Alcohols solubilization in a nonionic fluorinated surfactant based system: effects on the characteristics of mesoporous silica

In this study, we have used hydrogenated alcohols with different chain lengths and one fluorinated alcohol as additives to determine their effect on the characteristics of mesoporous materials prepared from fluorinated micelles.     

Novel coordination frameworks incorporating the 4,4'-bipyrazolyl ditopic ligand

The reaction of the rigid spacer 4,4'-bipyrazole (H(2)BPZ) with late transition metals, either following conventional routes or under solvothermal conditions, afforded the coordination polymers [M(BPZ)]·Solv (M = Zn, 1; Co, 2; Cd, 3; Hg, 4; Cu, 5; Ni, 6; Pd, 7; Solv = DMF, 3; MeCN, 5 and 6; H(2)O, 7), [Cu(H(2)BPZ)(2)(NO(3))(2)] (8), and [Cd(H(2)BPZ)(CH(3)COO)(2)] (9). State-of-the-art laboratory powder diffraction methods allowed to disclose the isomorphous character of 1 and 2, as well as of 5 and 6, which feature 3D porous networks containing 1D channels of square and rhombic shape, respectively. 3, crystallizing in the relatively rare P6(1)22 space group, consists of homochiral helices of octahedral Cd(II) ions, packing in bundles mutually linked by "radial", nonplanar BPZ ligands. Finally, the dense species 8 and 9 contain parallel 2D layers of square and rectangular meshes, respectively. Thermogravimetric analyses witnessed the relevant thermal robustness of all the [M(BPZ)] materials [except the mercury(II) derivative], which are stable in air at least up to 300 °C, with the zinc(II) derivative decomposing only around 450 °C. Variable-temperature powder diffraction experiments highlighted the permanent porosity of 1-3, 5, and 6, retained along consecutive temperature cycles in all cases but 3. When probed with N(2) at 77 K, 1-3 and 5-7 showed Brunauer-Emmett-Teller and Langmuir specific surface areas in the ranges 314(2)-993(11) and 509(16)-1105(1) m(2)/g, respectively.     

Solubilization of various fluorocarbons in a fluorinated surfactant/water system: relation with the design of porous materials

We have investigated the phase behavior of the R(F)(7)(EO)(8) surfactant in water as well as the effect of the solubilization of various fluorocarbons in this system. Results show that the cloud point (CP) curve is shifted to high temperatures upon addition of fluorocarbons, following the sequence 1-bromo-perfluorooctane (PFOB) < perfluorodecalin (PFD) < perfluorooctane (PFO). The values of the phase inversion temperature (PIT) associated with these systems increase in the same order: PFOB approximately 65 degrees C, PFD approximately 82 degrees C, and PFO > 90 degrees C. Starting from these systems, we have prepared mesoporous and hierarchical porous materials. The formation of the ordered mesoporous materials has been related to the CP curve. Indeed, our results show that mesoporous materials with a high degree of ordering are obtained from systems whose CP curve is shifted toward high temperatures. We have also correlated the formation of the hierarchical porous silica to the PIT. It appears that the design of macro-mesoporous materials is favored with systems that exhibit a high value of the PIT.     

基于柔性硫代二乙酸配体的镧系配位聚合物的合成、结构和荧光性质

利用硫代二乙酸配体[thiodiacetic acid = H2tda]与稀土盐[SmCl3·nH2O,DyCl3·nH2O]反应合成了两种新型稀土配合物[Ln2(tda)3(H2O)2]n (Ln = Sm(1), Dy(2)),单晶结构分析表明：两个配合物结构相同,均是通过以共边多面体[Ln2O16]为基本单元的一维稀土金属链拓展而成的二维层状结构。有趣的是,在配合物中,硫代二乙酸配体展现了两种配位模式：双“顺-顺桥式双齿、螫合-桥式三齿”模式和双“螯合-桥式三齿、顺-反桥式双齿”模式;正是通过配体这两种配位方式的连接,上述一维稀土金属链扩展为具有(3,4,5,6)连接(47·68)(44·66) (45·6)(46)(43)拓扑结构的二维网络。荧光性质研究表明,在室温下镝配合物呈现黄色荧光,钐配合物呈现鲑鱼粉色荧光。     

