2,4,6-三硝基苯酚改性锆铝复合氧化物固定相分离富勒烯的色谱性能研究

制备了用于分离C60和C70的2，4，6－三硝基苯酚改性锆铝复合氧化物高效液相色谱固定相，考察了流动相中甲苯的含量、柱温及流速对C60和C70分离的影响，同时比较了酸腐蚀前后锆铝复合氧化物基质对分离的影响，结果表明，2，4，6－三硝基苯酚改性酸腐蚀后锆铝复合氧化物填料对富勒烯表现出较强的分离能力，具有作为富勒烯制备分离的潜力。     

表面修饰二氧化锡纳米微晶的制备与表征

制备了硅烷偶联剂KH-570表面修饰的SnO2纳米微晶，通过FT-IR、XPS、TEM和TG-DTA对其结构和表面特性进行表征和研究. FT-IR和XPS分析结果确证了KH-570与SnO2表面是以化学键合或物理吸附方式相结合,粒子表面存在酯基等有机官能团的红外吸收特征；观测到KH-570中Si原子的Si2s和Si2p谱线. TEM分析表明，表面修饰反应增强了SnO2纳米微晶的疏水性和分散性.由XPS和TG的实测数据探讨了纳米粒子具有较低包覆量的可能原因.     

An <Emphasis Type="BoldItalic">in silico</Emphasis> approach for screening flavonoids as P-glycoprotein inhibitors based on a Bayesian-regularized neural network

Summary P-glycoprotein (P-gp), an ATP-binding cassette (ABC) transporter, functions as a biological barrier by extruding cytotoxic agents out of cells, resulting in an obstacle in chemotherapeutic treatment of cancer. In order to aid in the development of potential P-gp inhibitors, we constructed a quantitative structure–activity relationship (QSAR) model of flavonoids as P-gp inhibitors based on Bayesian-regularized neural network (BRNN). A dataset of 57 flavonoids collected from a literature binding to the C-terminal nucleotide-binding domain of mouse P-gp was compiled. The predictive ability of the model was assessed using a test set that was independent of the training set, which showed a standard error of prediction of 0.146 ± 0.006 (data scaled from 0 to 1). Meanwhile, two other mathematical tools, back-propagation neural network (BPNN) and partial least squares (PLS) were also attempted to build QSAR models. The BRNN provided slightly better results for the test set compared to BPNN, but the difference was not significant according to F-statistic at p = 0.05. The PLS failed to build a reliable model in the present study. Our study indicates that the BRNN-based in silico model has good potential in facilitating the prediction of P-gp flavonoid inhibitors and might be applied in further drug design.     

Elutionseigenschaften des Ethylendiamins zur ionen-chromatographie von metallionen

(Elution characteristics of ethylenediamine in ion-chromatography of metal ions). Studies are reported on the action of ethylenediamine with citric or oxalic acid in the eluent on separations of heavy metals, magnesium and alkaline earth elements on columns of Nucleosil SA-10 and Dionex CS-2. The effect of ethylenediamine on the retention times of the alkaline earth elements and manganese is greater than that of the two organic acids, whereas these organic acids have a greater effect on the retention times of heavy metals. This regularity is useful in separations of the heavy metals and alkaline earth elements.     

Synthesis and magnetic properties of trinuclear nickel(II) complexes bridged by α-benzyldioximato groups

Four new NiII–NiII–NiII homotrinuclear complexes namely [Ni(-BD)2{NiL2}](ClO4)2 [L = 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (5-NO2-phen), 2,2-bipyridyl (bpy) or 4,4-dimethyl-2,2bipyridyl (Me2bpy) and (-BD)– = -benzyldioximato ion] have been prepared and characterized. Based on elemental analyses, i.r. spectra, conductivity measurements, extended -benzyldioximato-bridged systems consisting of three nickel(II) ions in which the central nickel(II) ion has a square-planar environment and the end capped two nickel(II) ions have a distorted octahedral environment are proposed for these structures. The temperature dependence of the magnetic susceptibility for complexes (1) (phen), (2) (5-NO2-phen), (3) (bpy) and (4) (Me2bpy) were measured over the 77–300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator (H^ = –2JS^1S^2), giving the exchange integral J = –13.31 cm–1 for (1), J = –7.37 cm–1 for (2), J = –8.96 cm–1 for (3) and J = –7.33 cm–1 for (4) These results indicate a weak antiferromagnetic spin exchange interaction between the two terminal nickel(II) io     

负载型催化剂制备的聚丙烯等规度分布

负载型Ziesler－Natta催化剂中存在许多活性中心［'3，为了解其本质，需对其各自产生的聚合物进行分离，以往采用的溶剂抽提法［'－'j只能将聚合物大致分级．最近，升温淋洗分级法（TREF）已被运用于聚丙烯的分级卜，'，其原理是根据聚合物的结晶度分级D'，影响聚丙烯结晶性的主要因素是等规度，而分子量到达一定程度后其影响较小，故通过TREF分级可得到聚丙烯的等规度分布．TREF法的淋洗温度可控，故分级效果较好．该法在分级前需对样品进行等温结晶处理，以消除抽提法由于样品未必充分结晶而带来的误差．本文用TREF法对不同催化…     

Self-assembling a molecular pegboard

This paper describes the design, construction, and application of a self-assembled, chemically addressable DNA nanogrid composed of DNA tiles of nanometer dimensions. This self-assembled structure permits precise placement of molecules at predetermined locations on a "molecular pegboard". We used the indexed DNA nanogrids to identify single molecules of DNA that hybridize at particular locations.     

手性双氨基醇-Et2Zn催化的不对称直接羟醛缩合反应

以1,3-二溴丙酮和(2'S)-(二苯基羟甲基)-四氢吡咯为原料,合成了两种新型手性氨基醇1,3-双[(2'S)-(二苯基羟甲基)-1-四氢吡咯基]丙酮(3)和1,3-双[(2'S)-(二苯基羟甲基)-1-四氢吡咯基]-2-丙醇(4),总产率分别为39%和35%.手性双氨基醇3-/4-Et2Zn可催化未修饰醛、酮的不对称直接羟醛缩合反应,对映体过量最高9%.     

Synthesis and Characterization of Dual Acidic Ionic Liquids

Novel ionic liquids with dual acidity, of which the cation contains Brφnsted acidity and anions contain Lewis acidity were synthesized. These ionic liquids obtained were identified by NMR, FF-IR, SDT and FAB-MS. Their acidities were determined by pyridine probe on IR spectrography.     

A facile synthesis of 2-substituted-2,3-dihydro-4(1H)-quinazolinones in 2,2,2-trifluoroethanol

2-Substituted-2,3-dihydro-4(1H)-quinazolinones were obtained in high yields by condensation of anthranilamide with aryl, alkyl or heteroaryl aldehydes or ketones in the refluxing 2,2,2-trifluoroethanol without any catalyst.