Na2SeO3在Fe电极上还原和吸附机理

采用循环伏安法、恒电势电解法、恒电流阶跃法及交流阻抗法研究Na2SeO3提高锌锰合金电沉积电流效率的作用机理.证明在锌锰合金电沉积的条件下，Na2SeO3 阴极被还原为Se32－并吸附在阴极表面上，从而阻止了氢原子在阴极表面的吸附，因而减少了氢离子的阴极还原.拟定了Na2SeO3的反应和吸附机理，用交流阻抗法进一步证明了所拟机理的正确性.     

Photocatalytic Oxidation of Aniline in the Gas Phase Using Porous TiO2 Thin Films

The gas-phase photocatalytic oxidation of aniline on a new kind of porous nano-TiO₂ composite films is investigated. The composite film was prepared on glass fiber with the water glass as binders and dilute H₂SO₄ solution as solidifying reagent. The surface characters were observed by scanning electron microscope. The photocatalytic degradation of aniline on the composite films was carried out in a TiO₂/UV system. Some important factors affecting the photodegradation, such as the concentration of TiO₂, the initial concentration of aniline, and the existing water vapor, are also studied. The product of photocatalytic oxidation was detected by Fourier transform-Infrared. The partial intermediate products were absorbed on TiO₂ surface, which resulted in catalyst deactivation. But when it was irradiated under UV illumination or solar irradiation for some time, the catalyst could be reused without loss of catalytic activity. Translated from the Journal of Wuhan University (Natural Science Edition), 2005, 51(2) (in Chinese)     

Determination of cadmium in water samples by graphite furnace atomic absorption spectrometry after cloud point extraction

The formation of a complex with 2-(5-brom-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP) and cloud point extraction have been applied to the preconcentration of cadmium followed by its determination by graphite furnace atomic absorption spectrometry (GFAAS) using octylphenoxypolyethoxyethanol (TritonX-114) as surfactant. The chemical variables affecting the separation were optimized. At pH 7.0, preconcentration of only 10 mL of sample in the presence of 0.05% TritonX-114 and 2.5 × 10⁻⁶ M 5-Br-PADAP enabled the detection of 0.04 μg/L cadmium. The enrichment factor was 21 for cadmium. The regression equation was A = 0.0439C(μg/L) + 7.2 × 10⁻³. The correlation coefficient was 0.9995. The precision for 10 replicate determinations at 10 μg/L Cd was 2.7% relative standard deviation (RSD). The proposed method has been applied to the determination of cadmium in water samples. The text was submitted by the authors in English.     

A self-assembly/disassembly two-photo ratiometric fluorogenic probe for bacteria imaging

A fluorogenic probe for bacteria imaging was reported. The binding with anionic bacterial surfaces disassembled the self-assembly probe to turn-on the fluorescence and shift pyrene monomer/excimer ratiometric signals.     

Resonance Rayleigh scattering method for the recognition and determination of double-stranded DNA using amikacin

In weakly acidic buffer medium, the interaction of amikacin with calf thymus DNA, yeast RNA and denatured DNA has been investigated by using resonance Rayleigh scattering (RRS) technique. The result shows that calf thymus DNA is capable of enhancing the RRS intensity of the amikacin, while yeast RNA and denatured DNA have very little enhancement effect. Based on the characteristics, a sensitive assay for detecting double-stranded DNA in the presence of denatured DNA and yeast RNA has been developed. The enhancement of the RRS signal is directly proportional to the concentration of double-stranded DNA in the range 0.02-12.0 μg ml⁻¹ for calf thymus DNA and its detection limit (3σ) is 2.5 ng ml⁻¹. The method shows a wide linear range and high sensitivity, and almost no interference can be observed from RNA, denatured DNA, amino acid and most of the metal ions. The trace amounts of nucleic acid in synthetic samples and practical samples are determined with satisfactory results. Therefore, the proposed method is promising for as an effect means for recognition in vivo and determination in situ of double-stranded DNA.     

