Chiral separation of synthetic vicinal diol compounds by capillary zone electrophoresis with borate buffer and beta-cyclodextrin as buffer additive.

The investigation on capillary electrophoretic enantioseparation of six synthetic compounds containing vicinal diol groups has been undertaken to acquire the optimum conditions using native beta-cyclodextrin (beta-CD) as chiral selector and borate as a background electrolyte. The separation was carried out in an uncoated capillary (58.5 cm x 75 microm i.d., effective length 48.5 cm) and the effects of several important factors were investigated in detail. The results showed that beta-CD as a chiral selector exhibited good enantioselectivity and that the enantioseparation was greatly influenced by the structure of the diols, the borate concentration and the buffer pH. The optimum performance was obtained for the chiral vicinal diols under the conditions of 200 mM borate buffer of pH 9.8 containing 1.7% beta-CD at an applied voltage of 15 kV and a capillary temperature of 20 degrees C. Under the conditions, four diols were baseline separated with fast analysis time and the good theoretical plate numbers (above 10 x 10(4)) and favorable migration-time reproducibilities (RSDs below 3.0%) were obtained. The separation results were satisfactory.     

金属硫蛋白加质子常数及与Cd(II)络合常数测定

用pH计和Cd离子选择电极测定了金属硫蛋白的加质子常数及其与Cd(Ⅱ)的络合常数, 用改进的简化络合模型处理实验结果, 得到了去金属硫蛋白(apo MT)中6类不同的加质子基团的数目及其加质子常数。对Cd(Ⅱ)滴定数据的计算表明, MT中两个结构域——α和β对Cd(Ⅱ)的络合常数相差约1000倍。从热力学定量描述了MT中两个结构域结合金属离子选择优先顺序。     

Click Chemistry: Evolving on the Fringe

The article herein briefly introduces the story of the birth of click chemistry and its evolution after that. A new angle to interpret click reactions was proposed using the “reactivity‐availability‐functionality” trilogy. CuAAC (Copper‐catalyzed azide‐alkyne cycloaddition), the most popular click reaction by far, was revisited along with the thiol‐ene, metal‐free AAC, SuFEx (Sulfur(VI) fluoride exchange) and the lately discovered diazotransfer process. By encountering more and more near‐perfect reactions, click chemistry is evolving and expanding on the fringe of the chemistry and different scientific disciplines, destination unknown.      

新显色剂4,4''''-对偶氮苯重氮氨基偶氮苯光度法测定溴化十六烷基三甲铵

研究了新显色剂4,4'-对偶氮苯重氮氨基偶氮苯与溴化十六烷基三甲铵(CTMAB)的显色反应.结果表明,在0.5mol·L-1 NaOH介质中,显色剂与CTMAB发生灵敏的显色反应,形成11的紫红色缔合物,其最大吸收波为575 nm,表观摩尔吸光系数为5.02×104L·mol-1·cm-1,CTMAB的含量在0～100μg/25 mL范围内遵守比耳定律.据此建立了水中微量CTMAB的光度测定方法.该法是目前测定微量CTMAB的高灵敏方法之一.在EDTA存在下,显色反应具有良好的选择性,可直接用于环境水样的分析.     

锐钛矿型纳米TiO2介孔粉体表面织构的研究

以硫酸钛和尿素为原料,聚乙二醇-1000为空间构造剂,104℃下经尿素水解均匀沉淀法研制颗粒分散均匀、粒径可控的高热稳定性锐钛矿型纳米TiO2介孔粉体,并对其晶相、颗粒大小、比表面积、形貌和孔道结构进行了表征.结果表明,未经任何热处理的TiO2粉体即为锐钛型晶相,颗粒为均匀分散的类球型颗粒,且颗粒间形成直通型的介孔孔道,其孔径在10～30nm之间.控制焙烧温度可以达到控制颗粒大小及形貌的目的,经850℃焙烧5h的样品仍保持锐钛矿型晶相,未出现向金红石型晶相转变的迹象.     

