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1.
单臂液晶冠醚LB膜的研究   总被引:4,自引:2,他引:4  
首次研究了4种单液晶冠醚(1~4)的LB膜成膜特性,实验发现它们在气-液界面均可形成单分子膜,但4的稳定性较差,3易转移到玻璃基片上形成Y型膜。4种化合物与硬脂酸以1:1混合形成稳定的Y型LB膜。小角X射线衍射证实了膜的有序结构。用CPK原子模型对成膜分子构型和面积进行了估算,其结果与实验一致。并讨论了分子结构对成膜性能的影响。  相似文献   

2.
单臂冠醚液晶LB膜的相变研究   总被引:2,自引:0,他引:2  
研究了两种单臂冠醚液晶及配合物(1, 2及1.Eu^3^+)的LB膜的成膜特性,实验发出它们均可在气-液界面形成单分子膜, 但不易转移, 化合物1在压膜过程中出现一维相变。用CPK模型对成膜分子构型和面积进行估算, 其结果与实验相一致, 并讨论了冠醚液晶结构对LB膜相变的影响。  相似文献   

3.
设计并合成了3个低温冠醚液晶-单臂脂环冠醚液晶,考察了冠醚结构与液晶性质的关系,单臂冠醚液晶分子具有液晶蛋白质应满足长径比大于3,分子具有一定的平面特性和能通过引入手性基团使单臂冠醚液晶分子产生手性近晶相等条件。  相似文献   

4.
研究了胆甾液晶二氮杂冠醚N,N′-双(胆甾-5-烯-3β-氧羰甲基)-1,10-二氮-4,7,13,16-四氧环十八烷(1)及其与Eu^3+的配合物(2),2一苯甲酸的混配物(3)的LB膜和荧光性质,结果表明:1,2和3在水溶液亚相液面形成稳定的单分子膜,但只有1的单分子面积受亚相pH的影响1,2和3的单分子膜都容易转移到石英基片上形成LB膜,其中2和3为X型,转移比分别为0.6和1.0,在LB膜  相似文献   

5.
研究了含有双臂胆甾基的氮杂冠醚化合物的单分子膜成膜特性,测试了其LB膜的吸收光谱和小角X-射线衍射谱。结果表明,这种化合物成膜性能和转移性能比单臂的胆甾基氮杂冠醚化合物好。结合CPK原子模型,推测了该分子在膜中的取向和构型。  相似文献   

6.
冠醚液晶出现至今仅十几年,由于其具有冠醚和液晶的各种性质而受到人们的关注[‘-‘1.我们在已有工作的基础上,设计合成了5种酸胺型冠醚液晶分子(4—8),其中3种分子(4-6)具有液晶性.合成路线如下:1结果与讨论合成样品4-8经IR、MS、‘HNMR和元素分析确证其结构.用DSC和Texture图测定了4-6的液晶性质,其结果见图1.化合物7、8无液晶性,分子长径比分别为5.8:I,满足一般律状向列液晶分子长径比的要求.当在其分子链中增加1个苯环(5、6)时,分子的刚性链比例增大,整个分子的刚性增加,则具有液晶性.双臂型冠醚液…  相似文献   

7.
合成并表征了一种新的非两亲性共轭桥联双二茂铁衍生物,该化合物在空气/水界面上易形成较稳定的单分子膜,与花生酸形成的混合膜易组装成LB膜,紫外-可见吸收光谱表明:LB上膜分子中发生了聚集,扫描电镜观察了混合单层LB膜的表面形貌及膜的相分离。循环伏安研究表明:混合单层LB膜修饰电极对Fe(CN)/Fe(CN)离子对的电化学反应具有良好的电催化效应,对抗坏血酸电化学氧化具有明显的促进作用。  相似文献   

8.
冠醚修饰的固体支撑双层类脂膜的形成及性能研究   总被引:3,自引:1,他引:3  
用饱和了胆固醇和饰用冠醚的角鲨烷/氯仿溶液作成膜液,制备了冠醚修饰的固体支撑双层类脂分子膜。重点考察了成膜物种及技术对膜稳定性及电特生影响。其膜电势随接触水相中的变化呈现Nernst响应,线性范围10^-4-10^-1mol/L。  相似文献   

9.
C60的LB膜和自组装膜   总被引:5,自引:0,他引:5  
制作C60分子在固体基片上的有序薄膜是研究它们优异物性和付诸于实际应用的必要环节和关键问题之一。LB技术能够把分子形状呈球形的疏水分子C60在空气-水的界面铺展成稳定的漂浮膜,并能沉积成LB膜。至于用“分子绳索”把C60固定在基片上而形成的自组装膜更具有优良的特性。本文综述和评价了纯C60、C60混合物和C60衍生物LB以及C60自组装膜的制备及其结构特征和性质;并对这方面的工作做了一定的展望。  相似文献   

10.
赵晖  张引 《分析化学》1998,26(8):981-984
用红外光谱、紫外可见光谱、循环伏安法等研究了三(2,4-二特戊苯氧基)-8-喹啉氧基酞菁铜和2-十八烷基-7,7,8,8-四氰二基苯醌在Langmuir-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,电葆转移程度较大。电导率测量表明荷移反应使LB膜的电导率较  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.
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   

13.
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   

14.
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   

15.
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   

16.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

17.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

18.
19.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.  相似文献   

20.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

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