Farnesic acid glycerides from the nudibranch Archidoris odhneri

The dorid nudibranch Archidoris odhneri produces (all E)-2,3-dihydroxypropylfarnesate and its two monoacetoxy derivatives.     

NO2气相硝化金刚烷的计算研究

运用密度泛函理论(DFT)和半经验MO-PM3方法研究了NO₂气相硝化金刚烷反应机理. 计算结果表明, NO₂不能直接取代金刚烷H; 在B3LYP/6-311＋＋G(3df,2pd)//B3LYP/6-31G* 较高水平下, 对三个可能机理的反应势垒(E_a)的精确计算表明, 该反应的决速步骤为NO₂中O和N进攻1-H的竞争过程, 且1-硝基金刚烷为主要产物. NO₂中O进攻1-H决速反应过程中, 分子几何、原子自然电荷及IR光谱变化表明, C—H键的断裂和N—H键的形成是一个协同过程; 参与新键形成和旧键断裂原子C(1), H(11), O(28), O(29)和N(27)的原子自然电荷及与其相关的键长、键角有明显的变化. 反应过程中体系偶极矩的变化表明, 极性溶剂能降低反应势垒, 有利于反应的进行.     

基于G-四链体-氯化血红素DNA酶比色法测定银离子和汞离子传感器的构筑

利用G-四链体DNA(5′-CTGGGAGGGAGGGAGGGA-3′)与氯化血红素结合形成G-四链体-Hemin DNA酶,其能高效催化H_2O_2氧化反应底物由无色变为绿色,当溶液中有Ag~+或Hg~(2+)存在时会阻碍该DNA酶的形成,导致绿色溶液变浅。基于此,建立了比色法测定Ag~+和Hg~(2+)的传感器。在最佳实验条件下,溶液的吸光度与Ag~+和Hg~(2+)浓度分别在100.0～1 000.0 nmol/L和80.0～800.0 nmol/L范围内具有良好的线性关系,检出限(3δ/Slope)分别为55.9 nmol/L和64.3 nmol/L。该方法具有较好的选择性,采用该方法对实际样品进行测试,结果满意。     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速筛查染发剂中32种染料成分

建立了超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速筛查和分析染发剂中32种禁限用染料的分析方法。样品经甲醇-2 g/L抗坏血酸水溶液溶解提取,正己烷净化,用ZORBAX Eclipse Plus C_(18)(3.0 mm×100 mm,1.8μm)色谱柱分离,以甲醇-5 mmol/L乙酸铵水溶液为流动相进行梯度洗脱,采用正、负离子切换同时测定了32种染料成分,显著提高了检测通量。以全扫描模式下提取的保留时间和一级母离子精确质量数以及同位素丰度比,实现对染发剂中多种染料成分的快速筛查;以自动触发采集的二级碎片离子精确质量数进行确证。32种染料在相应的质量浓度范围内线性关系良好,相关系数(r~2)均大于0.99;定量下限(LOQ)为0.2～40μg/g,回收率为81.0%～110%,相对标准偏差(RSD)为3.3%～9.9%。该方法简单、准确、快速,适用于染发剂中多种禁限用染料成分的高通量快速定性筛查和定量分析。     

Orientation of Na(3p) states excited in Na-He collisions

The orientation of Na(3p) states created in 3–13 keV Na(3s)-He collisions has been studied by the polarised photon-scattered particle coincidence technique at scattering angles corresponding to the impact-parameter range 1–2 a.u. In the standard geometry, at large impact parameters the excitation process exhibits a very high degree of orientation with about 90% of the Na(3p) states havingm ₁=?1. Strong reduction in this propensity is observed at impact parameters smaller than about 1.3 a.u., where a molecular curve crossing causes simultaneous He(n=2) excitation. In this region, also ionisation becomes important.     

Infrared and Raman spectroscopic investigations of the Nb(V) fluoro and oxofluoro complexes in the LiF-NaF-KF eutectic melt with development of a diamond IR cell

A vacuum-tight cell for infrared spectroscopic investigations of extremely corrosive melts, e.g., molten fluorides, has been constructed and tested up to 750 degrees C. The cell has a gold-lined sample chamber and a diamond window transparent for the infrared light. It can be furnished with a gold piston that enables the recording of short-path-length FTIR spectra of liquid samples. Solutions of Nb(V) in LiF-NaF-KF eutectic (FLINAK) with and without oxide additions have been investigated by FTIR and Raman spectroscopy. The presence of NbF7(2-), NbOF5(2-), and NbO2F4(3-) complexes was established in the molten state at 600 degrees C. After solidification NbF7(2-) was still the only Nb(V) all-fluoro complex present. Three oxofluoro complexes, NbOF6(3-), NbOF5(2-), and NbO2F4(3-), have been identified in the solid state. Typical frequency regions for the different complexes are established. Finally, it was shown that K2NbF7 can be used as an indicator to determine the oxide content of the sample melts.     

杂原子钛对TiY分子筛性能的影响

采用水热晶化法合成了含骨架杂原子的TiY分子筛，通过X射线粉末衍射（XRD）、傅里叶变换红外光谱(FT-IR)、差示扫描量热、吡啶吸附红外光谱等方法考察了杂原子Ti进入Y分子筛骨架后对分子筛各项性能的影响。结果表明，TiY分子筛具有典型的Y型分子筛晶体结构；随着Ti添加量的增加，TiY分子筛晶化所需的时间延长，晶胞常数增大，分子筛的热稳定性和水热稳定性均有所增强。与Y分子筛相比， TiY分子筛的L酸中心数量明显增加，同时B酸中心强度增加，TiY分子筛的裂化反应活性提高，催化剂上的积炭量明显减少。     

Diagrammatic formulation of the kinetic theory of fluctuations in equilibrium classical fluids. V. The short time approximation for the memory function

The correlation function for density fluctuations in a monatomic fluid obeys a formally exact kinetic equation containing a memory function. A previously derived short time approximation (STA) for this memory function is tested by comparing its predictions with the results of molecular dynamic simulations of a dense Lennard-Jones fluid at a variety of temperatures. This approximation takes into account the contribution to the correlation function of uncorrelated repulsive binary collisions. The qualitative changes of predicted correlation functions with temperature and wave vector are generally correct. The major exception to this is the transverse current correlation function for small wave vector. The quantitative accuracy is better at short times than long times and better at high temperatures than low temperatures. The major failing of the STA is its underestimation of the amplitudes of the negative dips in the current autocorrelation functions and of the temperature dependence of the amplitudes of the dips. Despite its deficiencies in predicting the time dependence of current correlation functions, the STA gives accurate results for the self-diffusion coefficient and the shear viscosity coefficient at the highest temperatures studied.     

Synthesis, resolution, and applications of 2, 2'-bis(diphenylphosphino)-3,3'- binaphtho[2,1-b]furan

[structure: see text] A short five-step synthesis of (+/-)-2,2'-bis(diphenylphosphino)-3, 3'-binaphtho[2,1-b]furan (BINAPFu, 1) starting from 2-naphthoxyacetic acid is reported. The resolution of BINAPFu 1 was possible using our newly developed resolution procedure for phosphines wherein (1S)-camphorsulfonyl azide was used to prepare the bisphosphinimine of BINAPFu via the Staundinger reaction. BINAPFu consistently outperformed BINAP in an asymmetric Heck reaction between 2,3-dihydrofuran and phenyl triflate.