STUDY ON THE SYNTHESIS OF A NEW TYPE OF PHOSPHORUS HETEROCYCLIC COMPOUNDS-PYRAZOLO[3, 4-d]-1, 3, 2-DIAZAPHOSPHORIN-6-ONE

1-substituted-5-benzoylamino-4-pyrazolecarboxamides(2)were prepared by the reaction of 1-substituted pyrazolo[3, 4-d]-oxazinone(1)with amines in benzene.The compound 2 was refluxed with excess LiAlH₄ in a mixture of THF and ether, one of the two carbamoyl groups in the molecule 2 was reduced selectively.As the results, 1-substituted-5-benzylamino-4-pyrazolecarboxamides (3) were obtained.Compounds 3reacted with Cl₂PPh-X, or P(NET₂)3, producing the title compounds(4).The conditions of the reactions were studied.     

The complexation of apo-metallothionein with cadmium ion and its conformation study

The circular dichroism was used to study the complexation of two isoforms of rabbit liver apo-metallothioneins (apo-MT1 and apo-MT2) with Cd²⁺ ion and the influence of Cd²⁺ ion on the conformation of reconstituted MTs. The stability of sulfhydryls of apo-MT has been investigated at the room temperature in the presence of air. The reconstitutions of apo-MT1 with Cd²⁺ ion were carried out atpH 4.71 (stable state) andpH 7.9 (with 90% sulfhydryls oxidated) respectively. it was found that the characteristic CD band at 257 nm(+), 238 nm(?), 226 nm(+) of reconstituted MT with Cd²⁺ ion was the same as native MT atpH 4.71, however only one peak at 243 nm(+) appeared on the CD spectra atpH 7.9 which arose from mononuclear complexes with four separated thiolate ligands per Cd²⁺ ion. The CD spectra of apo-MTs+7 eq Cd²⁺ system were measured at variouspH values. It was found that the peak at 256 nm of apo-MT1 binding Cd²⁺ ion split into two small peaks atpH between 2.42 and 3.02, and became one peak atpH 3.32, while the shapes of Cd peaks of apo-MT2 binding Cd²⁺ ion did not change withpH, indicating that the binding sites and pathway of apo-MT1 binding Cd²⁺ ion were different from those of apo-MT2. A possible mechanism was suggested.     

若干中性配体对Mo—Fe—S簇合物自兜的影响

通过电子吸收光谱的变化研究了一些含N和含P中性配体对MoS_4~(2-)-nFeCl_2-DMF体系形成立方烷型Mo-Fe-S簇合物的可能影响。     

Fixed-bed adsorption of carbon dioxide/methane mixtures on silicalite pellets

The adsorption of carbon dioxide and methane on silicalite pellets packed on a fixed bed has been studied. Equilibrium and kinetic measurements of the adsorption of carbon dioxide and methane have been performed, and a binary adsorption isotherm for carbon dioxide/methane mixtures has been obtained. A model based on the LDF approximation for the mass transfer has been used to describe the breakthrough curves obtained experimentally. A PSA cycle has been proposed for obtaining methane with purity higher than 98% from carbon dioxide/methane mixtures containing 38% and 50% methane, and its performance has been simulated using the proposed model. The simulation results show that silicalite can be a suitable adsorbent for employment in a PSA separation process for carbon dioxide removal from coalseam and landfill gases.     

New benzo[b]furans as electroluminescent materials for emitting blue light

[structure: see text] New functionalized mono- and bis-benzo[b]furan derivatives were synthesized and developed as blue-light emitting materials. They possessed a CN, CHO, CH=CHPh, CH=CPh(2), or CH=CHCOOH group at the C4-position. Two benzo[b]furan nuclei in bis-benzo[b]furan derivatives were connected by a divinylbenzene bridge. With good volatility and thermal stability, bis-benzo[b]furan 7a was fabricated as a device. It emitted blue light with brightness 53430 cd/m(2) (at 15.5 V) and high maximum external quantum efficiency 3.75% (at 11 V).