Ionic-liquid-supported peptide synthesis demonstrated by the synthesis of Leu(5)-enkephalin

A new strategy for the synthesis of oligopeptides was developed using an ionic liquid as a soluble support. The efficiency of this ionic liquid-phase approach was demonstrated by the synthesis of a bioactive pentapeptide, Leu(5)-enkephalin, in good yield and reasonable purity. The structures and purities of the reaction intermediates in each step were verified easily by routine spectroscopic analysis, and no chromatographic procedures were needed during the synthesis.     

Kinetic investigation of the textile bleaching process

Volumetric H₂-uptake measurements on an Mo₂N (79 m²g^–1) sample reduced at 673 K have been carried out and the uptake isotherms in the temperature range of 308–623 K have been determined. Both the total and reversible hydrogen uptake increased with the uptake temperature. The irreversible hydrogen uptake increased abruptly when the uptake temperature was raised up to 423 K. The maximum of irreversible hydrogen uptake was measured at 473 K. The H_IR/Mo ratio calculated from the uptakes obtained in the temperature range of 308–623 K varies in the range of 0.0010–0.0202. One possible mechanism for hydrogen adsorption is proposed to be heterolytic dissociation on Mo-N paris, in which the molybdenum atoms are in unsaturated coordination.     

新显色剂二溴硝基苯基重氮氨基偶氮苯的合成及与镉的显色反应的研究

作者合成了新显色剂2,6-二溴-4-硝基苯基重氮氨基偶氮苯(DBNDAA)。在pH8.5的硼砂-盐酸缓冲介质中,在Tween 80-SDBS存在下,该试剂与镉(Ⅱ)生成络合比为3:1的红色络合物,λ_(max)=500nm,ε_(500)=1.52×10~5L·mol~(-1)·cm~(-1)。镉量在0～28μg/25ml范围内遵守比耳定律。并测定了试剂的表观离解常数和络合物的表观不稳定常数。方法有良好的选择性。用该试剂测定了铝合金标样、环境水样及废水中的痕量镉,结果满意。     

μ酰基铁硫配合物亲核取代反应的研究——若干三苯膦或三苯胂μ酰基铁硫配合物的合成及结构

μ-酰基铁硫配合物(μ-ArCO)(μ-RS)Fe_2(CO)_6和PPh_3在苯中迴流2小时, 或和AsPh_3在苯中迴流12小时可分别制得相应的单取代衍生物(μ-ArCO)(μ-RS)Fe_2(CO)_5 PPh_3(Ar=Ph, R=Et或B_u~t; Ar=p-ClC_6H_4, R=B_u~t)和(μ-ArCO)(μ-RS)Fe_2(CO)_5AsPh_3(Ar=Ph, R=Et或B_u~t).除用碳氢分析, IR和~1HNMR光谱表征了这五个新取代衍生物的结构外, 还测得一个代表物(μ-p-ClC_6H_4CO)(μ-B_u~t S)Fe_2(CO)_5 PPh_3的单晶结构. 该晶体属三斜晶系, 空间群P1. 晶胞参数a=1.0536(2), b=1.1714(4), c=1.4841(8) nm; α=98.47(4), β=102.70(4), γ=105.78(3)°; V=1.6771 nm; Z=2; D_C=1.468 g·cm~(-3). 最终偏离因子R=0.065.     

Determination of V(V), Nb(V) and Ta(V) as their 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol chelates by reversed-phase HPLC

This paper reports the separation and determination of V(V), Nb(V) and Ta(V) by RP-HPLC using 5-Br-PADAP as a precolumn derivatizing reagent. On C(18) column, the three metal chelates can be separated on a baseline in 9 min with the mobile phase of methanol-water (59:41, v/v) containing tartaric acid (0.2%) and acetate buffer (pH 3.5, 10 mM). The detection limits of V(V), Nb(V) and Ta(V) are 0.13 ppb, 0.22 ppb and 1.79 ppb, respectively when S/N is 3. This method is simple and rapid, and has been used in mineral analysis with satisfactory results.     

四碘代对苯二甲酸根桥联的双钴(II)配合物的研究

报导了四种新的双核钴（Ⅱ）配合物，即［Co2（4I-TPHA）（L）4］（COl4）（4I-TPHA＝四碘代对苯二甲酸根阴离子，L＝1，10菲咯啉（phen）（1），5-硝基-,10菲咯啉（NO2-phen）（2），2，2′-联吡啶（bpy）（3）和4，4′-二甲基-2，2′-联吡啶（Me2bpy）（4）的合成和表征，配合物的磁性研究表明双核钴（Ⅱ）离子间有弱的反铁磁性自旋交换相互作用。     

CeO2—LnO1.5固溶体的表征及其甲烷催化燃烧性能

向CeO2中引入Ln3 离子后形成的CeO2－LnO1.5（Ln=La，Nd，Sm，Gd）固溶体（n（Ce）：n（Ln）=1：1）是一种无贵金属的新型高效甲烷燃烧催化剂．比表面、XRD、Raman、TEM等分析证实，这类固溶体具有部分畸变的萤石结构，Ln3 进入晶格后诱发的结构变化使得团溶体的表面和本体能同时参与氧化还原反应．实验表明，该固态溶液体系是甲烷催化燃烧的良好催化剂．     

Novel fragmentation reaction of correolide

[reaction: see text] Pentacyclic triterpenoid natural product correolide (1) was converted to ketone 2 via ozonolysis. An unusual fragmentation reaction of ketone 2 with LiCl was discovered. This reaction is general among several similar substrates examined and appears to be specific for the correolide-type E-ring structure (ketone). A mechanism involving a retroaldol reaction, a nucleophilic opening of the epoxide, and a subsequent acetoxy elimination reaction was proposed.     

利用无水乙醇分解制备碳纳米管

利用CVD法高温分解无水乙醇,以分子筛（合成皂石）基体上的Fe颗粒为催化剂,制备出了管壁更薄、端部为开口结构的碳纳米管.本实验制备出的碳纳米管,相对于传统CVD方法制备出的碳纳米管,在实验条件控制稳定的情况下,管壁较直、缺陷较少、管内径较大.具有这样结构的碳纳米管在储氢等方面应具备更为优良的效果,从而有着潜在的应用前景.     

Immobilization of copper in organic-inorganic hybrid materials: a highly efficient and reusable catalyst for the Ullmann diaryl etherification

The immobilization of copper in organic-inorganic hybrid materials catalyzing the Ullmann reaction has been described. Phenols reacted with aryl iodides, aryl bromides and aryl chlorides smoothly in the presence of a 3-(2-aminoethylamino)propyl functionalized silica gel immobilized copper catalyst. The protocol involved the use of DMSO as the solvent, and potassium fluoride as the base. The reactions generated the corresponding cross-coupling products in good to excellent yields. Furthermore, the silica-supported copper could be recovered and recycled by a simple filtration of the reaction solution and used for 10 consecutive trials without loss of its reactivity.