Synthesis of Mesoporous Silica Materials via Nonsurfactant Templated Sol-Gel Route by Using Mixture of Organic Compounds as Template

Mesoporous silica materials have been successfully prepared by employing a mixture of -cyclodextrin and urea as a template in a HCl-catalyzed sol-gel process, followed by extraction with water. The obtained materials are characterized by nitrogen adsorption-desorption measurements, powder X-ray diffraction patterns and transmission electron microscopy. The changes of the pore parameters depend on both the weight ratio of -cyclodextrin and urea and the template content in the final silica composite. The effects of the mixture as template (or pore-forming agent) on the physicochemical properties of the two synthesized systems, with different weight ratio and same template content, as well as varied template content and fixed weight ratio, were investigated in this paper. The results show that the hydrogen bonding interactions between -cyclodextrin and urea molecules or urea aggregates, the urea-holding -cyclodextrin molecules themselves as well as inorganic species are the driving force in the formation of mesoporous silica materials.     

Electrocatalysis of metalloporphyrins: Part 12. Chemically modified electrodes with porphyrin-incorporated Nafion coatings

The electrocatalytic behaviour of cobalt(III) tetrakis(4-trimethylammoniumphenyl)porphyrin (CoTMAP) and the electroreduction mechanisms of dioxygen and dithiodipropionic acid (PSSP) at glassy carbon electrodes (GCEs) modified with Nafion coatings incorporating CoTMAP and Ru(NH₃)₆³⁺ have been studied. The experimental results indicate that the catalytic electroreduction of dioxygen using CoTMAP as a catalyst and Ru(NH ₃)₆³⁺ as a mediator could proceed at the Nafion coating—solution interface regardless of the state of the electrode surface. The catalytic electroreduction of dithiodipropionic acid could not proceed at the Nafion coating—solution interface but only at the GCE—solution interface, suggesting the importance of the adsorption of Co(I)TMAP on the GCE to the catalytic electroreduction of PSSP.     

Nickel‐Catalyzed 1,1‐Alkylboration of Electronically Unbiased Terminal Alkenes

An unprecedented nickel‐catalyzed 1,1‐alkylboration of electronically unbiased alkenes has been developed, providing straightforward access to secondary aliphatic boronic esters from readily available materials under very mild reaction conditions. The regioselectivity of this reaction is governed by a unique pyridyl carboxamide ligated catalyst, rather than the substrates. Moreover, this transformation shows excellent chemo‐ and regio‐selectivity and remarkably good functional‐group tolerance. We also demonstrate that under balloon pressure, ethylene can also be utilized as a substrate. Additionally, competence experiments indicate that selective bond formation is favored at the α‐position of boron and preliminary mechanistic studies indicate that the key step in this three‐component reaction involves a 1,2‐nickel migration.     

基于医用纱布负载的二氧化锰纳米颗粒用于亚甲蓝染料的去除

以医用纱布(medical gauze,MG)同时作为模板和还原剂,通过原位氧化还原反应,简便地制备了MG负载的MnO₂纳米颗粒(MnO₂ NPs/MG),并对其形貌、成分进行表征。结果表明,MnO₂ NPs均匀地分散于MG纤维表面。结合MnO₂纳米材料的吸附性能和MG复合材料的操作便捷性,将MnO₂ NPs/MG进一步应用于亚甲蓝染料的去除。结果表明,在中性条件下,通过简单的浸泡搅拌,MnO₂ NPs/MG对亚甲蓝的去除率可达85.09%,并且可以通过增大吸附材料用量与染料初始浓度的比例提高去除率。等温吸附和动力学研究证明,MnO₂ NPs/MG对亚甲蓝的吸附符合Langmuir吸附等温模型和拟二级动力学模型。     

Investigation on the Inclusion Behavior of ApoCopC with Vitamin B6

In neutral phosphate buffer solution of pH 7.0, the interaction between apoCopC and Vitamin B₆ has been investigated in detail by means of fluorescence spectroscopy. According to the change of Vitamin B₆ fluorescence spectra and fluorescence polarization, we can conclude that a novel supramolecular system is generated. ApoCopC can form a 1:5 host-guest inclusion supramolecular complex with Vitamin B₆, and the formation constant has been calculated to be (2.24 ± 0.08) × 10⁴ M^? 1. It suggests the strong inclusion ability of apoCopC to the guest molecules. In addition, the mechanism of the apoCopC protein fluorescence quenching by Vitamin B₆ was also discussed. And based on the Stern-Volmer equation, the apparent quenching constant was estimated to be (2.75 ± 0.05) × 10⁴ M^? 1.     

