Synthesis and characterization of monodispersed core-shell spherical colloids with movable cores

Gold nanoparticles have been conformally coated with amorphous silica (using a sol-gel method) and then an organic polymer (via surface-grafted, atom transfer radical polymerization) to form spherical colloids with a core-double-shell structure. The thickness of silica and polymer shells could be conveniently controlled in the range of tens to several hundred nanometers by changing the concentration of the reagent and/or the reaction time. Selective removal of the silica layer (through etching in aqueous HF) led to the formation of hollow polymer beads containing movable gold cores. This new form of core-shell particles provides a unique system for measuring the feature size and transport property associated with hollow particles. In one demonstration, we showed that the thickness of a closed polymer shell could be obtained by mapping the electrons backscattered from the core and shell. In another demonstration, the plasmon resonance band of the gold cores was used as an optical probe to follow the diffusion kinetics of chemical reagents across the polymer shells.     

A novel method of the separation/preconcentration and determination of trace molybdenum(VI) in water samples using microcrystalline triphenylmethane loaded with salicyl fluorone

It is the first time that triphenylmethane was used as an adsorbent to preconcentrate and separate trace amount of molybdenum in water samples. The effects of different parameters, such as acidity, stirring time and various metal ions, the amounts of triphenylmethane and salicyl fluorine, etc. on the enrichment yield of molybdenum have been studied to optimize the experimental conditions. Under the optimum conditions, molybdenum can be adsorbed on the surface of microcrystalline triphenylmethane loaded with salicyl fluorone by the intermolecular action strength. The possible reaction mechanism for the enrichment of molybdenum was discussed in detail in this paper. Mo(VI) can be completely separated from Pb(II), Co(II), Cu(II), Cr(III), Ni(II), Hg(II), Zn(II), Cd(II), Fe(III) and Al(III) in the solution. The proposed method was successfully applied to the determination of trace amount of molybdenum in various water samples by spectrophotometry after preconcentration using microcrystalline triphenylmethane. The preconcentration factor is from 83 (500 ml water sample was enriched to 6.0 ml) to 166 (1000 ml water sample was enriched to 6.0 ml). The detection limit is 1.3 × 10⁻⁵ mg l⁻¹ and the linearity is maintained in the concentration range 3.8 × 10⁻³ to 0.36 mg l⁻¹ with a correlation coefficient of 0.9998. The recoveries are in the range of 93.5-104%. The relative standard deviation is 1.8-2.9%. Analytical results obtained with this novel method are very satisfactory.     

电化学检测在流动注射分析中的应用

评述了近几年来电化学检测在流动注射分析中的应用，展望了流动注射电化学分析法的发展动向。     

西印度蔗螟聚集信息素次要组份合成方法的改进

2-甲基-4-庚醇和2-甲基-4-辛醇是西印度蔗螟(Metamasiushemipterus)聚集信息素的次要组份，本文以天然产物(S)-亮氨酸为原料合成出了2-甲基-4-庚醇及2-甲基-4-辛醇的所有对映异构体，其关键步骤是由(2S)-4-甲基-1,2-戊二醇合成出(2S)和(2R)-4-甲基-1,2-环氧戊烷两种重要中间体，目标产物光学纯度可达95%以上。     

邻苯二胺合钴氧合反应的研究Ⅰ 水溶液中配合物及其氧合配合物稳定常数的测定

自１９３８年Tsumaki报道犤１犦氧载体以来，这方面的研究已有很大进展犤２犦，只是理论研究居多。氧载体的氧合常数是氧载体研究中的一个重要参数，它的测定是氧载体研究中的一项重要内容，用pH电位法测定氧载体的氧合常数已有研究报道犤２～４犦，作者在研究中发现，邻苯二胺合钴（o－Phdn－Co）配合物在固相和水溶液中与O２反应时表现出很大差异，其反应产物的组成比分别为液相配合物Co∶O２＝２∶１，而固相配合物Co∶O２＝１∶２，为究其成因和进行理论探讨，有必要先测定其氧合常数。由于o－Phdn－Co配合物的配位常数也未见文献…     

脱氢姜黄烯及其类似物的合成

利用苯乙酮及苯乙酮衍生物,经过傅-克乙酰化反应、偶联反应、Wittig烯化反应,合成了脱氢姜黄烯及其类似物.再经选择性催化氢化反应,可分别得到α-姜黄烯、黄根醇甲醚及姜黄氢醌甲醚.     

Self-assembly, optical behavior, and permeability of a novel capsule based on an azo dye and polyelectrolytes

A novel capsule composed of an azo dye, Congo red (CR), and different polymers, including poly(styrenesulfonate, sodium salt) (PSS), poly(allylamine hydrochloride) (PAH), and poly(diallyldimethylammonium chloride) (PDDA), have been successfully fabricated by the layer-by-layer self-assembly technique. The stepwise linear deposition process was monitored by means of UV-visible absorption measurements. The formation of hollow capsules was verified by confocal laser scanning microscopy (CLSM) and scanning force microscopy (SFM). The resulting hollow PSS/PAH/CR/PDDA capsules displayed a sensitive response to visible light. Optical changes of the hollow capsules prior to and after the photoreaction were investigated in detail by means of UV-visible spectroscopy, CLSM, and SFM. It was found that the photochemical reaction of the assembled hollow capsules depends strongly on the matrix. Qualitative results on the permeability of the hollow capsule walls with CR as one component indicate that the permeability of the walls can be easily photo-controlled at varying irradiation time intervals without addition of external chemicals.     

Interactions of hemoglobin with lecithin liposomes

In this paper, the interaction of hemoglobin (Hb) with lecithin liposomes is studied by UV-vis spectroscopy, fluorescent spectroscopy, and transmission electron microscopy. The adsorption of Hb on liposomes is likely to be related to the hydrophobic interaction between Hb and liposomes, which brings about the increase of the microenvironmental polarity (I ₁/I ₃) and the decrease of the fluorescence polarization (P) of lecithin liposomes. These results are considered to be that the adsorption of Hb on liposomes makes the spaces between the lecithin molecules increase, and a temporary gap is consequently formed in the liposomal bilayer membranes. The leakage of aqueous-space marker from the liposomes is increased with the addition of Hb.     

Bioinspired manganese complexes catalyzed epoxidation for the synthesis of the epoxyketone fragment of carfilzomib

We report herein an efficient catalytic epoxidation reaction for the synthesis of epoxyketone (tert-butyl ((S)-4-methyl-1-((R)-2-methyloxiran-2-yl)-1-oxopentan-2-yl)carbamate), which is an important synthetic intermediate of carfilzomib.     

Study on the interaction between nucleic acids and cationic surfactants

The interactions of nucleic acids and cationic surfactants (cetylpyridine bromide (CPB) and cetyltrimethylammonium bromide (CTMAB)) in aqueous solution have been studied using the techniques of resonance light scattering (RLS) spectroscopy, the absorption spectroscopy, zeta potential assay and NMR assignment measurement. It is considered that CPB or CTMAB can assemble on the surface of nucleic acid via electrostatic and hydrophobic forces, which results in the formation of large associate of nucleic acid-cationic surfactant and RLS enhancement of nucleic acid. Besides these forces, the pi-pi stacking force between CPB and nucleic acid also exists in the associate. In comparison with CTMAB, CPB has larger enhancement on RLS of nucleic acid, which is attributed to that the enhancement of the former is only due to the absorption of the bases of nucleic acid, while the enhancement of the latter is own to the synergetic resonance caused by the absorption of both bases of nucleic acid and the pyridyl in CPB. These results have important implication for understanding the influence of surfactants on nucleic acid functionality in life science.