树状大分子封装金属纳米粒子的催化作用

树状大分子封装金属纳米粒子是一种新型的有机 /无机杂化纳米材料 ,由树状大分子内螯合金属离子通过还原产生相应的零价金属纳米粒子的方法制备。综述了树状大分子封装金属纳米粒子的催化作用及研究进展 ,讨论了在水、有机溶剂、氟 /有机两相溶剂和超临界CO2 中 ,树状大分子封装催化剂 (DECs)对氢化反应和碳 碳偶合反应的催化作用。最后对树状大分子封装金属纳米粒子的应用进行了展望。     

EXTRACTION OF METAL IONS WITH DZEHPA FROM MIXED AQUEOUS-ORGANIC MEDIA

Extraction of metal ions from the aqueous-organic solution containing dimethyl formamide(DMF), dimethyl sulfoxide(DMSO) and acetonitrile(AN) was investigated by using di-2-ethylhexyl-phosphoric acid(D2EHPA) as an extractant. The organic phase was a binary solution of D2EHPA and n-hexane, or D2EHPA and toluene, while the polar phase was a three component solution of metal salt, non-aqueous solvent and water. The extracted metal ions were Cr(III), Fe(III), Al, Cu, Ni, Co(II), Mg and Ag.

The extraction behaviors may be explained by the solvation ability of non-aqueous solvents, the decrease in distribution of the extractant and extract into the organic phase, and the interaction between the extractant and non-aqueous solvents due to the dissolution of non-aqueous solvents in the organic phase.     

Ionic Liquids as Extraction Solvents: Where do We Stand?

Abstract

The unique physicochemical properties of ionic liquids (ILs) and the relative ease with which these properties can be fine‐tuned by altering the cationic or anionic moieties comprising the IL have led to intense interest in their use as alternatives to conventional organic solvents in a wide range of synthetic, catalytic, and electrochemical applications. Recent work by a number of investigators has been directed at the application of ionic liquids in various separation processes, among them the liquid‐liquid extraction of metal ions. Although certain IL‐extractant combinations have been shown to yield metal ion extraction efficiencies far greater than those obtained with molecular organic solvents, other work suggests that the utility of ILs may be limited by solubilization losses and difficulty in recovering extracted metal ions. In this report, recent efforts to overcome these limitations are described, and progress both in achieving an improved understanding of the fundamental aspects of metal ion transfer into ILs and in devising viable IL‐based systems for metal ion separation is detailed. In addition, areas upon which future research efforts might profitably be focused are identified.     

铟、镓、铊金属离子通过色谱纤维支撑固态膜的传递行为(英文)

The transport of metal ions of indium, gallium and thallium from source solution to receiving phase through the chromatographic fiber supported solid membrane in the acetylacetone (HAA) containing mixed solvent system has been explored. The fibers supported solid membranes were prepared with chemical synthesis from cellulose fibers and citric acid with the carboxylic acid ion exchange groups introduced. The experimental variables, such as concentration of metal ions (10-2 to 10-4 mol·L-1) in the source solu...     

A New Na+‐Dependent RNA‐Cleaving DNAzyme with over 1000‐fold Rate Acceleration by Ethanol

Enzymes working in organic solvents are important for analytical chemistry, catalysis, and mechanistic studies. Although a few protein enzymes are highly active in organic solvents, little is known regarding nucleic acid‐based enzymes. Herein, we report the first RNA‐cleaving DNAzyme, named EtNa, that works optimally in concentrated organic solvents containing only monovalent Na⁺. The EtNa DNAzyme has a rate of 2.0 h^?1 in 54 % ethanol (with 120 mm NaCl and no divalent metal ions), and a K_d of 21 mm Na⁺. It retains activity even in 72 % ethanol as well as in DMSO. With 4 mm Na⁺, the rate in 54 % ethanol is >1000‐fold higher than that in water. We also demonstrated the use of EtNa to measuring the ethanol content in alcoholic drinks. In total, this DNAzyme has three unique features: divalent metal independent activity, Na⁺ selectivity among monovalent metals, and acceleration by organic solvents.     

