Enantioselective iodolactonization catalyzed by chiral quaternary ammonium salts derived from cinchonidine

Chiral quaternary ammonium salts derived from cinchonidine have been applied to catalyze the stereoselective iodolactonizations of trans-5-aryl-4-pentenoic acids leading to a mixture of two regioselectively iodolactonized products with fair to excellent yield (37-98%) and moderate enantioselectivity (exo = 42.0% ee, endo = 31.0% ee) under mild conditions. This work is the first example of asymmetric iodolactonization reaction in the presence of less than a stoichiometric amount of chiral reagent.     

An optical surface plasmon resonance biosensor for determination of tetanus toxin

Surface plasmon resonance (SPR) has been successfully applied for the simple, rapid, and label-free assay of various biomolecules. This assay evaluates a novel wavelength modulation SPR biosensor for the detection of tetanus toxin. The wavelength modulation SPR biosensor is designed based on fixing the incident angle of light and measuring the reflected intensities in the resonance wavelength range spanning 400-800 nm simultaneously. Tetanus toxin (TeNT), one of the most potent toxins known, is synthesized as a 150 kDa single polypeptide chain. The SPR biosensor has been shown to be capable of directly detecting concentration of tetanus toxin as low as 0.028 Lf ml⁻¹. Under selected experimental conditions, the SPR biosensor has a good reproducibility, sensitivity and reversibility. The results illustrate how wavelength modulation SPR biosensor can be used to detect biomolecular interactions.     

A Novel Dimeric Eremophilane from Ligularia virgaurea spp. oligocephala

A novel dimeric eremophilane, ligulolide B, was isolated from the alcoholic extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structure was elucidated by various spectroscopic methods including intensive 2D NMR techniques （^1H-^1H COSY, gHMQC, gHMBC and ^1H-^1H NOESY） and HR-ESI-MS.     

膜渗透与离子色谱联用技术测定蔬菜中亚硝酸盐和硝酸盐

建立了膜渗析与离子色谱联用技术分析蔬菜等复杂基体中亚硝酸盐和硝酸盐的方法。蔬菜样品经沸水浴后,试样液通过膜渗析除去水溶性大分子杂质和颗粒,直接进入离子色谱分析。渗析池采用0.20μm的醋酸纤维为渗析膜,以水为接收液,分析柱为Metrosep A Supp4-250阴离子交换柱,以1.8mmol/L Na2CO3 1.7mmol/L NaHCO3为流动相,采用化学抑制电导检测。以20g称样计量,方法中NO2-、NO3-的检出限分别为0.075mg/kg和0.105mg/kg;实际样品的加标回收率分别为80.6%~98.7%和90.5%~114%;相对标准偏差(RSD)≤10%。本方法前处理简单,重现性好,准确度高。     

Zn:Er:LiNbO3单晶的坩埚下降法生长及光谱特性

报道了ZnErLiNbO3单晶的坩埚下降法生长工艺. 通过控制晶体生长固液界面的温度梯度(30～35 ℃·cm-1)、晶体的生长速度(0.8～1.5 mm·h-1)、密闭Pt坩埚等条件生长了宏观无缺陷的Zn2+(3%)和Er3+(0.6%)共掺的LiNbO3单晶. 用X射线衍射(XRD)和差热分析(DTA)表征了获得的晶体, 并测量了晶体不同部位的吸收光谱和荧光谱. 从吸收光谱以及由XRD数据计算所得的晶胞参数推断, 沿生长方向Er3+在晶体中的浓度分布逐步减少. 光谱数据表明, 晶体底部样品的吸收强度和荧光强度要比顶部大, 而对应于Er3+上能级4S3/2和2H11/2跃迁至基态4I15/2的绿光发射, 晶体底部却比顶部表现出更高的上转换效率. 从晶体的内部结构、缺陷情况以及Er3+的分凝现象解释了产生上述现象的内在机制.     

A novel route for waste water treatment: photo-assisted Fenton degradation of dye pollutants accumulated in natural polyelectrolyte microshells

The efficient accumulation of dyes in constructed natural polyelectrolyte microshells under moderate conditions, combined with the photo-assisted Fenton reagent, opens a new route for the effective elimination of dye pollutants from waste water.     

单氨基取代3∶1不对称酞菁锌的合成及其在有机溶剂中聚集状态的研究

Monoamino substituted asymmetrical phthalocyanine zinc(Ⅱ), 2-amino-9,10,16,17,23,24-hexapentyloxy phthalocyanine zinc(Ⅱ), was synthesized by statistical condensation and characterized by elemental analysis, UV-Vis, IR and TOF-MS. The aggregative behavior was studied in DMF, THF and CH₂Cl₂. The results show that it is not aggregateve in DMF and THF, whereas form dimer in CH₂Cl₂ at 8 × 10^-7～8 × 10^-6 mol·L^-1. The equilibrium constant for the dimer was calculated at the same time, indicating that the less polar solvent is unfavorable for the presence of the monomer.     

盐卤硼酸盐化学──ⅩⅩⅧ.氯柱硼镁石的激光拉曼光谱

本文研究了氯柱硼镁石硼酸和硼砂的晶体和它们在水溶液中的激光拉曼光谱，并与某些阴酸盐的谱图进行对比．初步提出硼氧配阴离子的聚合形式，为进行氯柱硼镁石结构分析提供实验依据．     

C NMR spectra of cyclomercurated ferrocenylimines: Substituent effects and conformations in the ferrocenes

Three series of cyclomercurated ferrocenylimines (2-chloromercurio-ferrocenylimines) have been studied using ¹³C NMR spectroscopy. Good to excellent linear relationships have been found to exist between the chemical shifts of the carbon atoms in the ferrocenyl moiety and normal Hammett substituent constants σ_m and σ_p. The δ values of the iminyl carbon atoms show excellent linear correlations with the σ values. In three series of the ferrocenes, the sensitivity of the carbon atoms to the substituent effect is different, which is discussed in terms of the twist angle between the N-phenyl ring and the C---C=N---C plane. The relative sensitivity of the chemical shifts on different positions in ferrocenyl moiety to the substituent effect has also been presented.     

奎宁修饰的纳米铑簇合物催化丙酮酸乙酯对映选择性加氢反应研究

研究了奎宁作手性修饰剂修饰的负载型纳米铑簇合物催化剂 (Rh/ PVP-γ-Al2 O3)催化丙酮酸乙酯不对称氢化反应 ,在该反应中手性修饰剂奎宁不仅具有手性诱导作用 ,而且还有明显加速反应的作用 ;载体γ-Al2 O3在促进提高催化剂活性和对映选择性方面也有很重要的影响 .在优化的反应条件 [2 0℃ ,7.0 MPaH2 ,c(奎宁 ) =3 .86× 1 0 - 3mol/ L,四氢呋喃作溶剂 ]下 ,丙酮酸乙酯不对称加氢的转化频率 (TOF)为871 h- 1 ,对映选择性达到了 5 4.7% ;反应温度降低到 3℃时 ,对映选择性达到 5 9.2 % .