Design of ordered bimodal mesoporous silica materials by using a mixed fluorinated-hydrogenated surfactant-based system

Mesoporous silica materials have been prepared using aqueous solutions of hydrogenated-fluorinated surfactant mixtures. The phase behavior of the C18H35(OC2H4)10-C6F15C2H4(OC2H4)11OH [RH18(EO)10-RF6(EO)11] mixture in aqueous solution was first established at the temperature at which the silica source is added, i.e., 20 or 40 degrees C. We have delimited the different phase domains. Concerning the mesostructured silica, whatever the temperature at which the silica source is added, mesoporous material with a hexagonal array of their channel is formed via a cooperative templating mechanism (CTM), if the content of RF6(EO)11 in the surfactant mixture is lower than 50%. Moreover, when the silica source is added at 40 degrees C, the recovered materials exhibit a bimodal pore size distribution. The appearance of this bimodality has been related to the coexistence of hydrogenated micelles with fluorinated wormlike micelles. By contrast, the bimodality is not observed when the silica source is added at 20 degrees C.     

Native red electrophoresis--a new method suitable for separation of native proteins

A new type of native electrophoresis was developed to separate and characterize proteins. In this modification of the native blue electrophoresis, the dye Ponceau Red S is used instead of Coomassie Brilliant Blue to impose uniform negative charge on proteins to enable their electrophoretic separation according to their relative molecular masses. As Ponceau Red S binds less tightly to proteins, in comparison with Coomassie Blue, it can be easily removed after the electrophoretic separation and a further investigation of protein properties is made possible (e.g. an enzyme detection or electroblotting). The tested proteins also kept their native properties (enzyme activity or aggregation state).     

Coexistence of two kinds of fluorinated hydrogenated micelles as building blocks for the design of bimodal mesoporous silica with two ordered mesopore networks

A simple and effective route has been developed for the synthesis of bimodal (3.6 and 9.4 nm) mesoporous silica materials that have two ordered interconnected pore networks. Mesostructures have been prepared through the self-assembly mechanism by using a mixture of polyoxyethylene fluoroalkyl ether and triblock copolymer as building blocks. The investigation of the R(F)(8)(EO)(9)/P123/water phase diagram shows that in the considered surfactant range of concentrations the system is micellar (L(1)). DLS measurements indicate that this micellar phase is composed of two types of micelles; the size of the first one at around 7.6 nm corresponds unambiguously to the pure fluorinated micelles. The second type of micelles at higher diameter consists of fluorinated micelles that have accommodated a weak fraction of P123 molecules. Thus, in this study the bimodal mesoporous silica is really templated by two kinds of micelles.     

Pro-porous coordination polymers of the 1,4-bis((3,5-dimethyl-1H-pyrazol-4-yl)-methyl)benzene ligand with late transition metals

Solvothermal reactions of the flexible, pyrazole-based 1,4-bis((3,5-dimethyl-1H-pyrazol-4-yl)methyl)benzene ligand (H(2)BDMPX) with late transition metal ions allowed the isolation of the four coordination compounds M(x)(BDMPX) (x = 1 for M = Zn, 1; Co, 2; Cd, 3; x = 2 for M = Cu, 4). The investigation of the thermal behavior assessed the high thermal robustness of these materials, which are stable in air at least up to 300 °C, with the Cd(II) derivative starting to decompose only around 500 °C. As retrieved by ab initio X-ray powder diffraction, the isomorphous compounds 1-3 possess a dense 3-D network featuring rhombic motifs hinged about rigid and parallel chains of tetrahedral MN(4) chromophores. As demonstrated by thermodiffractometric measurements, temperature increase triggers framework flexibility. The latter is at work also when N(2) adsorption is assayed at 77 K: 1 and 2 show permanent porosity, with BET and Langmuir specific surface areas of 515, 667 m(2)/g and 209, 384 m(2)/g, respectively. 1 and 2 thus represent an intriguing example of "porosity without pores", their pro-porous nature being explained in terms of the flexibility of the rhombic motifs, stimulated by the gas probe and facilitated by the nature of the ligand.     

