Two noncentrosymmetric complexes: [W(CO)4(bipy)] and [W(CO)4(phen)](bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline) obtained through solvothermal synthesis and their optical properties

Solvothermal treatments of W(CO)₆ with 2,2′-bipyridine and 1,10-phenanthroline give [W(CO)₄(bipy)] (1) and [W(CO)₄(phen)] (2), respectively, which both crystallize in noncentrosymmetric space groups, suggesting that they meet the requirement of second harmonic generation (SHG) investigations. The preliminary experiment indicates that they are SHG active, and approximately estimated to be that of urea.     

稀土冠醚配合物的研究ⅩⅩⅠ.单羟基冠醚与钙、稀土元素间的竞争配位及其钙配位化合物的晶体结构

研究了单羟基冠醚配位体6-羟基-2,3,9,10-二苯并-1,4,8,11,14-五氧杂环十六-2,9-二烯(L)对钙和镧系元素的竞争配位反应,发现该配位体在我们的实验条件下对钙的配位能力要明显大于对重稀土的配位能力;同时研究了标题大环配位体和钙的配位化合物的晶体结构,该配位化合物的分子结构式为[Ca(NO3)(H2O)L](NO3),Mr=528.47,晶体属单斜晶系,a=1.5285(6),b=0.9713(3),c=1.5134(7)nm,β=98.79(3)°,V=2.2205nm3,Dex=1.531g/cm3,Dc=1.527g/cm3,Z=4,空间群为P21/c.     

Liquid-liquid Extraction System Based on Non-ionic Surfactant-salt-H_2O and Mechanism of Drug Extraction

The utilization of solid-liquid extraction system based on polymer-(NH4)2SO4 -H2O on separation of metal ions and bio-active substances has been summarized1. Cloud point extraction (CPE) benefits the environment and has been used in separation of metal chelates, biomacromolecules and in pretreatment of environmental samples2-4. In a 10 mL color comparison tube 20% PEG-1000 and 2.5 g (NH4)2SO4 were chosen as phase separation condition at pH 5.5. The average extraction efficiencies we…     

HZSM－20沸石分子筛的水蒸汽改性

ＨＺＳＭ－２０沸石分子筛的水蒸汽改性项寿鹤，任大立，王敬中，李赫晅（南开大学化学系，天津３０００７１）关键词ＨＺＳＭ－２０沸石，水蒸汽处理，改性ＺＳＭ－２０沸石是一种具有大孔和开放结构的分子筛［１］，其结构与八面沸石（如Ｙ型沸石）类似，但其硅铝比较高...     

Quantitative proteomics strategy involving the selection of peptides containing both cysteine and histidine from tryptic digests of cell lysates

This paper describes a procedure for quantitative proteomics that selects peptides containing both cysteine and histidine residues from tryptic digests of cell lysates. Cysteine-containing peptides were selected first by covalent chromatography using thiol disulfide exchange. Following the release of cysteine-containing peptides from the covalent chromatography column with reductive cleavage, histidine-containing peptides were captured by passage through an immobilized metal affinity chromatography column loaded with copper. Quantification was achieved in a four-step process involving (i) differential labeling of control and experimental samples with isotopically differing forms of succinic anhydride, (ii) mixing the two globally labeled samples, (iii) fractionating the labeled peptides by reversed-phase liquid chromatography, and (iv) determining the isotope ratio in individual peptides by mass spectrometry. The results of these studies indicate that by selecting peptides containing both cysteine and histidine, the complexity of protein digests could be substantially reduced. Up-regulated proteins from plasmid bearing Escherichia coli that had been induced with isopropyl beta-thiogalacto-pyranoside were identified and quantified by the global internal standard technology (GIST) described above. Database searches were greatly simplified because the number of possible peptide candidates was reduced more than 95%.     

Methane Combustion Over Fe, Co and Ni Modified Manganese Oxide Catalysts

Fe-Mn, Co-Mn and Ni-Mn composite oxide catalysts based on high specific surface area MnO₂ precursor were prepared and applied to catalytic combustion of CH₄. Results were compared with that of unmodified MnOx and 1wt.% Pd/-Al₂O₃. Below 450°C, manganese oxide catalysts show higher activity than Pd/-Al₂O₃, while the modified manganese oxide catalysts exhibit higher activity than the unmodified one below 420°C. All catalysts were characterized by means of N₂-BET, XRD, TG-DTA and H₂-TPR. Due to the interaction between Fe, Co or Ni oxides and manganese oxide, the activity of the oxygen species of the modified catalysts is improved, which leads to the increase of their CH₄ combustion activity.     

新型显色剂3,3,5,5''''-四甲基联苯胺分光光度法测定余氯的研究

本文报道了采用新型氧化还原剂3,3’,5,5’-四甲基联苯胺(TMB)测定水中总余氯的分光光度法,并对其灵敏度、稳定性、准确性作了较为详细的研究,探讨了分析条件,提出了分析方法。在pH≤2时,最大吸收峰为450 nm,表观摩尔吸光系数为6.89×10~4L·mol~(-1)·cm~(-1),可测范围为0.01～2.5 mg/L。与目前使用的传统显色剂邻联甲苯胺(DMB)相比较,具有灵敏度高,显色稳定,重现性好及使用安全等优点。     

吖啶类衍生物的荧光性质

用比较法测得23种啶类衍生物的荧光量子效率（Φf)，以评估这些化合物的荧光性质，结果表明，N－烃基吖啶酮类化合物的荧光量子效率要比9－取代苯基吖啶类和9－取代苯亚甲基－10－甲基－9，10－二氢吖啶类化合物的荧光量子效率大，在非极性溶剂中，9－聚代苯亚甲基－9，10二氢吖啶分子内的强吸电子基NO2增强荧光量子效率，强推电子基OCH3降低荧光量子效率，这些测量结果与取代基的电子作用经验规律不相符，这种现象可以用分子内电荷转移理论进行解释。     

丙氨酰-谷氨酰胺的简便有效合成

谷氨酰胺 (Ｇｌｎ)是肠道必需氨基酸 ,是肠粘膜细胞氧化的重要燃料。肠粘膜缺乏Ｇｌｎ将严重损伤肠屏障功能 ,创伤性休克及化疗应激可加重损害 ,导致肠粘膜萎缩 ,肠道细菌移位 ,甚至促发脓毒症和多器官功能不全 (ＭＯＤＳ) [1] 。但Ｇｌｎ性质不稳定 ,不能耐高温消毒 ,因此 ,一般氨基酸制剂不含Ｇｌｎ。Ａｌａ Ｇｌｎ为Ｇｌｎ代谢前体 ,溶解度高 ,性质较Ｇｌｎ稳定 ,能耐受热灭菌 ,在体内数分钟即分解出Ｇｌｎ ,能部分补偿肠道所需Ｇｌｎ ,减少严重创伤及腹腔注射化疗药物 5 氟尿嘧啶 (5 ＦＵ)引发的小肠粘膜形态功能改变 ,细菌移位 ,降低…