A bipyridine-containing water-soluble conjugated polymer: Highly efficient fluorescence chemosensor for convenient transition metal ion detection in aqueous solution

A novel sulfonato-functionalized water-soluble conjugated polymer (WSCP), which containing 2′2-bipyridine units as receptors for transition metal ions in the main chain was successfully synthesized by Sonogashira-coupling reaction for the first time. This polymer could easily dissolve in water (5 mg/mL) and some polar organic solvents such as methanol. Its fluorescence in aqueous solution can be completely quenched upon addition of transition metal ions. The K_sv of different transition metal ions in aqueous solution were much higher than previous reports in organic solutions and showed highest selectivity to Ni²⁺. These results opened opportunities for developing novel chemosensors by introducing selective fluorescent chromophore into the water-soluble conjugated backbone.     

巯基化Zr-MOFs/聚酯无纺布复合材料制备及应用

重金属和有机溶剂是水体中常见的污染物,十分有必要开发能够吸附重金属并同时分离有机溶剂的多功能复合材料。本论文以聚酯无纺布（NWF）为基底,经聚二甲基硅氧烷（PDMS）表面改性,进而采用原位生长方式将巯基化锆基金属有机骨架化合物（Zr-MOFs,简称PCN-222）负载在无纺布表面,制备了一种疏水的PDMS/PCN-222@NWF复合材料。在低表面能PDMS改性和原位生长PCN-222晶体所形成的粗糙表面共同作用下,其水接触角为141.7°。油水分离测试结果显示其分离效率最高可达98.6%,并且经过5次循环使用后,分离效率仍然可达94%以上。此外,由于无纺布表面负载有巯基化PCN-222颗粒,PDMS/PCN-222@NWF复合物可同时吸附水中的Hg²⁺,最高吸附量达294.4mg/g。     

离子液体萃取重金属离子的研究进展

离子液体作为一种新型的绿色溶剂,在重金属离子萃取分离方面较传统的有机溶剂有显著的优势。本文系统综述了近年来使用离子液体萃取重金属离子的研究进展,详细讨论了离子液体萃取重金属离子的原理和影响因素,包括螯合剂浓度、萃取时间、萃取温度、离子液体组成、溶液pH值、金属离子初始浓度、干扰离子以及水/离子液体质量比等。进一步介绍了提高离子液体萃取性能的措施以及金属离子的脱除与离子液体的回收状况,以及该萃取方法在废水处理、重金属离子分析和冶金中的研究与应用现状,最后指出其未来发展方向是合成功能化离子液体、提高萃取效率,以实现其工业化应用。     

Ultrasensitive DNAzyme‐Based Ca2+ Detection Boosted by Ethanol and a Solvent‐Compatible Scaffold for Aptazyme Design

Functional DNA includes aptamers and DNAzymes, and metal ions are often important for achieving the chemical functions of such DNA. Biosensors based on functional DNA have mainly been tested in aqueous buffers. By introducing organic solvents with much lower dielectric constants, the interaction between metal ions and DNA can be significantly enhanced, and this might affect the performance of DNA‐based biosensors. In this work, the effect of ethanol on the activity of the EtNa DNAzyme was studied for Ca²⁺ detection. With 30 % ethanol, the sensor has a detection limit of 1.4 μm Ca²⁺, which is a 16‐fold improvement relative to that in water. This EtNa DNAzyme is unique because other tested DNAzymes are all inhibited by 50 % ethanol. Finally, by using the EtNa DNAzyme as a scaffold, the adenosine monophosphate (AMP) aptamer was inserted to construct an aptazyme, which allowed the measurement of AMP in ethanol. In summary, this study has reported the most sensitive DNA‐based sensor for Ca²⁺, and its sensitivity and selectivity can approach those of proteins or small‐molecule ligands. This work also provides a way to measure aptamer binding in organic solvents.     

