Das Organosol des Goldes

Ohne Zusammenfassung(Mitteilung aus der Königl. Untersuchungsanstalt für Nahrungs- und Genußmittel zu Erlangen.)     

The Effects of Methylene Blue on the Optical Properties of Nanometer-sized CdS Organosol

The inverse micelle system of nanometer-sized CdS doped with Methylene Blue(MB) was synthesized and characterized by using absorption and fluorescence spectra. The results show that MB molecules were absorbed onto the surface of CdS nanoparticles and interacted with surfactants when its concentration was lower than 4×10^-6 mol/L. From the comparison of their spectra, MB molecules by adsorption have a strong quenched fluorescence emission of CdS nanoparticles with surface defect states. All responses and main mechanism are ascribed to the charge transfer between the CdS organosol and Methylene Blue molecules.     

A New Method of Preparing Copper Oxide from Dinitrourea Copper Salt

A new approach for the preparation of copper nanooxide by solvothermal decomposition of N, N′‐dinitrourea copper(II) salt in an aprotic solvent was developed. The resulting particles were studied by transmission electron microscopy, X‐ray photoelectron spectroscopy, and small‐angle X‐ray scattering. The effects of different solvents on shapes of the agglomerates formed are shown.     

A Bead Injection System for Copper Determination

ABSTRACT

A bead injection system for copper determination is proposed. Chelex-100 resin beads are introduced in the system as a suspension that is trapped in the Jet Ring Cell. The passage of the sample zone by the beads promotes the sorption of Cu(II). When the colorimetric reagent (APDC) perfuses the beads it reacts with copper ions, forming a colored complex that is monitored at 436 nm. After the measurement, the spent beads are sent to waste and a new portion of fresh beads is trapped in the system. The bead injection system is versatile and can be used to concentrate analyte in different sample volumes, permitting determinations of a wide range of copper concentrations. The detection limit is 0.5 μg l^-1 with a 500 μl sample, and 1.2 μg l^-1 with a 100 μ1 sample.     

A Valence Tautomeric Dinuclear Copper Tetrakisguanidine Complex

We report on the first valence tautomeric dinuclear copper complex, featuring 2,3,5,6‐tetrakis(tetramethylguanidino)pyridine as a bridging redox‐active GFA (guanidino‐functionalized aromatic) ligand. The preferred electronic structure of the complex is massively influenced by the environment. In the solid state and in nonpolar solvents a paramagnetic, dinuclear Cu^II complex with a neutral GFA ligand is present. In polar solvents, the electronic structure changes to a diamagnetic, dinuclear Cu^I complex with a twofold‐oxidized GFA ligand. Using acetone as a solvent, both electronic structures are accessible due to a temperature‐dependent equilibrium between the two valence tautomeric complexes. Our results pave the way for a broader use of valence tautomeric transition‐metal complexes in catalytic reactions since anionic coligands can now be tolerated owing to the neutral/positively charged GFA ligand.     

A Fluxional Copper Acetylide Cluster in CuAAC Catalysis

A molecularly defined copper acetylide cluster with ancillary N‐heterocyclic carbene (NHC) ligands was prepared under acidic reaction conditions. This cluster is the first molecular copper acetylide complex that features high activity in copper‐catalyzed azide–alkyne cycloadditions (CuAAC) with added acetic acid even at ?5 °C. Ethyl propiolate protonates the acetate ligands of the dinuclear precursor complex to release acetic acid and replaces one out of four ancillary ligands. Two copper(I) ions are thereby liberated to form the core of a yellow dicationic C₂‐symmetric hexa‐NHC octacopper hexaacetylide cluster. Coalescence phenomena in low‐temperature NMR experiments reveal fluxionality that leads to the facile interconversion of all of the NHC and acetylide positions. Kinetic investigations provide insight into the influence of copper acetylide coordination modes and the acetic acid on catalytic activity. The interdependence of “click” activity and copper acetylide aggregation beyond dinuclear intermediates adds a new dimension of complexity to our mechanistic understanding of the CuAAC reaction.     

新型铜粉导电复合物的合成

以Bi_2O_3与Sn(OH)_4为原料、NaBH_4为还原剂,成功在3.5μm球形铜粉表面包覆了Sn-Bi合金层,将铜粉与高分子基体(聚乙烯吡咯烷酮、丙烯酸树脂、环氧树脂)复合制备了导电复合物。采用场发射扫描电镜(SEM)、能谱仪(EDS)与差示扫描量热仪(DSC)表征包覆铜粉的组成与结构,采用刮板细度计测试复合物的分散与稳定性能,并用万用电表测试其导电性能。结果表明,包覆铜粉复合物的导电性能较纯铜粉复合物明显提高。     

A Luminescent One-Dimensional Copper(I) Polymer

The synthesis and structure of a one-dimensional polymer of formula [Cu₃(dpphp)₂(MeCN)_1.7(CH₂Cl₂)_0.3](ClO₄) _n is reported (where dpphp=6-diphenylphosphino-2-pyridonate). There are three distinct copper(I) sites within the polymer. Two of these sites are four-coordinate, bound to one P- and two O-atoms and a solvate molecule; the third site is bound only to two N-atoms. The Cu*Cu distances within the polymer are around 2.8 Å. The compound is luminescent in the solid-state.     

