羧酸铜催化反应的研究——Ⅰ.羧酸铜催化醛肟转变为睛

本文报道了在多种羧酸铜催化下,醛肟在含有氰基的溶剂中(如CH_3CN、CH_3OCH_2CH_2CN等),均可脱水转变成相应的腈。反应条件温和,产率较高。具有不同空间和电性效应取代基的羧酸铜对反应的产率影响不大。实验中还发现溶剂乙腈参与了上述反应。     

Experimental and theoretical study on the olefin metathesis of alkenyl Baylis-Hillman adducts using second-generation Grubbs catalyst

[reaction: see text] We have investigated the olefin metathesis from alkenyl Baylis-Hillman adducts using second-generation Grubbs catalyst. In the experiment, the ring-closing metathesis (RCM) product could not be found, while the cross-metathesis (CM) products were found. The computational studies provided consistent explanations for the experimental result. The most limiting factor for the RCM process using second-generation Grubbs catalyst is caused by the high strain and steric effect in the metallacyclobutane intermediates.     

催化动力学分光光度法测定痕量锰(Ⅱ)

研究了氢氧化钠介质中 ,痕量锰催化过氧化氢氧化桑色素褪色反应及其动力学条件 ,建立了催化动力学测定痕量锰的新方法。Mn (Ⅱ )的测定线性范围为 0 0 0 5～ 0 0 60 μg/2 5mL ,检出限为 7 8× 1 0 - 10 g·mL- 1。用于大米中痕量Mn (Ⅱ )的测定 ,结果满意。     

Simultaneous determination of inorganic nitrogen species by microcolumn ion chromatography

Inorganic nitrogen species (nitrate, nitrite and ammonium ions) were simultaneously determined by microcolumn ion chromatography. Nitrate and nitrite were determined by UV detection at 206 nm, whereas ammonium ion was determined by fluorescence detection at excitation 410 nm and emission 470 nm. The latter fluorescence detection is based on the postcolumn reaction of ammonium ion with o-phthalaldehyde in the presence of 2-mercaptoethanol. Effects of the reagent concentration, pH, and other reaction conditions on the signal intensity were examined, and the optimum condition was explored. The present method allowed simultaneous determination of nitrate, nitrite and ammonium ions in river water.     

Fe-Co-Ni合金纳米线有序阵列的模板合成与磁性

以二次阳极氧化的氧化铝膜为模板，用电化学沉积的方法成功地合成了Fe-Co-Ni三组份有序纳米线阵列.扫描电子显微镜（SEM）和透射电子显微镜(TEM)观察表明纳米线表面光滑、有序、高长径比；磁性测量表明,其矫顽力较同组份的膜材料有较大的提高.将样品在惰性气体氛围中不同温度下退火，随着退火温度增加，其纵向矫顽力有一个极值，而对应的横向矫顽力没有类似的变化，关于这一现象的机理,本文进行了初步的讨论. 图5参15     

Photocurrent generation in multilayer self-assembly films fabricated from water-soluble poly(phenylene vinylene)

A novel, water-soluble, cationic PPV derivative poly[(2,5-bis(3-bromotrimethylammoniopropoxy)-phenylene-1,4-divinylene)-alt-1,4-(2,5-bis(2-(2-hydroxyethoxy)ethoxy))phenylene vinylene] (BH-PPV) has been synthesized by a Heck coupling reaction. Multilayered assemblies of the BH-PPV and the sodium salt of hexa(sulfobutyl)fullerenes (C(60)-HS) were fabricated successfully by an alternate deposition technique. The multilayer structures were studied by UV/Vis spectroscopy, small angle X-ray diffraction, and atomic force microscopy. The photoinduced charge transfer property of the self-assembled multilayer film was also measured by a three-electrode cell technique. A steady and rapid cathodic 5.5 microA cm(-2) photocurrent response was measured as the irradiation of the multilayer film was switched on and off. Importantly, the response of on/off cycling is prompt and reproducible. A possible mechanism for the electron-transfer process is proposed.     

Toward the molecular flashlight: preparation,properties, and photophysics of a hypericin-luciferin tethered molecule

The synthesis of a molecule containing hypericin and luciferin moieties joined by a tether is reported. The light-induced (in vitro) antiviral activity as well as the photophysical properties of this new compound are measured and compared with those of the parent compounds, hypericin and pseudohypericin. This tethered molecule exhibits excited-state behavior that is very similar to that of its parent compounds and antiviral activity that is identical, within experimental error, to that of its more closely related parent compound, pseudohypericin. The implications for a photodynamic therapy that is independent of external light sources are discussed.     

含胆汁酸和胆固醇的双亲性聚合物的研究进展

胆固醇和胆汁酸是广泛存在于自然界中的天然物质 ,生物相容性好 ,被广泛地用于高分子的疏水性改性 ,得到的双亲性聚合物 ,在水相中可以自组装或自聚集成纳米粒子。本文综述了含胆固醇或胆汁酸的双亲性聚合物的最新研究进展以及它们在药物载体系统中的应用。     

Reversed-phase liquid chromatographic method for the analysis of aminoglycoside antibiotics using pre-column derivatization with phenylisocyanate

A pre-column derivatization liquid chromatographic method has been developed for the analysis of aminoglycoside antibiotics using phenylisocyanate as a derivatization reagent. Derivatives including kanamycin, neomycin and gentamicin were formed by reaction of the analytes with phenylisocyanate in the presence of triethylamine. Phenylisocyanato groups were attached to corresponding amino groups of aminoglycoside and their molecular mass was confirmed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). The experimental conditions for derivatization and separation of aminoglycoside derivatives were optimized and validated. A simple liquid chromatographic method for the determination of aminoglycoside antibiotics was demonstrated.     

Methotrexate-loaded biodegradable polymeric micelles: preparation, physicochemical properties and in vitro drug release

Polymeric micelles based on amphiphilic diblock copolymers methoxy poly(ethylene glycol)-polylactide with various hydrophobic lengths were designed as carriers of poorly water-soluble anticancer drug methotrexate (MTX). Relationship between physicochemical characteristics of micelles and release behavior was explored. The critical micelle concentration was determined by fluorescence spectroscopy using 9-chloromethyl anthracene as fluorescence probe. Core-shell type polymeric micelles were prepared by free-surfactant dialysis technique. The mean size of micelles loaded with MTX was 50-200 nm with narrow polydispersity. Physicochemical properties of drug-loaded micelles were evaluated. In vitro release behavior of MTX was also investigated. MTX was continuously released from micelles and less than 50% MTX was released in 5 days. Release rate was dependent on chemical structures of micelles and enhanced by decreasing polylactide lengths.