三阶导数分光光度法同时测定铜,钴与镉

采用三阶导数光谱技术，以ｍｅｓｏ－四（４－三甲铵基苯基）卟啉作显色剂分光光度法同时测定了微量的铜、钴与镉。方法中以铅离子掩蔽过剩试剂的吸收峰，然后进行三级微分求导，可以使铜、钴、镉吸收峰完全分开，于４１５ｎｍ、４３４ｎｍ及４３８ｎｍ处同时测定３元素含量，由三阶导数光谱的吸光值可求算出配合物的三阶导数摩尔吸光系数分别为：１．１１×１０６、３．９５×１０５及６．４７×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。     

Ba8Cu16P30 – eine neue ternäre Variante des Clathrat I-Strukturtyps

Ba₈Cu₁₆P₃₀ – a New Ternary Variant of the Clathrate I Type Structure Ba₈Cu₁₆P₃₀ (a = 14.117(1) Å, b = 10.093(1) Å, c = 28.022(2) Å) was prepared by heating a mixture of the elements (800°C; excess of Ba and P; removal of the by-products by acetic acid/H₂O₂). The compound crystallizes orthorhombically (Pbcn; Z = 4) in a new superstructure of the cubic clathrate I type structure with an ordered distribution of the atoms. The structure is characterized by a three-dimensional framework of CuP₄ tetrahedra with cavities in the form of pentagonal dodecahedra and tetrakaidecahedra, which are occupied by the Ba atoms. The compound shows semiconduction, therefore the composition should be Ba₈Cu_15.5P_30.5.     

硫胺的燐光研究

硫胺无燐光，在碱中氧化后才产生燐光。 λ激发＝３００ｎｍ，λ发射＝４１０ ｎｍ，燐光寿命为１．３ｓ．硫胺燐光受溶剂极性影响甚小，１５种金属离子中只有铜离子可增强流胺燐光，寿命变短为 ０． ９４ ｓ，但不影响燐光光谱。在开始３０ｍｉｎ内有ＣｕＳＯ４的作用较快，以后逐渐变慢，到 ４ｈ后达平衡与不用ＣｕＳＯ４的燐光相近，启示ＣｕＳＯ４具有催化硫胺的氧化作用，建立了硫胺的燐光分析方法，用于两种维生素Ｂ１片的分析，分别为９８．５％与９８％。     

铜(Ⅱ)-邻菲咯啉-(邻菲咯啉-5,6-二酮)络合物的合成及其同脱氧核糖核酸的作用

以邻菲咯啉（phen)、邻菲咯啉－5，6－二酮（dione)为配体首次合成了高氯酸邻菲咯啉－邻菲咯啉－5，6－二酮（Ⅱ）。用荧光光谱，摩尔比，粘度，MLCT减色效应，平衡常数以及荧光能量转移研究了各合物与鱼精子DNA的结合情况，证实了该络合物与DNA存在插入作用。基于络合物对DNA能量转移造成荧光量子产率比值（Φλ/Φ320）的降低，解释了不同波长激发光下，荧光发射峰在加入DNA后产生猝灭和增强两种绝然不同的现象。     

Effect of carbonate incorporation on the structural and superconducting properties of the double chain compound Y2Ba4Cu7O15−x

Structural investigations on powder samples of Y₂Ba₄Cu₇O_15–x with different carbonate content have been performed. Powder x-ray Rietveld refinements showed the remarkable influence of carbonate incorporation on the lattice parameters. Most important is the decrease of T_c with increasing carbonate content. We assign these effects to an incorporation of the carbonate ion into the crystal lattice, copper vacancies at the Cu(1) position and a possible misorientation of the copper oxygen single chains. No change of the structure (e. g. superstructure) could be found.     

Preconcentration Systems Using Polyurethane Foam/Me-BDBD for Determination of Copper in Food Samples

A new reagent, 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid (Me-BDBD), was synthesised and used in on-line and off-line systems for copper preconcentration by solid-phase extraction. Spectrophotometry and Flame Atomic Absorption Spectrometry (FAAS) were the detection techniques. Polyurethane foam loaded with Me-BDBD packed in a minicolumn was used as sorbent in both systems. The spectral characteristics of Me-BDBD were investigated. The optimum pH values for maximum sorption of the metal are between 7.0 and 8.5. Copper was desorbed with 0.05 and 0.50 mol L⁻¹ hydrochloric acid solutions, for on-line and off-line systems, respectively. The effects of several foreign substances on the adsorption of copper are reported. The enrichment factors obtained were 7 (on-line) and 26 (off-line) for the systems. The proposed procedures allowed the determination of copper with detection limits of 3.4 and 1.4 μg L⁻¹ (0.85 and 0.35 μg per gram of sample) for on-line and off-line systems, respectively. The precision of the procedures was also calculated: 3.2 (on-line) and 1.9% (off-line). The validation of the procedures was carried out by analysis of certified reference material. The copper contents in corn and rice flour and black tea samples were determined by applying the proposed procedures.     