Use of ionic liquids as ‘green’ solvents for extractions

This review summarizes recent applications of ionic liquids (ILs) as ‘green’ solvents in extractions of a variety of substances, including metal ions, organic and bio‐molecules, organosulfur from fuels, and gases. ILs could also be used along with another ‘green’ technology, supercritical fluid extraction (SFE), for a more effective separation of products from ILs. In addition to their environmentally‐benign feature, ILs have other favorable properties over organic solvents used for extraction, such as adjustable hydrophobicity, polarity and selectivity. Copyright © 2005 Society of Chemical Industry     

ion-Exchange Paper Chromatography of Metal Ions with Mixed Aqueous-Organic Solvents Containing Mineral Acid and a Selective Extractant

Abstract

Mixed solvents containing an organic extractant provide selective separations of metal ions on cation- and anion-exchange papers. The separations of scandium, hafnium plus zirconium, nickel, and thorium from complex mixtures are demonstrated. Various separations in dithizone and dimethyl-sulfoxide media are also reported. Results are often the same as those achieved on columns of resin with the same mobile phase.     

Application of ionic liquids as mobile phase additives and surface-bonded stationary phase in liquid chromatography

Ionic liquids (ILs) have gained wide recognition as novel solvents in chemistry. Their application in analytical chemistry, especially in separating analytes, is warranted due to their unique properties such as negligible vapor pressure, good thermal stability, tunable viscosity and miscibility with water and organic solvents, as well as good extractability for various organic compounds and metal ions. Recently, some new chromatographic separation media, formed by combining ILs on silica and polymer surface using covalently or non-covalently interaction, have been developed and applied to biological separation and environment analysis. This review will focus on some of the properties of ILs and their potential application as mobile phase modifier and surface-bonded stationary phase in high-performance liquid chromatography (HPLC) separation.     

New phenylated polyphenylenes carrying main-chain bipyridyl groups and their complexes with metal ions

New phenylated polyphenylenes containing main-chain bipyridyl groups are prepared by the interaction of 5,5′-diethynyl-2,2′-bipyridyl with various bis(cyclopentadienones) via the Diels-Alder reaction. The polymers exhibit fluorescence, can chelate metal ions, and combine solubility in organic solvents with high viscosity and thermal characteristics. The parameters of fluorescence and the efficiency and selectivity of complexation of bipyridyl-containing polyphenylenes depend on their structure and nature of metals.     

环境因素和培养条件对类胡萝卜素表达的影响

阐述了环境和培养条件的改变对于不同的微生物提高类胡萝卜素单位体积产量和单位细胞产量的作用,这些微生物包括微藻、真菌和细菌。可采用的条件有调节光照、改变培养温度、向培养基中添加金属离子、盐类、有机溶剂、前体和其他的化学刺激物等。     

金属有机框架材料的绿色合成

金属有机框架化合物（Metal-organic frameworks,简称MOFs）是由金属离子（或簇）与有机配体配位并经由自组装而形成的一类多孔材料^[1]。MOFs具有极其发达的孔道结构,比表面积和孔容远超其他多孔材料。有机/无机杂化这一特点也赋予了MOFs其他材料（例如沸石、活性炭等）所不具备的无限结构功能可调性^[2]。此外,MOFs具有移除客体分子而主体框架完好保持的持久孔道或孔穴,这使得MOFs具有超乎寻常的化学及物理稳定性。正是基于以上这些特点,MOFs在许多领域有着丰富的应用^[3-4],例如催化^[5]、H₂储存^[6]、CO₂捕集^[7]、药物运输^[8]、污染物吸附^[9]、生物医学成像^[10]等方面。MOFs的商业化探索成为了目前的热点。MOFs的很多应用都与可持续发展及“绿色材料”有关,但MOFs本身的合成过程也需要考虑可持续性和环境影响。金属有机化学所面临的环境挑战是独特的,因为它将金属离子、有机配体的危害联系在一起,且合成过程大多需要大量能耗。主要介绍了金属有机框架材料的绿色可持续合成,主要分为4个方面：1）使用更安全或生物相容性的配体;2）使用更绿色、低成本的金属源;3）绿色溶剂的开发;4）无溶剂合成法。     

