Well‐Defined Silica‐Supported Calcium Reagents: Control of Schlenk Equilibrium by Grafting

Bound to stay heteroleptic : Grafting of homoleptic benzyl and amide calcium reagents onto silica affords well‐defined supported heteroleptic species, catalytically active in hydrosilylation, hydroamination, and styrene polymerization. The fact that attempts to generate a molecular model were thwarted by the Schlenk equilibrium affording the homoleptic compound (see scheme) emphasizes the importance of immobilization as an approach for the syntheses of heteroleptic calcium complexes.

     

Influence of mesoporous structure type on the controlled delivery of drugs: release of ibuprofen from MCM-48, SBA-15 and functionalized SBA-15

Ordered mesoporous materials exhibit potential features to be used as controlled drug delivery systems, including their wide range of chemical compositions and their outstanding textural and structural properties. Therefore, it is possible to control the drug release kinetics by tailoring such parameters. In this paper, mesoporous materials such as MCM-48 and SBA-15, which present different pore sizes (3.7 and 8.8 nm) and structural characteristics (3D-bicontinuous cubic and 2D-hexagonal, respectively) have been synthesized to evaluate their application as drug delivery system and to determine their influence on release kinetic of ibuprofen. Moreover, a chemical modification of the SBA-15 mesoporous material with octadecyltrimethoxysilane has also been performed to study its influence on the release rate of ibuprofen. The structural characteristics (3D cubic and 2D hexagonal pore system) do not affect the release kinetic profiles of ibuprofen. On the contrary, the pore size affects highly to the release kinetic profiles from first-order kinetic to zero-order kinetic for MCM-48 and SBA-15, respectively. Moreover, the importance of surface functionalization was demonstrate through the very fast delivery of ibuprofen from SBA-15 mesoporous materials functionalized with octadecyl chains.     

Synthesis, structure and adsorption properties of nanoporous SBA-15 materials with framework and surface functionalities

Highly ordered SBA-15 nanoporous silica containing ethylene, phenylene bridges or/and amine, thiol, vinyl and phenyl surface groups were synthesized by using amphiphilic block copolymer as the structure-directing agent. The XRD data shows high degree of the order of the final structures. Obtained materials have well-developed porous structure—values of specific surface area are in the range 700–1050 m²/g and the sizes of cylindrical mesopores are in the range 6.5–9.5 nm. It was determined that size of the mesopores strongly depends even on small amounts of co-monomers co-condensing with TEOS. A new technique to introduce some amount of pendant amine groups by co-condensation of proper monomers has been proposed. Tetragonal structure was obtained when small amount of vinyl groups was introduced to the system. A new approach of determining pore size based only on the XRD measurements was compared with KJS method, confirming full usefulness of the former for calculation of the size of mesopores in SBA-15 materials. Dedicated to Professor Mietek Jaroniec on the occasion of his 60th birthday.     

Controllable Synthesis of Mesoporous Co3O4 Nanostructures with Tunable Morphology for Application in Supercapacitors

Flower power : Various mesoporous Co₃O₄ architectural structures (see figure) have been successfully prepared through a facile binary‐solution route and sequential thermal decomposition at atmospheric pressure. The electrochemical experiments showed that the specific capacitance of Co₃O₄ nanosheets was higher than that of Co₃O₄ microspheres in a KOH electrolyte.

     

含多壁碳纳米管的硅胶整体柱的制备、表征及性能评价

制备了一种新的含多壁碳纳米管的硅胶整体柱,并用扫描电子显微镜和比表面积测试仪对其进行了表征.利用正己烷为流动相,考察了该整体柱的流速与渗透率和流速与柱压降的关系,以及苯取代化合物在该整体柱上的色谱保留行为,并对其在分离过程中的作用机理进行了探讨.     

锐钛相介孔SO42-/TiO2的声化学制备及结构和催化酯化性能

不使用有机模板剂,采用超声化学法一步水解制得吸附硫酸根的介孔偏钛酸,500℃焙烧得到介孔SO2-4/TiO2固体超强酸.用XRD、TFEM、FTIR、低温氮吸附-脱附等手段对催化剂结构进行了表征.结果表明,硫酸根在焙烧过程中与前驱体介孔偏钛酸孔壁上自由羟基的键合起到了孔结构导向及支撑作用,500℃焙烧后样品具有161 m2·g-1的比表面积及4.1 nm的平均孔径,酸强度H0介于-14.52与-16.02之间,硫含量为2.8%,晶型全部为锐钛矿相,介孔SO2-4/TiO2具有较大比表面、强酸特性和稳定性.催化合成富马酸二甲酯的最佳条件为:n(甲醇):n(富马酸)=6:1,催化剂用量为1.0%(反应物总质量),带水剂苯用量为10 mL,反应时间为3 h,催化剂重复使用7次,酯化率大于90%.     

磷酸铝镍介孔催化材料的低热固相合成及形成机理

以十六烷基三甲基溴化铵为模板,通过二水磷酸二氢钠、六水氯化铝与六水氯化镍的固相反应直接合成了磷酸铝镍(NiAlPO)介孔材料。用X-射线衍射、高分辨透射电镜、N₂脱附-吸附、红外光谱仪等分析技术对材料进行了物相与表面织构表征,通过电感耦合等离子发射光谱仪对材料的元素组成进行分析;探讨了磷酸铝镍介孔材料的形成机理。结果表明,金属镍已进入了磷酸铝骨架,镍的含量为5.15wt%;所得介孔材料呈蠕虫状、无定形的六面体结构;其BET比表面积为157.3 m²·g^-1,孔径分布中心为3.65和5.3 nm。P(Al)-O-Ni键伸缩振动所产生的吸收峰为983.7 cm^-1。     

Cross-aldol Condensation of Cycloalkanones and Aromatic Aldehydes in the Presence of Nanoporous Silica-based Sulfonic Acid (SiO2-Pr-SO3H) under Solvent Free Conditions

The aromatic aldehydes underwent cross aldol condensation with cycloalkanones in the presence of a catalytic amount of nanoporous silica-based sulfonic acid (SiO2-Pr-SO3H) under solvent-free conditions to afford the corresponding α,α’-bis(substituted benzylidene)cycloalkanones in excellent yields with short reaction time without any side reactions. This method is very general, simple and environmentally friendly in contrast with other existing methods. SiO2-Pr-SO3H was proved to be an efficient heterogeneous solid acid catalyst, which could be easily handled and removed from the reaction mixture by simple filtration, and also recovered and reused without loss of reactivity.     

A Novel Catalytic Method for the Oxidation of Sulfides to Sulfoxides with Silica Sulfuric Acid and Sodium Nitrite in the Presence of KBr and/or NaBr as Catalyst

Highly efficient selective oxidation of sulfides to sulfoxides by NaNO₂ and silica sulfuric acid catalyzed with KBr or NaBr has been reported. This oxidation was carried out in the presence of wet SiO₂ (50% w/w) in acetonitrile at room temperature with good to excellent yields.