1,3-二烯基-1,1,3,3-四甲基二硅氧烷/苯乙烯共聚合的环化率与竞聚率

对１３０℃下１，３ 二烯基 １，１，３，３ 四甲基二硅氧烷（ＤＶＤＳ）／苯乙烯（Ｓｔ）的溶液环化共聚合动力学进行了研究．根据低转化率（＜１０％）的共聚物组成及环状结构比例，通过参数估计方法，求得环化率与竞聚率，分别为ｒ１＝０１０２、ｒ２＝３４８、ｒｃ＝００２１０、Ｋｃ＝３８１ｍｏｌ／Ｌ、Ｋ′ｃ＝０３８９ｍｏｌ／Ｌ，同时得到它们９５％置信概率的联合置信区间及其交互影响的联合置信区间．表明ＤＶＤＳ的反应活性较Ｓｔ低，其非环状结构自由基具有较强的分子内环化反应能力；环的位阻效应使环状结构ＤＶＤＳ自由基的活性低于其非环状结构自由基．     

Synthesis of a new class of conformationally rigid phosphino-oxazolines: highly enantioselective ligands for Ir-catalyzed asymmetric hydrogenation

[reaction: see text] A new class of conformationally rigid phosphino-oxazoline ligands were synthesized from readily available enantiopure phenyl glycinol. Ir complexes with these ligands are air-stable and highly enantioselective catalysts for asymmetric hydrogenation of aryl alkenes and alpha,beta-unsaturated esters in up to 99% ee.     

Synthesis and biological activity of novel 2-(3-trifluoromethylphenoxy)-4-trifluoromethylthiazole-5-carboxamide derivatives

Novel 2-(3-trifluoromethylphenoxy)-4-trifluoromethylthiazole-5-carboxamides were designed and synthesized utilizing ethyl 3-amino-4,4,4-trifluoro-2-butenoate as a starting material via six steps. Subsequently, their biological activities were evaluated in the greenhouse. Results indicated that several compounds have some insecticidal or fungicidal activity at 600 g ai/ha and 300 g ai/ha, respectively.     

Crystal engineering of a versatile building block toward the design of novel inorganic-organic coordination architectures

Six novel inorganic-organic coordination supramolecular networks based on a versatile linking unit 4-pyridylthioacetate (pyta) and inorganic Co(II), Cu(II), Ag(I), Zn(II), Mn(II) and Pb(II) salts have been prepared in water medium and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of CoCl(2).6H(2)O with Hpyta afforded a neutral mononuclear complex [Co(pyta)(2)(H(2)O)(4)](1), which exhibits a two-dimensional (2-D) layered architecture through intermolecular O-HO interactions. Reaction of CuCl(2.2H(2)O with Hpyta yielded a neutral one-dimensional (1-D) coordination polymer [[Cu(pyta)(2)(H(2)O].0.5H(2)O](n)(2) consisting of rectangle molecular square units, which show a three-dimensional (3-D) supramolecular network through S...S and O-H...O weak interactions. However, when AgNO(3), Zn(OAc)(2).2H(2)O or MnCl(2).4H(2)O salts were used in the above self-assembled processes, the neutral 2-D coordination polymers [Ag(pyta)](n)(3), [[Zn(pyta)(2)].4H(2)O](n)(4) or [[Mn(pyta)(2)(H(2)O)]](n)(5) with different topologies were obtained, respectively. While substituting the transition metal ions used in 1-5 with Pb(OAc)(2).3H(2)O, a one-dimensional coordination polymer [Pb(pyta)(2)](n)(6), which shows a novel 2-fold interpenetrating 2-D supramolecular architecture through weak SS interactions, was isolated. It is interesting to note that the building block pyta anion exhibits different configurations and coordination modes in the solid structures of complexes 1-6. These results indicate that the versatile nature of this flexible ligand, together with the coordination preferences of the metal centers, play a critical role in construction of these novel coordination polymers or supramolecules. The spectral and thermal properties of these new materials have also been investigated.