A mixed‐valence chloride‐bridged (pincer)IrIII–(diene)IrI complex

The title compound, [2,6‐bis(di‐tert‐butylphosphino)phenyl‐1κ³P,C¹,P′]di‐μ‐chlorido‐1:2κ⁴Cl:Cl‐(2η⁴‐cycloocta‐2,5‐diene)hydrido‐1κH‐diiridium(I,III) hexane hemisolvate, [Ir₂(C₈H₁₂)(C₂₄H₄₃P₂)Cl₂H]·0.5C₆H₁₄ or [(^tBuPCP)IrH(μ₂‐Cl)₂Ir(COD)][^tBuPCP is κ³‐2,6‐(^tBu₂PCH₂)₂C₆H₃ and COD is η⁴‐2,5‐cyclooctadiene], is an Ir^III/Ir^I dimer bridged by two chloride ions. The Ir₂Cl₂ framework is nearly planar, with a dihedral angle of 13.04 (4)° between the two Ir centers. The compound was isolated as a hexane hemisolvate. A list of distances found in Ir(PCP) compounds is given.     

Oxydative Umwandlung von 17-Alkoxy-aspidospermidin-Derivaten in 17, 17-Dialkoxy-17, 18-dihydro-1, 18-dehydro-aspidospermidine

Treatment of 17-alkoxy-aspidospermidine derivatives with iodine and sodium hydroxide in methanolic or ethanolic solution yields the corresponding 17, 17-dialkoxy-17, 18-dihydro-1, 18-dehydro-aspidospermidine. Hence compounds 1 and 2 in methanol give the oxidation products 8 and 3 , respectively. In ethanol, 4 is converted to 5 , 2 to a mixture of 6 and 7 ; 4 in methanol yields a mixture of 6 and 7 in a different ratio.     

Thermochemistry on the Complex of Erbium Perchlorate with L-α-Glutamic Acid [Er2（L-Glu）2（H2O）6]（ClO4）4·6H2O（s）

A coordination compound of erbium perchlorate with L-α-glutamic acid, [Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）, was synthesized. By chemical analysis, elemental analysis, FTIR, TG/DTG, and comparison with relevant literatures, its chemical composition and structure were established. The mechanism of thermal decomposition of the complex was deduced on the basis of the TG/DTG analysis. Low-temperature heat capacities were measured by a precision automated adiabatic calorimeter from 78 to 318 K. An endothermic peak in the heat capacity curve was observed over the temperature region of 290-318 K, which was ascribed to a solid-to-solid phase transition. The temperature Ttrans, the enthalpy △transHm and the entropy △transSm of the phase transition for the compound were determined to be： （308.73±0.45） K, （10.49±0.05） kJ·mol^-1 and （33.9±0.2） J·K^-1·mol^-1. Polynomial equation of heat capacities as a function of the temperature in the region of 78-290 K was fitted by the least square method. Standard molar enthalpies of dissolution of the mixture [2ErCl3·6H2O（s）＋2L-Glu（s）＋6NaClO4·H2O（s）] and the mixture {[Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）＋6NaCl（s）} in 100 mL of 2 mol·dm^-3 HClO4 as calorimetric solvent, and {2HClO4（1）} in the solution A＇ at T=298.15 K were measured to be, △dHm,1=（31.552±0.026） kJ·mol^-1, △dHm,2 = （41.302±0.034） kJ·mol^-1, and △dHm,3 = （ 14.986 ± 0.064） kJ·mol^-1, respectively. In accordance with Hess law, the standard molar enthalpy of formation of the complex was determined as △fHm-=-（7551.0±2.4） kJ·mol^-1 by using an isoperibol solution-reaction calorimeter and designing a thermochemical cycle.     

Estimates of the uniform modulus of continuity for Bessel potentials

In the theory of function spaces it is an important problem to describe the differential properties for the classical Bessel and Riesz potentials as well as for their generalizations. Bessel potentials are determined by the convolutions of functions with Bessel-MacDonald kernels G _α. In this paper we characterize the integral properties of functions by their decreasing rearrangements. The differential properties of potentials are characterized by their modulus of continuity of order k in the uniform norm. Estimates of such type were obtained by A. Gogatishvili, J. Neves, and B. Opic in the case k > α. Here, we remove this restriction and obtain the results for all values k ∈ N. We find order-sharp estimates from above for moduli of continuity and construct the examples confirming the sharpness. On the base of these results we obtain the order-sharp estimates for continuity envelope function in the space of potentials, and give estimates for the approximation numbers of the embedding operator.     