新的化学发光体系测定铜

研究了水杨酸 (R)与Cu(Ⅱ )配合物 (CuR2 2 -)催化H2 O2 氧化鲁米诺产生化学发光反应 ,最低检出限为 6 .6×10 -11g/mL ,工作曲线线性范围为 1× 10 -10 ～ 1× 10 -7g/mL ,在检测 0 .1μgCu(Ⅱ )的浓度时的相对标准偏差 (RSD)为2 .7% .铜配合物化学发光法检测病毒灵片剂 (盐酸吗林胍片 )中微量铜时快速地得到准确的结果     

一种快速生成铜锈的实验方法

本实验运用电化学的方法,将简单易得的材料用于快速制备铜锈,在几十秒到几分钟不等的时间就会迅速产生铜锈。依据XRD图谱对产物进行分析,确定了形成碱式氯化铜(Cu₂Cl-(OH)₃)的最佳电解质溶液配比,并成功制备了碱式碳酸铜(Cu₂(CO₃)(OH)₂)。实验结果可用作中学化学教学演示实验和学生实验,也可用于指导学生探究不同条件对铜锈制备的影响,进行探索性学习练习。此外,相关实验原理可提供试题情境对学生学习质量进行评价。     

Determination of Copper in High Purity Copper

Copper ions play a key role in Industry, Agriculture,National Defense and Scientific Research. The flash furnace copper cooling jackets manufactured by our yard require perfect inside quality,content of copper reaches 99.6-99.9 percent. An accurate and rapid method of determining copper content is needed for large bulk production.     

A Simplified Nitroso-R Salt-Based Optic Fiber Sensor for Copper

Copper (II) has been measured using a reflection-based optic fiber sensor associated with flow-injection analysis. The sensing layer consists of Nitroso-R salt immobilized on Amberlyst A-27 resin. The sensor responses linearly in the copper concentration range 0.01-1.0 μg/ml with a detection limit of 5.0 ng/ml. The relative standard deviation of seven measurements of 0.5 μg/ml copper was 6.0%. The sensor was not fully reversible but can be fully regenerated by using 1.0 M hydrochloric acid after each measurement.     

Cu－ZSM－5分子筛表面铜离子的价态研究

以吸附ＣＯ红外光谱结合ＴＰＲ谱详细表征了经真空自还原及用不同还原剂还原的ＣｕＺＳＭ－５分子筛样品，考察了表面铜离子的价态分布情况及其影响因素。得知铜在Ｃｕ－ＺＳＭ－５表面是分步还原的。用不同方法进行氧化和还原时的难易程度不同。研究了用不同方法进行氧化还原时铜的价态转变条件和铜离子在不同价态间氧化还原循环的可逆性。Ｃｕ２＋与Ｃｕ＋间的氧化还原循环完全可逆，而Ｃｕ０与Ｃｕ＋间的氧化还原循环不完全可逆。Ｃｕ０氧化为Ｃｕ＋比Ｃｕ＋氧化为Ｃｕ２＋容易进行，探讨了Ｃｕ＋在Ｃｕ－ＺＳＭ－５分子筛中不同位置的分布情况及铜在不同条件下的氧化还原机理。     

A Copper(I)-Catalyzed Sulfonylative Hiyama Cross-Coupling

An air-tolerant Cu-catalyzed sulfonylative Hiyama cross-coupling reaction enabling the formation of diaryl sulfones is described. Starting from aryl silanes, DABSO and aryliodides, the reaction tolerates a large variety of polar functional groups (amines, ketones, esters, aldehydes). Control experiments coupled with DFT calculations shed light on the mechanism, characterized by the formation of a Cu(I)-sulfinate intermediate via fast insertion of a SO₂ molecule.     

A Surface Coordination Network Based on Copper Adatom Trimers

Surface coordination networks formed by co‐adsorption of metal atoms and organic ligands have interesting properties, for example regarding catalysis and data storage. Surface coordination networks studied to date have typically been based on single metal atom centers. The formation of a novel surface coordination network is now demonstrated that is based on network nodes in the form of clusters consisting of three Cu adatoms. The network forms by deposition of tetrahydroxybenzene (THB) on Cu(111) under UHV conditions. As shown from a combination of scanning tunneling microscopy, X‐ray photoelectron spectroscopy, and density functional theory calculations, all four hydroxy groups of THB dehydrogenate upon thermal activation at 440 K. This highly reactive ligand binds to Cu adatom trimers, which are resolved by high‐resolution STM. The network creates an ordered array of mono‐dispersed metal clusters constituting a two‐dimensional analogue of metal–organic frameworks.     

荧光光度法测定痕量铜的研究

本文撰写了荧光法测定铜的新方法，详细研究了Ｃｕ－硫胺素体系测铜的最佳条件，该法简便、选择性好，灵敏度高，检测限可达０．２５ｎｇ／ｍｌ，用于人发和纯铝样品中铜含量的测定，结果令人满意。