通过阳离子的部分氯化和氟化提高离子液体的憎水性

报道了一类咪唑环阳离子上同时含有氯和氟元素的新型离子液体,即 和 。这类离子液体是将其前驱体甲基丁基咪唑氯盐或甲基丁基咪唑六氟磷酸盐经过氯化取代和氟化取代反应来制备的。采用氢核磁共振谱（1H-NMR）确定了氯化反应过程中氯取代氢的位置,结果表明,氯主要取代咪唑环上的氢以及部分丁基侧链上甲基基团中的氢。考察了这类离子液体的水溶性,热稳定性以及黏度。结果表明,离子液体经氯化和氟化处理可以显著提高其憎水性。     

酸性离子液体催化的羟基化合物对N-对甲苯磺酰基氮杂环丙烷的开环反应

本文研究了羟基化合物对两种类型N-对甲苯磺酰基氮杂环丙烷的开环反应。在功能性离子液体[hmim]HSO4存在条件下,氮杂环丙烷与醇反应,以中等到高的产率和非常高的区域选择性得到对应的β-胺基醚。并且离子液体[hmim]HSO4可以循环使用。     

基于镱和铒的α-噻吩甲酰丙酮-哌啶配合物与DNA之间相互作用的DNA探针和切割研究

两种[Ln(TTA)4].HP (Ln =Yb, Er)配合物被合成并表征。通过紫外可见光谱、荧光光谱、粘度和分子模拟研究了他们与DNA的键合特征。研究结果表明：它们能插入双链的DNA。更重要的是它们的荧光强度能被DNA增强,因此,一种灵敏的荧光检测DNA的方法被发展。两种配合物与质粒DNA的切割反应在凝胶电泳上展开。有意义的是,我们发现在pH=7.2 和 37℃下,两种化合物都能切割超螺旋质粒DNA。另外,我们选择BDNPP作为模型化合物进一步研究了它们对质粒DNA的切割机理,从一级动力学方程,我们间接证明可能是水解切割机理。     

人工神经网络紫外光度法同时测定甲基苯甲醛的三种同分异构体及其与偏最小二乘法的比较

同分异构体的同时测定一直是分析化学领域的热点和难点问题,本文将化学计量学中的多元校正方法,如偏最小二乘法和人工神经网络法与紫外分光光度法相结合,同时测定了紫外吸收光谱严重重叠的甲基苯甲醛的三种同分异构体混合体系中各组分的含量。确定了测定的最佳波长范围为230～304 nm;测得48个混合标样的吸光度值用于建立模型,其中,邻、间、对甲基苯甲醛的浓度范围分别为6.0～15.0、7.0～16.0和8.0～19.0 μg·mL-1。7个模拟样品作为监测集用于检验所建立模型的预测性能。本文还讨论了三种组分浓度比例对所建立模型预测性能的影响并确定了可以准确测定的浓度比例范围。所建立的方法用于模拟样品的测定,其回收率在84.00%与109.60%之间。与偏最小二乘法的测定结果比较,经成对t检验表明,两种方法对邻、间甲基苯甲醛测定结果无显著性差异;而对甲基苯甲醛的测定,人工神经网络法的测定结果优于偏最小二乘法。     

灰色链霉菌ATCC 13273 位点特异性转化商陆皂苷元羟基化反应研究

为增加商陆皂苷元的结构多样性,本研究采用两步培养法,利用灰色链霉菌ATCC 13273对其进行生物转化,得到一个极性增大的羟基化产物。通过二维核磁、高分辨质谱等方法鉴定该转化产物为2β, 3β, 23, 29-四羟基-齐墩果烷-12-烯-28, 30-二酸-30-甲酯。     

Pd/C/PPh3:简单有效的双羰化反应催化体系

碘代芳烃与二乙胺在Pd/C催化作用下成功的合成了α-酮酰胺,可以得到非常不错的收率和选择性。在最佳反应条件下,对于不同的碘代芳烃和二级胺都很有很好的底物适应性。