Synthesis and Crystal Structure of the Copper Complex of 7，16-Bis（2-hyd roxy-5-met hylbenzyl）-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane

A lariat crown ether ligand 7,16-bis (2-hydroxy-5-methylbenzyl)- 1,4,10,13-tetraoxa-7,16-diazacyclooctadeeane (L1) has been prepared via one-pot Mannich reaction. Its copper(Ⅱ) complex Cu-L1 was synthesized and characterized by elemental analysis, IR and UV-visible spectroscopy. The crystal structure of the complex has been determined by X-ray diffraction analysis. The result shows that the copper(Ⅱ) ion is six-coordinated by two nitrogen and four oxygen atoms, two from the crown ether and the other two from the deprotonated phenolate anions, forming an elongated octahedral complex. Electrochemical study indicates that the complex undergoes reversible reduction in DMF solution.     

负载型CuO—ZnO／γ—Al2O3催化剂抗硫中毒性能的研究

采用XPS、TPR法证明浸渍法制备的CuO-ZnO/Al_2O_3催化剂中的CuO、ZnO和γ-Al_2O_3之间存在强相互作用,Cu量≤7.0wt%,Zn量≤11Wt%时,CuO和ZnO以单分子层分散在γ-Al_2O_3上.催化剂表面Cu和Zn实际含量的比值远小于配制时的比值(Cu/Zn=2),表明ZnO比CuO优先分布在表面.因ZnO比CuO更易和S作用生成ZnS,ZnO在表面的大量存在减少了Cu被S中毒的机率;另外CuO单层分散在Al_2O_3上,还原后生成的Cu~0,由于γ-Al_2O_3的拉电子作用使其处于缺电子状态(CU~(?+)),加上催化剂表面可能有部分CuO和Al_2O_3形成尖晶石,使一部分Cu以Cu~(n+)存在,Cu~((?)+)或Cu~(n+)对S的吸附弱.以上两个原因使负载型铜催化剂具有良好的抗硫中毒性能.     

Syntheses, Structures, and Nonlinear Optical Properties of Two Crown-like Heteroselenometallic Compounds [Et4N]4[(μ5-WSe4)(CuX)5(μ-X)2] (X = Cl, Br)

Two isostructural crown-like heteroselenometallic cluster compounds, [Et₄N]₄[(μ₅-WSe₄)(CuX)₅(μ-X)₂] (X = Cl 1, Br 2), were prepared from the reactions of [Et₄N]₂[WSe₄] with CuX and [Et₄N]X· xH₂O in the presence of 2-picoline and characterized by single-crystal diffraction analysis. The [(μ₅-WSe₄)(Cu-X)₅(μ-X)₂]⁴⁻ anions in the cluster compounds consists of five CuX fragments coordinated to the five edges of the tetrahedral [WSe₄]²⁻ moiety along with two bridging halides connected to each of the two pairs of the symmetric copper atoms, exhibiting a novel crown-like core structure. The nonlinear optical absorption and refraction of cluster compound 2 were determined to be α₂ = 6.15 × 10⁻¹⁰ m/W and n ₂ = 4.18 × 10⁻¹¹ esu, respectively.     

Catalytic olefination reaction of carbonyl compounds. A study on stereoselectivity of alkene formation

The mechanism of formation of alkene stereoisomers in the catalytic olefination reaction of carbonyl compounds was studied. 4-Chlorobenzaldehyde hydrazone 1 stereoselectively reacts with a number of F-, Cl-, Br-, and I-containing polyhaloalkanes in the presence of catalytic amounts of CuCl to give -substituted styrenes 2 with the more thermodynamically stable alkene isomer being the major product. A model for the formation of the stereoisomers of alkenes 2 in the olefination reaction is proposed. Stereoselectivity of the reaction is determined by elimination of copper(ii) halides from the lowest-lying conformers of organocopper intermediates II. According to quantum-chemical calculations, the elimination should involve the staggered conformations with antiperiplanar arrangement of C—Hal and C—Cu bonds and proceed by the E2 anti-elimination mechanism. The results of quantum-chemical calculations are in good agreement with the experimental E/Z alkene isomer ratios.