Microchip capillary electrophoresis with amperometric detection for several carbohydrates

Microchip capillary electrophoresis (μCE) with amperometric detection at Cu electrode benefited fast separation and direct detection of carbohydrates. The working electrode of 50-μm Cu wire attached nearly against the channel outlet—4 μm, where it benefited collecting detection current and suppressing overwhelming noise. The use of alkaline medium was essential to separating and detecting carbohydrates, which dissociated into the sensitive alcolate anions. The 10-cm serpentine chip, though lengthening the migration time, it provided better efficiency. Sucrose, cellobiose, glucose, and fructose migrated from the outlet in 400 s +2000 V. The linear calibration plots ranging from 10 to 1000 μM with regression coefficients better than 0.996 were obtained. The injection-to-injection reproducibility of 1.24% (n=7) for glucose in peak current and 0.6% for migration times were excellent. The detection limit was low, down to 2.3 μM for glucose (S/N=3) or 27.6 attomole in mass detection.     

Synthesis,Spectroscopic and EPR Results and Crystal Structure of Copper(II) Formato Derivatives with Pyrazine and Dimethylpyrazines

The complexes of copper formato with pyrazine and dimethylpyrazines: Cu(HCOO)₂(pyrz) ( 1 ), Cu₂(HCOO)₄(pyrz) ( 2 ), Cu₂(HCOO)₄(2,3‐Me₂pyrz) ( 3 ), Cu₂(HCOO)₄(2,5‐Me₂pyrz) ( 4 ), and Cu₂(HCOO)₄(2,6‐Me₂pyrz)₂ ( 5 ) have been synthesized and characterized by chemical analysis and IR and electronic spectro scopies. The three‐dimensional structure of compound 1 consists of –Cu–pyrz–Cu–pyrz– chains joined by bridging formate groups coordinated, in configuration syn‐anti, to two copper atoms. The coordination around the copper atom is orthorhombic with two Cu–O distances of 2.374(1) Å, two Cu–O of 1.952 Å and two Cu–N of 2.080 Å. Compound 5 is formed by molecular dimers with the [Cu₂(μ‐HCOO)₄] unit, two copper atoms and four syn‐syn fomate groups, and two ligands coordinated to the copper atoms in the axial positions. In compounds 2 and 3 chains of [Cu₂(μ‐HCOO)₄] dimers with pyrz or 2,3‐Me₂pyrz as bridging ligands are formed. The EPR signal of 1 is orthorhombic (g = 2.23, 2.20 and 2.06). In the EPR spectra of 2 – 5 compounds the triplet (S = 1) signals are observed. The g_?, g_∥ and D values are been calculated.     

过渡金属大环配合物的研究Ⅲ 4-硝基-苯并15冠-5与钴(Ⅱ)、铜(Ⅱ)和银(Ⅰ)配合物的合成及性质

有关冠醚配体与碱金属,碱土金属和稀土离子形成配合物的特性研究,国内外均有报导,但冠醚与d-过渡金属离子配合物的研究工作,则开展较晚,文献报导亦甚少。本文为探讨4-硝基-苯并15冠-5(No_2·B15C15)与过渡金属离子的配位能力,合成了Co(Ⅱ),Cu(Ⅱ),和Ag(Ⅰ)与4-硝基-苯并15冠-5配合物。并进行了元素分析,X-射线衍射,红外光谱,摩尔电导,激光拉曼光谱及差热-热失重分析的研究。     

二价铜、镍EDTA络合物晶体的电子吸收光谱

络合物晶体的电子吸收光谱作为研究晶体的电子结构的基础内容,很早以前就得到人们注意,虽然对Cu~(2+)、Ni~(2+)等络合物电子光谱的能级的经验指认已是一项较为成熟的工作,但对吸收光谱的系统的理论计算和定量解释在以前的文献中尚不多见.近年来,我们对多种晶体的电子吸收光谱进行了定量的解释,结果表明理论计算值总是能很好地符合于实验测定值。一般说来,吸收峰位的波数误差在8%以内. 早在本世纪四十年代就奠定了乙二胺四乙酸(EDTA)在分析化学中的应用基础。     

Synthesis, characterization and antifungal activity of copper (II) complexes of sterically hindered o-diphenol derivatives

