Studies on the optical analogues of zoapatanol: Synthesis of key intermediate (2S,3R)-2-citronellyl-6-methylene-heptan-2,3,7-triol

The key intermediate (2S, 3R)-2-citronellyl-6-methylene-heptan-2,3,7-triol (8) of analogues of zoapatanol was synthesized in seven steps from the chiral synthon 2. The absolute configuration of the new chiral centre in compounds 5a-8 was identified as S by Mukaiyama's method.     

Synthesis and decoloration capacity of well-defined and PMMA-grafted palygorskite nanocomposites

Structurally well-defined PMMA-grafted palygorskite nanoparticles were prepared by modifying the surface of palygorskite nanoparticles with initiators for reverse atom transfer radical polymerization (reverse ATRP) and by using these initiator-modified nanoparticles as macroinitiators. Reverse ATRP from palygorskite nanoparticles was then performed to attach well-defined polymer on to an inorganic core. It has been found that the dispersibility of palygorskite particles in organic solvents is significantly improved by grafting polymers onto the surface of palygorskite particles. The polymer-grafted palygorskite nanoparticles possess excellent decoloration capacity in organic solvents.     

含三唑与噻二唑Schiff碱的合成与植物激素活性研究

合成了10种三氮唑与噻二唑的新Schiff碱,讨论了它们的物理性质、UV、IR、1HNMR和元素分析.生物活性测试发现了一些化合物具有优良的植物激素活性,其中噻二唑的Schiff碱具有优良的生长素活性,而三唑的Schiff碱具有好的细胞分裂素活性和优异的生根性能.     

Construction and performance characteristics of new fentanyl-selective plastic membrane electrode.

The construction and performance characteristics of an ion-selective electrode for fentanyl-drug cation, based on an ion-pair complex with tetrakis[3,5-bis-(trifluoromethyl)phenyl]borate anion in a PVC matrix were studied. A linear response for 1 x 10(-5) mol dm-3 to 1 x 10(-2) mol dm-3 drug with a slope of 57.9 +/- 0.5 mV/decade was established. The optimum pH range was 2 to 6. The lower detection limit was 6.29 x 10(-6) mol dm-3 fentanyl citrate (2.1165 micrograms cm-3 fentanyl). There were negligible interferences from a number of inorganic cations, structural analogues, and some common drug additives in injections. The electrode proposed has been successfully applied to determine fentanyl citrate in injections. The results correlated well with those obtained by the United States Pharmacopoeia standard procedure.     

Application of step-scan FTIR to the research of quantum cascade lasers

The principle of step-scan Fourier transform infrared (FTIR) spectroscopy is introduced. Double modulation step-scan FTIR technique is used to obtain the quantum cascade laser's stacked emission spectra in the time domain. Optical property and thermal accumulation of devices due to large drive current are analyzed.     

Synthesis of an oligo(ethylene glycol)‐based third‐generation thermoresponsive dendronized polymer

An improved strategy to synthesize oligo(ethylene glycol)‐based secondary generation (G2) dendron is presented. The overall synthesis efficiency increased by 50% when comparing to the previous method, and the product purification by column chromatography becomes much easier. Based on this approach, the synthesis of the third‐generation (G3) dendrons and the corresponding methacrylate‐based G3 macromonomer becomes feasible. Because of the oil characteristics of this macromonomer, its polymerization was able to be conducted in bulk with AIBN as the initiator. The polymerization degree of the third‐generation dendronized polymer ( PG3 ) was found to be around 16 based on GPC measurement. The thermally induced dehydration processes of this polymer were monitored by temperature‐varied proton NMR spectroscopy, and its thermoresponsive behaviors were investigated with turbidity measurements using UV–vis spectroscopy. Similar to the lower generation counterparts, this threefold branched dendronized polymer also shows characteristic fast and sharp phase transitions around its apparent lower critical solution temperature. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6630–6640, 2009     

Investigation of the thickness of Ag, AgI films in the capillary for hollow waveguides

A metallic (Ag)–dielectric (AgI) hollow glass waveguide is a promising and flexible fiber for the delivery of high-power CO₂ laser radiation. The thickness of metallic (Ag) films and dielectric (AgI) films is a critical factor which greatly influences the attenuation of the waveguides. In this paper, metallic (Ag)–dielectric (AgI) films were successfully prepared in the capillary whose inner diameter is 0.53 mm, and firstly investigated with theoretical analysis and measured by means of AES and SEM. There is good agreement between theoretical thickness and experimental results, which confirms the validity of the theoretical analysis, which makes the estimate of the thickness of both the metallic and dielectric films possible with high accuracy prior to the preparation of hollow glass waveguides. The attenuation spectra of Ag/AgI hollow waveguides shows the loss increases with the thickness of Ag, AgI films and indicates that the Ag/AgI hollow waveguide is suitable for the transmission of IR radiation.     

Crystal structure of KTi0.93Sn0.07OPO4

To reveal correlations between the atomic structure and properties of the KTi_1-x SnxOPO₄ solid solutions, single crystals of the KTi_0.93Sn_0.07OPO₄ composition were synthesized and their structure was determined. The crystals belong to the KTiOPO₄ family; orthorhombic, sp. gr. Pna2₁. The unit-cell parameters are a = 12.831, b = 6.410, and c = 10.584 Å. The partial substitution of Sn atoms for Ti atoms results in the formation of more symmetric coordination polyhedra in the structure framework and the change of the physical properties of the crystals.