak current, when compared to that of the bulk polycrystalline Pt electrode. Additionally, it is noted that after multiple replacement cycles, the electrocatalytic activities improved remarkably, although the increased amount of Pt is very low in comparison to that of pre-modified PtNPs due to the intrinsic feature of the UPD-redox replacement technique. In other words, the electrocatalytic activities could be improved markedly without using very much Pt by the technique of tailoring the catalytic surface. These features may provide an interesting way to produce Pt catalysts with a reliable catalytic performance as well as a reduction in cost.     

水溶性聚合物和两亲聚合物:12.环氧乙烷-环氧丙烷无规共聚醚结构与性能的关系

来用连续加料法,以二元醇-KOH为引发剂合成一组不同组成的环氧乙烷-环氧丙烷无规共聚醚,并用核磁共振、红外光谱、示差扫描量热计和热失重等方法对其本体聚合物,用浊点和表面张力测定的方法对其水溶液,进行系统的表征。     

Recent Advances in Rare‐Earth Polypnictides

The polypnictide complexes of rare earth cations have drawn the attention of the scientific community for their uncommon bonding modes and potential applications. Herein, we present a systematic and comprehensive summary on recent advances in the field of rare earth polypnictides, focusing on their synthesis, structures, and reactivities. The structural stabilizing effects imposed by the electropositive rare earth cations as well as the reducing capability of rare earth precursors in the synthesis of these polypnictide complexes are described in this review. We also disscuss in detail the bonding interactions and coordination modes between rare earth cations and polypnictide clusters as well as the similarities and the peculiarity of some structures.     

Biocomposites of covalently linked glucose oxidase on carbon nanotubes for glucose biosensor

The formation of covalently linked composites of multi–walled carbon nanotubes (MWCNT) and glucose oxidase (GOD) with high-function density for use as a biosensing interface is described. The reaction intermediates and the final product were characterized by using FT–IR spectroscopy, and the MWCNT-coated GOD nanocomposites were examined by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Interestingly, it was found that the GOD–MWCNT composites are highly water soluble. Electrochemical characterization of the GOD–MWCNT composites that were modified on a glassy carbon electrode shows that the covalently linked GOD retains its bioactivity and can specifically catalyze the oxidation of glucose. The oxidation current shows a linear dependence on the glucose concentration in the solution in the range of 0.5–40 mM with a detection limit of 30 μM and a detection sensitivity of 11.3 μA/mMcm². The present method may provide a way to synthesize MWCNT related composites with other biomolecules and for the construction of enzymatic reaction-based biofuel cells and biosensors. Supported by grants from the National Natural Science Foundation of China (NSFC, No. 20125515; 90206037; 20375016) and the Natural Science Foundation of Jiangsu Province (Grant No. BK 2004210)     

TiO(2) porous electrodes with hierarchical branched inner channels for charge transport in viscous electrolytes.

Titanium dioxide (TiO(2)) photoelectrodes with micro/nano hierarchical branched inner channels have been prepared by an electrohydrodynamic (EHD) technique and assembled to form dye-sensitized solar cells (DSSCs). Excellent penetration of ionic-liquid electrolytes and enhanced light harvesting in the longer wavelength region are realized within the composite-structure electrode, thus a better fill factor (ff) of 75.3 % and higher conversion efficiency (eta) of 7.1 % are obtained for viscous ionic-liquid electrolytes compared to pure nanostructured films. Hierarchical branched channels in the photoanodes can efficiently improve the transport properties of redox-active species in viscous electrolytes, which is demonstrated by electrical impedance spectroscopy (EIS). The incident monochromatic photon-to-electron conversion efficiency (IPCE) shows that enhanced light scattering in the composite film is of benefit for light harvesting and thus for solar energy conversion efficiency.