Bovine serum albumin-imprinted polyacrylamide gel beads prepared via inverse-phase seed suspension polymerization

Synthetic materials capable of specifically recognition proteins are important in bioseparation and biosensors. In this study, bovine serum albumin-imprinted polyacrylamide gel beads were synthesized via inverse-phase seed suspension polymerization, using high-density crosslinked gel beads as core, low-density crosslinked polyacrylamide gel as imprinting shell. The surface of gel bead had a large quantity of well-distributed macropores, which were suited to let the proteins pass in and out. The selectivity test showed that imprinting gel beads exhibited good recognition for template proteins, as compared to the control protein. We consider the formation of multiple hydrogen bonds and complementary shape between the imprinting cavities and the template proteins are the two factors that lead to the imprinting effect. The imprinting beads had quick adsorption rate and possessed improved regeneration property in comparison with those prepared directly via inverse-phase suspension polymerization.     

陕西煎茶岭矿床的稀土元素地球化学行为

研究表明煎茶岭矿床矿石的稀土组成明显不同于岩石。而镍和金矿床和稀土组成十分相似,富 轻稀土及明显的铕、铈、负异常,反映它们是从同一液中沉淀 。而铈和铕负异常程度差异表明镍矿形成于高温和相对还原的环境,金矿形成在低温和相对化的环境。矿化热液来源于酸性岩浆所分异的热液,成矿元素主要来自超基性岩。     

Phosphorus fractions and phosphate sorption characteristics in relation to the sediment compositions of shallow lakes in the middle and lower reaches of Yangtze River region, China

Phosphorus is recognized as the most critical nutrient limiting lake productivity. The trophic status and development of lake systems are also influenced by the phosphorus content and fractions and phosphate sorption characteristics of the lake sediments. The phosphorus fractions and phosphate sorption characteristics of sediments in shallow lakes from the middle and lower reaches of Yangtze River region in China were investigated. The results show that the phosphorus contents in the sediments ranged from 217.8 to 1640 mg kg(-1); inorganic phosphorus (IP) was the major fraction of total phosphorus (TP); phosphorus bound to Al, Fe, Mn oxides, and hydroxides (Fe/Al-P), and calcium bound phosphorus (Ca-P) were the main fractions of IP. Phosphate sorption on the sediments mainly occurred within 2 h and then reached equilibrium in 10 h. The phosphate sorption rate was closely related to the concentration of fine particles. The phosphate sorption capacity ranged from 128.21 to 833.33 mg kg(-1), showing a significant correlation with the contents of Fe, Fe+Al, total organic carbon (TOC), cationic exchange capacity, total nitrogen, TP, Ca, IP, and the ratio of P/(Al+Fe), and it was higher in the sediments of eutrophic lakes than in mesotrophic lakes. Phosphate was mainly sorbed onto Fe and Al particles. The phosphate sorption efficiency ranged from 26.74 to 312.50 L kg(-1), and had a strong positive correlation with Fe content. For the eutrophic lake sediments, there were no significant relationships between the phosphate sorption efficiency and the selected physical and chemical parameters. But for the mesotrophic lake sediments, the phosphate sorption efficiency was found to be positively related to the contents of Al and Fe+Al.     

具有T型基块的新型金属-有机配位聚合物Mn3(BTC)2(H2O)9·(H2O)的合成与结构

近年来,金属-有机配位聚合物作为一种新型的微孔晶体材料越来越引起人们的广泛关注．这种材料不仅在结构上有类似分子筛的孔道结构,而且在去除孔道中的溶剂分子后仍能保持骨架的完整性,BET比表面积远大于相似孔道的分子筛,所以它们在吸附、分离、催化和分子识别方面具有潜在的价值．不同于由硅氧或铝氧四面体为骨架的传统分子筛微孔材料,这类晶体材料主要是由金属离子（或金属氧簇）与有机配体（大多数是芳香多酸和多碱）构成的建筑单元通过共价键或者分子间作用力构成的．     

丁二烯在稀土催化剂下聚合的链转移

丁二烯在稀土络合催化剂下聚合存在着链转移反应。详细地考察了丁二烯在不同温度下在NdCl₃·3i-PrOH-AlEt₃催化体系下聚合时,各种因素对链转移反应的影响。