The first systhesis of a chromia-pillared layered niobate with porosity, acidity and high thermostability

Although the hydrated niobic acid is an unusual solid acid and making an impact onits application in catalysis, it is usually nonporous and has a rather low surface area andweak acidity upon heat treatment. To overcome these shortcomings, the layered nio-bate had been pillared with thermostable inorganic oxides such as alumina and silica.Chromia is also a suitable inorganic oxide which can be used as pillar and contributesnew properties to the resultant materials. Here, we report the first synthesis of achromia-pillared layered niobate with porosity, acidity and thermostability.

Synthesis and Physicochemical Properties of L-(+)-a-(Positive Butyl)-Leucine Ethyl Ester Chiral Ionic Liquids

L-（＋）-α-（positive butyl）-leucine ethyl ester bromide chiral ionic liquid was synthesized by using microwave-assisted synthesis method and L-（＋）-α-（positive butyl）-leucine ethyl ester terafluoroborate and hexafluorophosphate chiral ionic liquids were synthesized by the anion exchange reaction. The structures were characterized by IR, ~1HNMR and structure optimization calculation. The results of studies on physicochemical properties show that they possess better thermal stability, solubility, bio-solubility and high conductivity. They can serve as effective reaction media as well as chiral catalysts. They are presently being investigated as dispersion agents in molecular imprinting ployer.

^(60)Co-γ辐照对中国仓鼠卵巢成纤维细胞DNA和组蛋白合成的影响

本文介绍了^(60)Co-γ辐照对同步的和非同步的CHO细胞的DNA合成和组蛋白合成关系的影响的研究,用~3H-胸腺嘧啶核苷和^(14)C-丙氨酸双标记,未经辐照的和经4Gy～60Gy ^(60)Co-γ辐照的CHO细胞,通过~3H和^(14)C的参入来估价DNA和组蛋白的合成,并用聚丙烯酰胺凝胶电泳鉴定辐照前后组蛋白各组分的变化情况,实验表明: 1)、在4～60Gy剂量范内,无论是同步的还是非同步的CHO细胞其DNA合成和组蛋白合成都受到不同程度的抑制。2)、在辐照后1—3小时,DNA合成和组蛋白合成都受到不同程度的抑制,但辐照后4小时,DNA合成被进一步抑制而组蛋白的合成却逐渐恢复正常,到辐照后48小时组蛋白的合成几乎接近对照水平。3)、16Gy ^(60)Co-γ辐照后8小时,非同步的CHO细胞的DNA合成被抑制的情况比G_1期CHO细胞更为严重。4)、16Gy ^(60)Co-γ辐照S期细胞,在辐照后1—24小时中DNA合成被明显抑制的同时,组蛋白的合成也受到相应的抑制。5)、从未经辐照的和经6、16和60Gy^(60)Co-γ辐照的CHO细胞分别提取全组蛋白,进行聚丙烯酰胺凝胶电泳,从电泳图谱的变化清楚地看到组蛋白H_1和H_3受辐照影响大于组蛋白H_4和H_(2B)+H_(2A),因此我们推测DNA合成和组蛋白H_1和H_3的关系较之组蛋白H_4和H_(2A)+H_(2B)更为密切。

Synthesis and Characterization of Diorganotin Compounds {[R_2Sn(ON=CHC_6H_5)]_2O}_2 and Crystal Structure of {[(C_6H_5CH_2)_2Sn(ON=CHC_6H_5)]_2O}_2

Diorganotin compounds {[R2Sn(ON=CHC6H5)]2O}2 [R=C6H5CH2 (1), 2-FC6H4CH2 (2), 4-FC6H4CH2 (3), 2-ClC6H4CH2 (4), 4-ClC6H4CH2 (5)] were synthesized by the reaction of R2SnO with HON=CHC6H5 in 1∶1 mo-lar ratio in refluxing anhydrous benzene or toluene. They were characterized by elemental analysis, IR, 1H NMR and 119Sn NMR spectroscopy. And two sets of 119Sn chemical shifts were observed in the 119Sn NMR spectra of these compounds, indicating the presence of two types of environment around the tin atoms. The crystal structure of compound 1 was determined by X-ray single crystal diffraction analysis. The results showed that the crystal of com-pound 1 belongs to a monoclinic system with space group P21/c and unit cell dimensions: a=1.0718(9) nm, b=1.9666(17) nm, c=2.0480(17) nm, =96.4371(14)? Dc=1.450 g/cm3, Z=2, F(000)=1888, V=4.290(6) nm3, =1.206 mm-1, R1=0.0405, wR2=0.0786. The compound 1 belongs to centrosymmetric dimer structure mode with a four-membered central endo-cyclic Sn2O2 unit in which the bridging oxygen atoms are tri-coordinated. Each bridging oxygen atom also connects with an exo-cyclic tin atom. The endo- and exo-cyclic tin atoms are both five-coordinated, and have coordination geometry of distorted trigonal bipyramid.

Synthesis and mesomorphic behaviour of 4'-methoxyphenyl 4"-[(4-n-alkoxy-2,3,5,6-tetrafluorophenyl) ethynyl] benzylethers

A novel homologous series of 4'-methyoxyphenyl 4'-[(4-n-alkoxy-2,3,5,6-tetrafluoro-phenyl]benzyl ethers have been prepared via Pd-catalysed Heck reactions. Polarizing microscopic textural observation shows that these compounds exhibit enantiotropic nematic phases.