EXTRACTION OF HEAVY METAL IONS WITH 3-[(DIOCTYLAMINO)METHYL]ALIZARIN

3-[(Dioctylamino)methyl]alizarin (C₈AL), which is endowed with high solubility in nonpolar organic solvents through introduction of dioctylaminomethyl group into the alizarin nucleus was studied for extracting heavy metal ions such as Cu(II), Zn(II), Cd(II), Co(II), Mn(II), and Ni(II), from aqueous solution.Cu(II) was most readily extracted into chlorobenzene at low pH and thus was separated from other metal ions. The metal ions stabilized in alkaline solution in the presence of water-soluble chelating agents were found to be extracted by this, alizarin-type extraction agent into chlorobenzene with the assistance by lipophilic quaternary ammonium salt, Capriquat? (methyltrioctylammonium chloride, Q^?C1^?).The proton dissociation process of CRAL was studied, and the mechanism of these metal extractions was discussed.The separation of Cu(II) and Ni(II) from the mixture with other divalent metal ions was also studied.     

The Synthesis and Characterization of New Schiff Bases and Investigating them in Solvent Extraction of Chromium and Copper

New Schiff bases containing nitrogen, sulfur and oxygen donor atoms, were designed and synthesized in a multi—step reaction sequence. The Schiff base(I) was used in solvent extraction of metal chlorides such as Cu(II) from aqueous phase to the organic phase. The influences of the parameter functions, such as pH, solvent, ionic strength of aqueous phase, aqueous to organic phase, and concentration of the extractant were investigated to shed light on their chemical extracting properties upon the extractability of metal ions. The effect of chloroform, dichloromethane, and nitrobenzene as organic solvents over the metal chlorides extraction was investigated at 25 ± 0.1°C by using flame atomic absorption and the result is that the ability of extraction in solvents as follows C₆H₅NO₂ > CHCl₃ > CH₂Cl₂.     

离子液体在萃取分离中的应用

室温离子液体是由正负离子组成的室温为液体的熔融盐,因其具有极低的蒸汽压、可设计性和特殊的选择溶解能力等独特的性质,使得其在萃取分离有机物及金属离子、液相微萃取和汽油柴油中脱硫及碱性氮化物等领域都有着广泛应用。综述了离子液体在萃取分离上的应用进展。     

Design and Synthesis of Chiral Zn2+ Complexes Mimicking Natural Aldolases for Catalytic C–C Bond Forming Reactions in Aqueous Solution

Extending carbon frameworks via a series of C–C bond forming reactions is essential for the synthesis of natural products, pharmaceutically active compounds, active agrochemical ingredients, and a variety of functional materials. The application of stereoselective C–C bond forming reactions to the one-pot synthesis of biorelevant compounds is now emerging as a challenging and powerful strategy for improving the efficiency of a chemical reaction, in which some of the reactants are subjected to successive chemical reactions in just one reactor. However, organic reactions are generally conducted in organic solvents, as many organic molecules, reagents, and intermediates are not stable or soluble in water. In contrast, enzymatic reactions in living systems proceed in aqueous solvents, as most of enzymes generally function only within a narrow range of temperature and pH and are not so stable in less polar organic environments, which makes it difficult to conduct chemoenzymatic reactions in organic solvents. In this review, we describe the design and synthesis of chiral metal complexes with Zn²⁺ ions as a catalytic factor that mimic aldolases in stereoselective C–C bond forming reactions, especially for enantioselective aldol reactions. Their application to chemoenzymatic reactions in aqueous solution is also presented.     

Polychelates of poly[N-(4-carboxy-3-hydroxyphenyl)maleimide]

The reactions of the bidentate polymeric chelating ligand poly[N-(4-carboxy-3-hydroxyphenyl)maleimide] with Co(II), Ni(II), Cu(II), Zn(II) and UO₂(II) metal ions were investigated. Analytical, magnetic, spectral and thermal studies were used to characterize these polychelates. All these polychelates are stable, intensely coloured solids and insoluble in common organic solvents.