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1.
聚酰亚胺LB膜研究进展   总被引:4,自引:0,他引:4  
聚酰亚胺(PI)是一种高性能聚合物材料,通过Langmuir-Blodgett膜(LB膜)技术实现PI分子排列的有序化,可以使PI的某些性能更充分体出现来,详细总结了PILB膜的制备方法,对其在气体分离,光敏性,液晶取向,介电以及光电导等方面性质的研究现状进行了较为全面的综合,对PILB的研究和应用前景作了简要展望。  相似文献   

2.
通过变温红外光谱对反铁电液晶MHOCPOOB薄膜相变过程中的分子构象、排布及相互作用的变化进行了研究.结果表明,室温时,薄膜中的分子烷基链同时含有zigzag和gauche两种构象.随着温度的升高,有序的zigzag构象转化为无序的gauche构象,链的扭曲程度增加.但S*IA到S*CA的转变并不引起烷基链构象和取向发生明显变化.刚性核中的羰基与相邻的苯环形成共轭体系,苯环之间相互倾斜排列,在相变过程中羰基与苯环的共平面作用逐渐被打破,且在相变点苯环间的二面角明显增大.  相似文献   

3.
张新民 《合成化学》2000,8(6):519-524
合成了一种新的聚合物聚L-谷氨酸-5-(6′-己二醇肉桂酸酯基),研究了它在空气/水界面的行为,形成LB膜能力,液晶性质及光交联反应。  相似文献   

4.
含光功能基团聚合物LB膜的研究进展   总被引:4,自引:0,他引:4  
徐志康  徐又一 《高分子通报》1995,(2):112-116,98
本文在简要介绍含光功能基团聚合物LB膜之后,详细回顾了功能化LB膜体系光物理过程的研究,总结了含非线性光学基团聚合物LB膜的研究现状。最后,简要介绍了它们的应用前景。  相似文献   

5.
郭宁  王玮 《应用化学》1994,11(4):25-30
采用变温红外光谱研究了层结构标题配合物的固。固相变机理;相变主要与烷烃链和-NH_3极性端基结构变化有关,主要来源于烷烃链的堆积结构和构象的有序。无序变化,同时伴有N-H…Cl氢键强度的降低,由于在高温烃链产生GTG+GTG'和临近端基的TG构象以及GG链段,链大量扭曲,形成了烷烃链的“熔化”态,发现同相和异相C-C伸缩振动频率对烷烃“链熔化”相变很敏感,可用于表征烷烃链的链长变化。  相似文献   

6.
新型不对称四硫代富瓦烯导电LB膜的研究李洪启姚钟麒刘丹谭干祖俞贤达(中国科学院兰州化学物理研究所730000)Langmuir-Blodget(LB)技术已成为制备分子厚度的有序导电薄膜的有力工具,该领域中四硫代富瓦烯(TTF)衍生物是导电LB膜的研...  相似文献   

7.
利用3-氨基丙酸(β-ala)和过渡金属氯化物构筑了2例互为异质同晶的配位聚合物[MCl2(β-ala)]n(M=Co2+(1),Ni2+(2)),并通过差示扫描量热法、变温X射线单晶衍射以及变温介电测试研究了它们的结构相变。配合物1和2的结构中,相邻的M2+离子通过2个氯离子和1个双齿羧基的桥联作用形成一维配位链。在升/降温过程中,1和2分别在236、224 K和309、302 K附近发生高温相(Pnam)与低温相(Pna21)之间的温致结构相变;该相变主要是由配体的铵乙基由高温相中的两重无序状态冻结为低温相中的有序状态而引起的,该有序-无序型相变使这两个化合物在相变温度附近都表现出介电台阶及介电弛豫的共存现象。  相似文献   

8.
5,10,15,20-四(对-山嵛酸乙酯-α-氧代苯基)卟啉LB膜结构研究王海水,曾广赋,谷淑珍,席时权(中国科学院长春应用化学研究所长春130022)利用LB膜技术将分子组装成有序的分子单层或多层体系,研究膜内分子间相互作用和分子的结构,对了解结构...  相似文献   

9.
用红外光谱、紫外可见光谱、循环伏安法等研究了三.(2,4-二特戊基苯氧基)-8-喹淋氧基酞菁铜(简称酞菁铜)和2-十八烷基-7,7,8,8-四氰二甲基苯醌(简称C18-TCNQ)在Lang-muir-Blodgett(LB)膜中的电荷转移。实验结果表明,在交替和混合LB膜中,酞菁铜和C18-TC-NQ分子之间均发生了电荷转移,其中酞菁铜为给体分子,TCNQ为受体分子。在混合LB膜中,电荷转移程度较大。电导率测量表明荷移反应使LB膜的电导率较纯酞菁铜LB膜提高了3个数量级。  相似文献   

10.
顺丁橡胶/酯—醚液晶复合膜的富氧性能研究   总被引:2,自引:0,他引:2  
首次制成顺丁橡胶(PB)与具有二重液晶相转变(近晶相,向列相)的液晶化合物双4-(4′-乙氧基苯甲酰氧基)苯甲酸-缩乙二醇酯(DEBEB)的复合膜并研究了其富氧性能,PB/DEBEB复合膜的液晶含量10%时,室温下具有基质聚合物PB膜大几倍的氧透过系数。透过系数与温度的关系曲线呈现“N”型特征,这些现象与液晶的二重相变行为和膜的形态结构有关。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

13.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

14.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

15.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

16.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

17.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

18.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

19.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

20.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

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