Covalent Organic Frameworks(COFs) for Sequestration of99TcO4–

Covalent organic frameworks(COFs), as a class of crystalline porous materials with periodic lattices and porous structures, have received extensive attention in the fields of gas storage and separation, energy storage, catalysis and optoelectronics and so on. However, COFs are still in their infancy in the field of nuclear waste treatment, especially for sequestration of long-live problematic radionuclides, such as ⁹⁹Tc. Battle of decontamination of pertechnetate(TcO₄^–), a main existence of ⁹⁹Tc under aerobic environments, is far from finished. In this review, recent progresses of COFs and some relative materials in the sequestration of pertechnetate, and perspective on surmounting the unmet issues are elucidated.     

中药炮制机理研究的思路与方法——以咖啡豆的烘焙原理研究为例

中药炮制是中药学的特色和优势,也是最具我国自主知识产权的学科之一.中药炮制研究的核心是阐明中药炮制机理,这也是制约中药现代化的关键节点.目前大部分中药的炮制机理尚不明确,有待进行系统深入的研究.咖啡豆需要烘培后才可以制成饮料,这个高温烘培过程类似于中药的炮制过程.近年来,国内外专家对咖啡豆高温烘培过程化学成分变化及其机理进行了深入研究,各种新方法和新技术得到广泛应用,取得了系列研究成果,这些研究成果为中药炮制机理研究提供了多种新思路和新方法,也为中药炮制机理的研究和阐明提供了重要示范.     

Comparison of an antibody and its recombinant derivative for the detection of the small molecule explosive 2,4,6-trinitrotoluene

Antibodies are commonly used as recognition elements in immunoassays because of their high specificity and affinity, and have seen extensive use in competitive assays for the detection of small molecules. However, these complex molecules require production either in animals or by mammalian cell cultures, and are not easily tailored through genetic manipulation. Single chain antibodies (scFv), recombinantly expressed molecules consisting of only the antibody's binding region joined via a linking peptide, can provide an alternative to intact antibodies. We describe the characterization of a new monoclonal antibody (mAb), 2G5B5, able to detect the small molecule explosive 2,4,6-trinitrotoluene (TNT) and the scFv derived from its variable regions. The mAb and scFv were tested by surface plasmon resonance to determine their affinity for an immobilized TNT surrogate; dissociation constants were determined to be 1.5 × 10⁻¹³ M and 4.8 × 10⁻¹⁰ M respectively. Circular dichroism was used to determine their melting temperatures. The mAb is more stable melting at ∼75 °C while the scFv melts at ∼65 °C. The recognition elements were incorporated into a competitive assay format using a bead-based multiplexing platform to examine their sensitivity and specificity. The scFv was able to detect TNT ∼10-fold more sensitively than the mAb in this assay format, allowing detection of TNT concentrations down to at least 1 μg L⁻¹. The 2G5B gave similar detection limits to a commercial anti-TNT mAb, but was less specific, recognizing 1,3,5-trinitrobenzene (TNB) equally well as TNT.     

分光光度法测定核桃青皮中总黄酮方法的修正

应用亚硝酸钠-硝酸铝-氢氧化钠体系分光光度法测定核桃花青皮中总黄酮含量时受到共存的胡桃醌和焦性没食子酸的明显干扰,经试验,提出了消除此干扰的校正方法。从乙醇提取液中移取两份等量试液(2.0mL),分别置于25mL容量瓶中,其中一份按方法加显色混合液,以试剂空白为参比,在波长508nm处先后于15,25min测其吸光度A1及A2;另一份中加乙醇(1+1)溶液13mL及40g·L-1氢氧化钠溶液10.0mL,摇匀,测其吸光度A0。根据所推导的公式计算总黄酮的吸光度,代入回归方程计算其含量。按改进的方法分析3份样品,测定值的相对标准偏差(n=6)在0.76%～1.3%之间。加标回收试验的回收率在89.0%～105%之间。     

晶化时间对ZSM-5/MCM-48复合分子筛结构及MTG反应性能的影响

采用两步晶化法制备ZSM-5/MCM-48微介孔复合分子筛,通过调变前驱体溶胶的晶化时间获得不同结构的ZSM-5/MCM-48基分子筛催化剂。采用XRD、N₂-吸附、SEM、TEM、FT-IR和Py-FTIR等手段进行表征,结果表明,前驱体溶胶的晶化时间对ZSM-5/MCM-48复合分子筛的结构和表面酸性产生重要的影响,而特定结构的复合分子筛基催化剂可以显著改变甲醇制汽油（MTG）反应的产物分布,与ZSM-5基催化剂相比显著降低了油品中芳烃和均四甲苯的含量。阐明了其催化作用机制是由于介孔结构的MCM-48对微孔结构的ZSM-5界面或表面的修饰作用。