用于环酯单体开环聚合的无金属引发/催化体系

环酯单体在不同引发/催化体系作用下的开环聚合是制备可生物降解脂肪族聚酯的主要方法.综述了近年来用于环酯单体开环聚合的无金属引发/催化体系,主要涉及水、醇、胺、羧酸等引发剂及质子酸、膦类、氮杂环类化合物等催化剂体系.     

Two Cyclic Peptides Produced by the Endophytic Fungus # 2221 from Castaniopsis fissa on the South China Sea Coast

New cyclic peptides 1 and 2 were isolated from the endophytic fungus #2221 from Castaniopsisfissa on the south China sea coast. By 2D NMR methods and chiral HPLC technique, their structures were elucidated as cyclo (L-Val-L-Leu-L-Val-L-Leu) and cyclo(L-Leu-L-Ala-L-Leu-L-Ala), respectively.     

General synthesis of n-membered cyclic sulfamides

A general method for the synthesis of n-membered cyclic sulfamides (cyclosulfamides) is described. An application to the synthesis of constrained peptidal cyclic sulfamide is illustrated.     

聚苯胺修饰电极制备过程中几个问题的探讨

报道聚苯胺修饰电极制备中尚须引起人们重视的几个问题。主要包括：循环伏安法扫描电位上限对聚合的影响，恒电位法最佳的聚合电位，以及仅具２００ｍＶ和９００ｍＶ两峰聚苯胺膜的制备，聚合电量对不同制备方法影响的差异性等等。并对制备聚苯胺修饰电极的几种方法进行了比较，从而指出了最佳的聚合方法和条件。     

Electron-transfer induced change of direction of interannular haptotropic isomerization of fluorenyltricarbonylchromium anions

It has been shown by cyclic voltammetry in a THF medium in the temperature range from –70 °C to +20 °C that one-electron electrochemical reduction of (⁶-C¹³H¹⁰)Cr(CO)₃ (1) to the corresponding 19-electron anion radical (1 ^–) is accompanied by splitting off of a H atom to form the 18-electron carbon-centered anion (⁶-C₁₃H₉)Cr(CO)₃ (^–2 ), which at room temperature undergoes intramolecular haptotropic isomerization to the metal-centered (⁵-C₁₃H₉)Cr(CO)₃ ^– (^– 3) anion. The reversible one-electron reduction of3 ^– to the corresponding 19-electron radical dianion3 ^2.– induces ^{5 6} interannular isomerization. In contrast to the equilibrium shift to the ⁵-isomer in 18-electron complexes 2 and 3, in their 19-electron analogs the equilibrium is shifted to the ⁶-isomer.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 48–53, January, 1994.This work was carried out with financial support from the Russian Foundation for Basic Research (no. 93-03-5209)     

Transformation of biodegradable polyesters into cyclic oligomers under continuous flow using an enzyme-packed column

The enzymatic degradation of typical chemically synthesized biodegradable plastics, such as poly(butylene adipate) and poly(epsilon-caprolactone), to a repolymerizable cyclic oligomer under continuous flow using an enzyme column was studied, directed towards green chemical recycling. It was confirmed that both polymers were quantitatively transformed into the corresponding cyclic oligomers by passage through the column packed with immobilized lipase from Candida antarctica (Novozym 435) at 40 degrees C using a toluene solution. Compared to the batch treatment in a flask, a short reaction time and a low reaction temperature occurred for complete transformations of the polyesters by continuous flow through the enzyme column. The degradation activity of the enzyme column was maintained for at least six months at 40 degrees C. Conceptual scheme of the continuous degradation equipment using the enzyme column.     

Novel Fluorine Containing Tetrathiafulvalenes for the Preparation of Langmuir-Blodgett Films

The novel fluorinated tetrathiafulvalenes: tetra(2,3,5,6-tetrafluorobenzylthio)-, dimethyldi(2,3,4,5,6-pentafluorobenzylthio)-, dimethyldi(2,3,5,6-tetrafluorobenzylthio)-, dimethyldi[3,5-di(trifluoromethyl)benzylthio]-, and dimethyldi(2-fluoro-4-bromobenzylthio)tetrathiafulvalenes have been synthesized in order to prepare Langmuir-Blodgett films. Their cyclic voltamograms have been studied and these show two, reversible, one-electron oxidation waves. A novel series of fluorinated benzylthio- and benzoylthio-1,3-dithiole-2-thiones and -2-ones has been synthesized.     

化学和电化学方法合成苯/胺封端苯胺四聚体

利用改进了MacDiarmid氧化偶联方法合成了苯／胺封端的苯胺四聚体，通过对循环伏安曲线的分析，给出二聚体经由电化学氧化－化学偶联成为四聚体的机理，利用基质辅助激光解吸质谱和红外光谱对产物进行了表征。     

新型正极材料三硫代环磷氮烯无机聚合物的合成

采用缩合聚合方法合成了新型三硫代环磷氮烯无机聚合物[(NPS₃)₃]_n，利用红外光谱测试与元素含量分析技术证明了[(NPS₃)₃]_n的分子结构与组成，并对聚合物材料的粒度、比表面积及微观形貌进行了考察。TG/DTA 实验证明材料在200 ℃ 以下具有良好的热稳定性。循环伏安测试表明[(NPS₃)₃]_n正极材料在锂电池体系具有2.15 V的电化学还原电位和2.45 V的电化学氧化电位，经充放电循环实验观察，材料的首次放电容量达到749.0 mAh·g^-1，与理论容量(759.0 mAh·g^-1)十分接近；经过50次充放电循环后，放电容量保持在674.8 mAh·g^-1，具有很高的使用容量和优秀的循环性能。     

Cyclodextrine und synthetische Wirthohlräume — Vergleich der Komplexierungseigenschaften

It is shown that the synthetic host compounds described in this study possess higher complexation constants versus 1,8-ANS than -or -cyclodextrin. The attachment of side chains to -cyclodextrin increases the complex formation, whereas the value of -cyclodextrin is not reached. The quaternary ammonium nitrogens of the synthetic hosts may be replaced by amide groups without diminution of the association constants. Bicyclic compounds in general bind more strongly than monocyclic hosts due to tighter inclusion and increased hydrophobic interaction. The influence of side chains attached to synthetic host compounds on the complexation constants is difficult to predict.