轴手性化合物R/S构型标记的一种简易方法

旋光异构是有机化学立体异构中一个十分重要的异构现象,在旋光异构中有一类不含有手性原子的轴手性化合物,本文提出了一套快速而准确标记该类轴手性化合物R/S构型的简要步骤,并进行实例分析

Synthesis of Olefinic Carbolong Complexes

碳龙配合物是一类崭新的金属杂芳香化合物,具有新颖的结构和独特的性能,有着很好的潜在应用前景.然而,已报道的碳龙配合物绝大部分不带有可进一步化学修; 饰的有机官能团.此状况阻碍了其进一步化学修饰和实现功能材料化的应用研究.烯烃基团是一类高活性有机官能团--可发生高转化率的聚合反应、点击反应等多; 种有机反应.为此,合成烯基化的碳龙配合物,可实现这类新颖分子的有机功能团化,对其后续实际应用有着重要的意义和价值.利用锇杂戊搭炔的反应性以及合成; 底物的修饰,设计合成了一系列烯基化的碳龙配合物,并对其进行了系统表征.Carbolong complexes are a new type of metalla-aromatic compounds with novel skeleton and interesting properties, which could be used as potential interesting materials. However, most of them do not have reactive organic functional groups, which hinder their applications as functional materials via chemical modifications. Olefinic group is a reactive functional group that can be used for polymerization or click reaction and so on. In this work, the synthesis of carbolong complexes attached an olefinic group, which could be used to prepare carbolong-containing materials, is reported based on their reactivity.National Natural Science Foundation of China [21490573, 21332002,; 21472156

原子力显微镜在高分子领域的应用进展

原子力显微镜(AFM)是在扫描隧道显微镜(STM)基础上发明的又一种纳米级高分辨率显微技术,目前已在高分子领域获得了广泛的应用.AFM无需对样品进行任何预处理即可对各种材料进行微观区域的表面形貌及机械性能探测,或者直接进行纳米操纵.本文则从表征聚合物聚集态、物理性质、分子量及其分布等几个方面综述了当前AFM应用于高分子材料研究的最新进展和新技术

Development of polymer precursors to SiC ceramic fiber

先驱体转换法是迄今为止高性能SiC陶瓷纤维最为成功的一种工业化方法,而高聚物先驱体的结构与性能则是该法的关键。本文主要综述了国内外SiC陶瓷纤维高聚物先驱体分子设计方面的研究动态及最近的发展趋势。The most successful route up-to-date to prepare SiC ceramic fiber in industry is the polymer precursor route; whereas the performance and the molecule structure of polymer precursors play a key role in this method. This article reviews the recent develpment of molecule structure design of polymer precursors

Investigation on solvent extraction method to regulate molecular weight and its distribution of polycarbosilane

[中文文摘]真空热处理法去除聚碳硅烷(polycarbosi-lane,PCS)小分子时,因伴随着化学反应导致PCS结构变化而降低其纺丝性能。溶剂浸提法则无此之虞。研究结果表明,不同溶剂对PCS的溶解能力是不同的,依次为:甲醇<二甲基甲酰胺<乙二醇单甲醚<无水乙醇<乙二醇单乙醚<异丙醇<甲酸乙酯<乙酸甲酯<正丙醇。这一溶解能力体现为可溶PCS量的不同和可溶PCS分子量的不同两个方面。溶解能力较大的溶剂可以溶解分子量较大的PCS;溶解量也较多。由于溶剂的这一特性,溶剂浸提法不仅可以用来去除小分子的PCS,而且可以用来调节PCS的分子量及其分布,改善其纺丝性能,提高其原丝强度,而不改变PCS的分子结构。[英文文摘]When vacuum heating method is used to remove the low molecular weight fraction from polycarbosilane(PCS),the accompanied chemical reaction will occur during this processing,usually the reaction will change the structure of PCS and lead to reduce its spinnability.This defect can be avoided by using the solvent extraction method to supersede the vacuum heating method.The results of this study indicated that: the solubility of PCS is different in different solvent.The solution power of solvents to PCS in the ascending order is methanol, N ,N-dimet hylformamide , 2-methoxyethanol , ethanol , 2-ethoxyethanol , 2-propanol , ethyl formate, methyl acetate and n-propanol. The solution power of solvents to PCS includes soluble amount and soluble mo- lecular weight of PCS. The higher solution power of solvent s gives larger amount and higher molecular weight of soluble PCS. Base on this property of solvents , the solvent extraction method can be used to remove the low molecular weight f raction f rom PCS and also can be used to regulate the molecular weight and its distribution of PCS , which will improve the spinnability of PCS and the strength of green fiber while the structure of PCS remains unchanged.国家自然科学基金重点资助项目(50532010); 福建省自然科学基金计划资助项目(2008J0165)

