Ascorbate-induced oxidation of formate by peroxodisulfate: product yields,kinetics and mechanism

The slow reaction between peroxodisulfate and formate is significantly accelerated by ascorbate at room temperature. The products of this induced oxidation, CO₂ and oxalate (C₂O^2– ₄), were analyzed by several methods and the kinetics of this reaction were measured. The overall mechanism involves free radical species. Ascorbate reacts with peroxodisulfate to initiate production of the sulfate radical ion (SO^– ₄), which reacts with formate to produce carbon dioxide radical ion (CO^– ₂) and sulfate. The carbon dioxide radical reacts with peroxodisulfate to form CO₂ or self-combines to form oxalate. Competition occurring between these two processes determines the overall fate of the carbon dioxide radical species. As pH decreases, protonation of the carbon dioxide radical ion tends to favor production of CO₂.     

Secondary Metabolites from the Fruiting Bodies of Coriolopsis aspera in Vietnam and their Bioactivities

Chemistry of Natural Compounds -     

大白鼠的肝电探测及肝电效应

介绍了一种探测大白鼠肝肝电的方法和几种肝电图，并探讨了鼠肝肝电产生的机理；还发现鼠肝具有二极管效应和储电能力．根据鼠肝肝电图和上述肝电效应能明确区分肝功能正常鼠和肝功能异常鼠（包括患肝病鼠）．     

Novel class of heterometallic cubane and boride clusters containing heavier group 16 elements

Thermolysis of an in situ generated intermediate, produced from the reaction of [Cp*MoCl(4)] (Cp* = η(5)-C(5)Me(5)) and [LiBH(4).THF], with excess Te powder yielded isomeric [(Cp*Mo)(2)B(4)TeH(5)Cl] (2 and 3), [(Cp*Mo)(2)B(4)(μ(3)-OEt)TeH(3)Cl] (4), and [(Cp*Mo)(4)B(4)H(4)(μ(4)-BH)(3)] (5). Cluster 4 is a notable example of a dimolybdaoxatelluraborane cluster where both oxygen and tellurium are contiguously bound to molybdenum and boron. Cluster 5 represents an unprecedented metal-rich metallaborane cluster with a cubane core. The dimolybdaheteroborane 2 was found to be very reactive toward metal carbonyl compounds, and as a result, mild pyrolysis of 2 with [Fe(2)(CO)(9)] yielded distorted cubane cluster [(Cp*Mo)(2)(BH)(4)(μ(3)-Te){Fe(CO)(3)}] (6) and with [Co(2)(CO)(8)] produced the bicapped pentagonal bipyramid [(Cp*MoCo)(2)B(3)H(2)(μ(3)-Te)(μ-CO){Co(3)(CO)(6)}] (7) and pentacapped trigonal prism [(Cp*MoCo)(2)B(3)H(2)(μ(3)-Te)(μ-CO)(4){Co(6)(CO)(8)}] (8). The geometry of 8 is an example of a heterometallic boride cluster in which five Co and one Mo atom define a trigonal prismatic framework. The resultant trigonal prism core is in turn capped by two boron, one Te, and one Co atom. In the pentacapped trigonal prism unit of 8, one of the boron atoms is completely encapsulated and bonded to one molybdenum, one boron, and five cobalt atoms. All the new compounds have been characterized in solution by IR, (1)H, (11)B, and (13)C NMR spectroscopy, and the structural types were unambiguously established by crystallographic analysis of 2 and 4-8.     

Ultrafast Dynamics of Solvation and Charge Transfer in a DNA‐Based Biomaterial

Charge migration along DNA molecules is a key factor for DNA‐based devices in optoelectronics and biotechnology. The association of a significant amount of water molecules in DNA‐based materials for the intactness of the DNA structure and their dynamic role in the charge‐transfer (CT) dynamics is less documented in contemporary literature. In the present study, we have used a genomic DNA–cetyltrimethyl ammonium chloride (CTMA) complex, a technological important biomaterial, and Hoechest 33258 (H258), a well‐known DNA minor groove binder, as fluorogenic probe for the dynamic solvation studies. The CT dynamics of CdSe/ZnS quantum dots (QDs; 5.2 nm) embedded in the as‐prepared and swollen biomaterial have also been studied and correlated with that of the timescale of solvation. We have extended our studies on the temperature‐dependent CT dynamics of QDs in a nanoenvironment of an anionic, sodium bis(2‐ethylhexyl)sulfosuccinate reverse micelle (AOT RMs), whereby the number of water molecules and their dynamics can be tuned in a controlled manner. A direct correlation of the dynamics of solvation and that of the CT in the nanoenvironments clearly suggests that the hydration barrier within the Arrhenius framework essentially dictates the charge‐transfer dynamics.     

一类R~n上半线性椭圆方程有界正解的存在性和对称性

本文研究 Rn上型如下列具有次线性项加超线性项椭圆方程 :-Δu =a(x) (λus up) ,x∈ Rn,其中 ,n≥ 3,0 0为参数 .用上下解方法给出了方程有界正解存在性及多解性结果 .用移动平面方法给出解的径向对象性结果 .     

Chemical Profiles and Antibacterial Activity of Essential Oils from Rhizomes of Aspidistra phanluongii

Chemistry of Natural Compounds -     

Chiral Organocatalysts in Enantioselective CO2 Utilization Reactions

The development of efficient CO₂ utilization reactions has gained a significant amount of attention in recent years. Although transformations of CO₂ to produce basic chemicals have been extensively investigated, the development of catalytic enantioselective CO₂ utilization reactions for the preparation of fine chemicals remains limited at this stage. Several excellent methods for catalytic enantioselective CO₂ utilization using chiral metal complex catalysts have been reported. Many researchers have also focused on developing organocatalyzed approaches to enantioselective CO₂ utilization, and several excellent examples have appeared in recent years. Herein, recent advances in catalytic enantioselective CO₂ utilization reactions using chiral organocatalysts are reviewed to provide a forecast for organocatalyzed enantioselective CO₂ utilization research.     

襄樊市区1235名孕妇尿碘含量监测分析

对襄樊市区孕妇尿碘含量进行了监测。监测结果：尿碘低于１００μｇ／Ｌ者，３０岁以上年龄组为高，达４８．３９％，９－１１月季节组为高，达４４．３５％；７个月以上的孕期组为高，达３０．６４％，农民缺磺情况远远高于工人（２６．０７％）、干部（２２．３％）、商人（１５．９８％），其尿碘平均含量低于１００μｇ／Ｌ者，高达４０．４５％，为各职业之冠，可见孕妇尿碘含量监测的重点应是病区农民。