Cu (II) complexes with 3,5-di(tert-butyl)-1,2-benzenediol (I), 4,6-di(tert-butyl)-1,2,3-benzentriol (II) and sulfur-containing sterically hindered o-diphenol derivatives such as 4,6-di(tert-butyl)-3-(2-hydroxyethylsulfanyl)-1,2-benzenediol (III) and 2-[4,6-di(tert-butyl)-2,3-dihydroxyphenylsulfanyl]acetic acid (IV) have been synthesized and characterized by means of elemental analysis, TG/DTA, FT-IR, ESR, XPS, XPD and conductivity measurements. Antifungal activities of these ligands and their respective Cu (II) complexes have been determined against Aspergillus niger, Fusarium sp., Penicillium lividum, Mucor sp. and Botrytis cinerea. Most of the compounds (both the free ligands and the complexes) exert pronounced antifungal activities (RI  70%), and virtually all of them (apart from the Cu(L^II)₂ complex) have the highest inhibitory properties (RI = 100%) against B. cinerea.     

A mixed metal phosphate incorporating isonicotinate ligand: synthesis, crystal structure, and magnetic properties of Cu(HINT)(VO2)(PO4)

A mixed metal phosphate incorporating isonicotinate ligand, Cu(HINT)(VO₂)(PO₄), was hydrothermally synthesized and characterized by single-crystal X-ray diffraction and magnetic susceptibility. This compound crystallizes in the monoclinic space group C2/c with cell parameters a=22.033(1) Å, b=6.2986(3) Å, c=16.0202(9) Å, β=121.001(1), and Z=8. The structure consists of two-dimensional neutral sheets of CuVO₂(PO₄) with the dipolar isonicotinate ligand being coordinated to Cu ions as a pendent group. Adjacent sheets are connected by hydrogen bonding. Each sheet consists of infinite chains of CuO₆ octahedra sharing trans edges which are connected by double chains of vanadyl(V) phosphate via corner sharing. Magnetic study results indicate the presence of intrachain ferromagnetic coupling between Cu ions. The magnetic exchange parameter was estimated as 2J/k =51.83 K based on an S=1/2 equally spaced ferromagnetic chain model.     

Koexistenzbeziehungen,Darstellung und Eigenschaften ternärer Phasen im System Cu/Mo/O

Coexistence Relations, Preparation and Properties of Ternary Compounds in the System Cu/Mo/O The phase diagram of the ternary system Cu/Mo/O is presented at 773 K. The compounds CuMoO₄, Cu₃Mo₂O₉, Cu₄Mo₅O₁₇, Cu₆Mo₅O₁₈, Cu_4–xMo₃O₁₂, and Cu_xMoO₃ are found to be thermodynamical stable. The homogeneity range of Cu_4–xMo₃O₁₂ runs to x = 0.1–0.2. Single crystals of CuMoO₄ and Cu₃Mo₂O₉ were grown by chemical transport reactions with TeCl₄, Cl₂, HCl, and Br₂ as transport agent. The results were compared with thermochemical calculations. The decomposition of CuMoO₄ and Cu₃Mo₂O₉ was investigated with thermal analysis and decompositon pressure measurements.     

Madaline网络用于分光光度法同时测定铜钴镍的研究

采用4－（2－吡啶偶氮）－间苯二酚（PAR）－Cu,Co,Ni显色体系，应用Madline神经网络原理，对于吸收光谱严重重叠的三组分金属配合物体系同时进行含量测定，Cu^2 ,Co^2 ,Ni^2 的平均回收率分别为94％，101％，102％，实验表明，该法具有训练速度快，预测结果准确度良好等特点，有望成为多组分分析的有效方法之一。     

Dissolution of copper foil in aqueous solution ofpH=2

The specific dissolution rate, expressed in mol cm^–2s^–1, and time-variation of the rest potential of copper foil in an aerated aqueous solution ofpH = 2.0 were measured.

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Die Auflösbarkeit von Kupfer-Folie in wäriger Lösung von pH 2 (Kurze Mitteilung)

Zusammenfassung Es wurde die spezifische Auflösungsgeschwindigkeit (in mol cm^–2s^–1) und die zeitliche Veränderung des Restpotentials von Kupfer-Folie in einer belüfteten wäßrigen Lösung von pH 2,0 gemessen.

     

Copper-catalyzed coupling of aryl halides and nitrite salts: a mild Ullmann-type synthesis of aromatic nitro compounds

Nitration of aromatic halides proceeded smoothly in the presence of catalytic amounts of Cu bronze and N,N′-dimethylethylenediamine. Sodium nitrite-18-crown-6, or tetra-n-butylammonium nitrite (n-Bu₄NNO₂) turned out to be efficient nitrating agents. The aromatic nitro compounds were synthesized under essentially neutral conditions.