Ru膜上Pt层的自发沉积及其在电化学表面增强红外光谱中的应用

采用自发沉积法在Ru膜上生成超薄Pt层(简称Ru/Pt膜), 即在开路状态下将电化学还原后的Ru膜浸于除去氧的H2PtCl6溶液中进行自发沉积. 电化学伏安法测量表明, 随着电还原-自发沉积循环次数的增加, 该Ru/Pt膜电极所含Pt组分增加, 且CO吸附层的电氧化峰电位较Pt膜电极上的明显负移. 应用现场衰减全反射表面增强红外光谱法(ATR-SEIRAS)可轻易检测到在该膜电极Pt和Ru位上吸附CO的振动谱峰. 所制Ru/Pt膜电极不仅对CO的电催化氧化具有协同效应, 还可应用于现场ATR-SEIRAS的研究中.     

Au2n-(n＝1, 2)催化CO氧化反应机理的理论研究

采用密度泛函理论B3LYP方法研究了金团簇阴离子 和 催化CO氧化反应的详细机理. 计算结果表明, O2分子比CO分子更容易吸附到金团簇上. 第二分子CO能有效降低较强O—O键断裂所需能量. CO氧化反应过程需要两个CO分子协同进行. 和 催化CO氧化反应均通过碳酸根中间体进行, 活化能分别为0.607 和0.658 eV. 和 都能在常温下有效催化CO氧化反应. 这些结果与以前的实验和理论研究一致.     

配合物[Co2(EGTB)Cl2]•(BF4)2•5H2O与DNA相互作用的研究

用紫外光谱法、荧光光谱法、黏度法、凝胶电泳法研究了双核钴(II)配合物[Co2(EGTB)Cl2]•(BF4)2•5H2O和DNA的相互作用, 在pH＝7.2的缓冲体系中, 求得配合物与DNA的结合常数. 结果表明, 配合物在接近生理条件下能有效地断裂pBR322DNA, 同时可使DNA的粘度增加, 使EB-DNA体系的荧光强度降低. 配合物与DNA的荧光光谱和紫外光谱表明, 配合物与DNA的作用既存在部分插入结合又存在静电结合模式.     

由己二酸根桥联的新颖双U形四核铜配合物: [Cu4(phen)4(NO3)2(H2O)2(adip)4/4(Hadip)4/2](NO3)2•2H2O

邻菲罗啉、己二酸和硝酸铜在水溶液中反应得到一种新颖的四核铜配合物[Cu4(phen)4(NO3)2(H2O)2- (adip)4/4(Hadip)4/2](NO3)2•2H2O (其中H2adip＝己二酸), 并经元素分析, IR, UV, TG和X射线单晶衍射分析表征. 该配合物晶体属三斜晶系, 空间群, a＝1.0146(2) nm, b＝1.0261(2) nm, c＝1.8285(4) nm, α＝91.66(3)°, β＝92.19(3)°, γ＝112.76(3)°, V＝1.7520(6) nm3, Z＝1, Dc＝1.639 g/cm3, C66H66Cu4N12O28, Mr＝1729.47, F(000)＝886, μ＝1.294 mm－1, R1和wR2分别为0.0447和0.1141. 己二酸根通过4个羧基O将两个U形双核亚单元联接成具有一个对称中心的双U形四核结构, 其中每个U型亚单元包含晶体学上不对称的2个Cu(II)原子. 每个Cu(II)离子均处于畸变的四方锥配位环境, 除与己二酸氢根(Hadip)、己二酸根(adip)和邻菲罗啉(Phen)的N, O配位形成锥底平面外, 其中的1个Cu(II)与水配位, 而另一个Cu(II)则与硝酸根配位. 配合物晶体结构中存在着广泛的氢键和p×××p作用.     

山茱萸炮制过程中环烯醚萜苷类成分的质谱研究

利用高效液相色谱-电喷雾多级串联质谱(HPLC-ESI-MSn)联用技术, 对传统中药山茱萸炮制过程中环烯醚萜苷类成分的变化进行了研究. 采用反相C18色谱柱, 二元线性梯度洗脱, 分离并获得了山茱萸中7个环烯醚萜苷类化合物. 并通过电喷雾一级质谱获得了上述7种化合物的分子量信息, 利用电喷雾质谱的源内碰撞诱导解离技术, 获得了该类化合物在负离子模式下的碎裂特征, 在此基础上, 对其进行了结构鉴定和含量分析. 首次发现了差向异构体7α-乙氧基莫诺苷和7β-乙氧基莫诺苷化合物. 研究结果表明, 当采用HPLC-ESI-MS法分析山茱萸环烯醚萜苷类化合物时, 通过色谱保留时间色谱峰面积和质谱特征两方面信息能够提供更加准确可靠的定性定量结果.