从XY雌鱼雌核发育产生YY超雄黄颡鱼

采用激素性逆转结合雌核发育技术,从XY雌鱼产生YY超雄黄颡鱼。与性逆转和后代测交选种技术比较,本文的方法可以缩短两代的育种时间,并提高超雄鱼的产出。通过测交证明,与正常的XY雄鱼一样,YY超雄黄颡鱼是能成活和有生育力的,其后代雄鱼占75.9%&mdash;100%,平均90.30%。从29尾雌鱼产生的雌核发育的后代294尾,只有11尾雄鱼,绝大多数是雌鱼;而在12尾YY超雄鱼测交的后代出现0&mdash;24.1%雌鱼。从上述结果可以推测,黄颡鱼的性决定体制是雌性配子同型(XX♀/XY♂),但常染色体性修饰基因的影响是比较明显

LIVING FREE-RADICAL POLYMERIZATION IN THE PRESENCE OF DITHIOESTERS

[中文文摘]合成并研究了两种双硫酯链转移剂的纯化方法 ,进行了多种单体以双硫酯为链转移剂的活性自由基聚合及嵌段共聚 .发现以PhC(S)SC(CH3) 2 Ph为链转移剂的效果比PhC(S)SCH(CH3)Ph好 ,聚合产物的多分散性系数较小 .引发剂与链转移剂的摩尔数比为 1∶3 5～ 1∶4 2时 ,得到多分散性系数小 ,实测分子量与理论分子量相近的聚合产物 .聚合物的分子量随时间和转化率的增加而增加 ,加入第二单体形成嵌段共聚物 ,具有活性聚合特征 .聚甲基丙烯酸酯大分子引发剂引发丙烯酸酯单体聚合时 ,聚合速度最快.[英文文摘]A series of monomers (methacryle,acrylate and styrene) were polymerized by controlled/living radical polymerization in bulk using Reversible Addition\|Fragmentation chain transfer (RAFT process).A detail purification process of chain transfer agent (CTA) dithioesters (2\|phenylprop\|2\|yl dithiobenzoate and 1\|phenylethyl dithiobenzoate) was described.Results of styrene (St),methyl methacrylate (MMA),ethyl methacrylate (EMA),butyl methacrylate (BMA),octyl methacrylate (OMA),methyl acrylate (MA),ethyl acrylate ( EA) polymerization using the AIBN/ CTA (mole ratio 1 ∶4) initiating system at 70 ～ 100 ℃ confirmed the living polymerization characteristics. Diblock copolymers ( PMMA2PEMA , PEMA2PMMA , PBMA2PMA ,PBMA2PEA ,PSt2PBA) with well defined st ructures as well as cont rolled and narrow molar mass dist ribution were obtained f rom the lower-mass macroinitiator. The living character of the RAFT process is indicated by the narrow polydispersity product (1. 1～1. 3) ,a linear molecular weight2conversion profile ,the predictability of the molecular weight f rom the ratio of monomer consumed to t ransfer agent and the ability to produce block copolymer by further monomer addition. In each reaction step , the effects of conversion and reaction time on the molar mass characteristics of the prepared block copolymers were investigated. The SEC curves shift toward lower elution volumes as the reaction time increases. While the polydispersity remained low and there was no detectable amount of unreacted starting macroinitiator block as analyzed by GPC. When high molecular weight starting macroinitiator ( Mn > 30000) was used ,there was a substantial low molecular weight shoulder observed

具有光热性能的碳龙配合物材料（英文）

金属有机化合物很少作为光热材料.报道一系列碳龙配合物的合成及其光热性能,将OsCl2（PPh3）3与有机多炔碳链反应获得金属杂戊搭炔,再与末端炔烃发生[2+2]环加成反应得到此类碳龙配合物--锇杂戊搭烯并环丁二烯.这些共轭的金属杂环化合物在紫外-可见区具有宽吸收并表现出优异的光热性能,有望成为一类新型的光热材料.Project supported by the National Natural Science Foundation of China(Nos.21302158,U1705254,21490573)~