席夫碱及其络合物的可逆热致变色材料

对具有可逆的热致变色的席夫碱及其络合物的分类、合成、变色机理以及发展前景等进行了回顾和探讨。     

聚席夫碱纳米纤维的制备与表征

4,4'-二氨基-三苯胺与对苯二甲醛在溶液中用缩聚的方法合成出聚席夫碱, 并用溶液涂膜自组装的方法制备出了纳米纤维. 用电子扫描显微镜观察到纤维为均匀分散的簇状; 拉曼、傅利叶红外表征了纳米纤维的化学结构; 通过循环伏安法测试了聚合物的氧化还原电势, 证明聚合物具有电学活性和变色丰富的电致变色性能; X射线衍射图与DSC谱表明聚合物为非晶结构, 只含有部分堆积有序结构. ESR谱图表明在常温下空气中聚合物中存在有稳定的自由基, 为空穴跳跃导电机理.     

水杨醛缩芳胺类席夫碱的光致变色性质

21世纪信息将主要以光为介质进行传输和处理,因此,需要开发出一系列的化合物或材料以用于高密度信息存储、电或光驱动的显示器件、光学运算以及其它非线性光学器件.水杨醛与芳胺衍生物缩合得到的水杨醛缩芳胺类席夫碱的生物活性和光学特性与其组成、结构、取向和分子间相互作用密切相关[1-2],具有光致变色或热致变色性质,受到人们的重视[3-5].因此,本文合成3种非两亲性的水杨醛席夫碱N-(对苯甲酸)-2-羟基苯甲亚胺(简称S1)、N-(对苯甲酸)-2-羟基-5-硝基苯甲亚胺(简称S2)和N-(对苯甲酸)-2-羟基-5-氯苯甲亚胺(简称S3),用紫外-可见光谱分别对其在不同溶剂中进行了光谱性质的研究,结果表明3种水杨醛缩芳胺席夫碱在不同溶剂中均具有光致变色性,其固态具有热致变色性,对光的宏观响应速度较快,为可能实用化提供了参考.     

可溶性共轭聚席夫碱的合成、表征及电性能

本文以对苯二胺分别与乙二醛、丁二酮、３，４－己二酮和４，５－辛二酮缩聚合成了四种主链结构相同而侧基各异的新颖共轭性聚席夫碱．采用红外光谱和元素分析等方法对聚合物进行了表征．发现带有侧烷基的共轭性聚席夫碱能溶于一般有机溶剂；不同侧基的聚席夫碱溶解性是：两基聚席夫碱＞乙基聚席夫碱＞甲基聚度夫碱．测定了四种共轭聚席夫碱的本征导电率及其与温度的关系，结果表明，聚合物具有半导体性质．当聚合物以碘掺杂后，导电率可从１０－１１－１０－１２Ｓ／ｃｍ增加到１０－３－１０－４Ｓ／ｃｍ．探讨了共轭聚合物的侧基取代对掺杂后导电性的影响．     

聚氯乙烯负载席夫碱树脂的合成及其对金属离子的吸附

聚氯乙烯负载席夫碱树脂的合成及其对金属离子的吸附刘理中，俞善信，肖立新（湖南师范大学化学系长沙４１００８１）（中南工业大学冶金化学研究所长沙）关键词聚氯乙烯，负载树脂．席夫碱，金属离子，吸附高分子负载席夫碱可用于离子吸附和催化等领域，汪信［１，２］等...     

双分子膜上染料的吸附性质及对膜结构的影响

系统地研究了染料甲基橙和达旦黄在含席夫碱基囊泡双分子膜阳离子表面上的吸附和聚集，以及由此产生的对膜聚集结构的影响，染料的吸附和聚集可经电子吸收光谱的因吸附产生的沉淀证实，并且ＭＯ的聚集结构的Ｈ－聚集，ＴＹ的聚集结构为Ｊ－聚集。改变ｐＨ的研究表明ＭＯ在变色ｐＨ值以及因形成阳离子而解聚，ＴＹ在酸性条件下亦因离子化程度减弱和部分质子化而使聚集被削弱，但在碱性条件下其聚集产生更大的红移。温度变化的结果显示     

噻吩-2-甲醛缩L-半胱氨酸席夫碱的合成、晶体结构及量子化学研究

采用噻吩-2-甲醛分别与邻氨基苯硫酚和硫代氨基脲合成了2种噻吩-2-甲醛杂环席夫碱.利用红外光谱、紫外-可见光谱、荧光光谱、X-射线单晶衍射分析、热重分析和核磁共振氢谱等检测方法对2种目标新型杂环类席夫碱产物的结构和性质进行了表征与分析.采用量子化学中常用的密度泛函方法(DFT)对2种新席夫碱化合物进行几何优化,采用单激发组态相互作用(CIS)和含时密度泛函方法(TD-DFT)进一步优化,比较计算光谱与实际测试光谱之间的误差,探究了2种席夫碱化合物荧光发光机制,为这类席夫碱分子结构设计提供了理论依据.     

氨基酸席夫碱配合物的制备及性能研究进展

研究表明，某些含有-N=CH-基团的有机化合物具有一定的抗癌作用，它与某些金属生成配合物后效果更加显著。氨基酸是组成酶和蛋白质的基本单元，与含活泼羰基的化合物形成含有多个强电负性配位原子的席夫碱，此类席夫碱具有较强的配位能力和多样的配位模式的优点，研究其与金属离子配位所形成配合物可以为研究抗肿瘤、抗癌药物提供信息。80年代以来，有不少关于研究过渡金属离子与氨基酸席夫碱配合物的合成和性质的报道，并进行了大量生物生理活性的研究旧剖。本文综述了近年来国内外有关氨基酸席夫碱配合物的制备及其性能应用。     

含NS和NNSS供电子原子的钌(Ⅱ)羰基配合物

通过[RuHCl(CO)(PPh₃)₂(B)] (B=PPh₃, 吡啶 (py), 哌啶 (pip), 吗啉 (morph))与适当的席夫碱按1∶1的物质的量的比反应，合成了二齿和四齿席夫碱钌(Ⅱ)配合物。所用席夫碱配体通过S-苄基二硫代肼基甲酸酯与2,3-丁二酮(物质的量的比分别为1∶1和1∶2)的缩合反应制得。通过元素分析和多种物理化学方法对钌(Ⅱ)配合物和其席夫碱配体进行了表征。钌(Ⅱ)配合物为六配位的反磁性物质。用三种细菌对席夫碱配体及其钌(Ⅱ)配合物的抗微生物活性进行了筛选试验。     

4-氟苯甲醛丙氨酸席夫碱的合成及其IR和Raman光谱分析

席夫碱及其金属配合物具有杀菌、抗菌、植物生长调节等生理活性,在医药、农药等领域有广泛的应用前景[1-2].含氟席夫碱及其配合物具有独特的生物活性, 在医药研究中备受关注[3-4]; 氨基酸席夫碱一直是人们感兴趣的研究课题,但对含氟的氨基酸席夫碱的研究未见报道.本文报道了4-氟苯甲醛与丙氨酸形成的席夫碱的合成方法及利用1H NMR、红外光谱、拉曼光谱、热重分析等测试手段进行表征的结果,化合物的生物活性研究正在进行.     

Tuning the optical properties of fluorinated indolylfulgimides

Photochromic fluorinated indolylfulgides have been identified as potential candidates for a wide range of applications including optical switches, photoregulators of biological processes, and optical memory media. In humid environments or biological systems, hydrolytic stability is essential. In an effort to improve hydrolytic stability, a series of indolylfulgimides has been synthesized from a parent trifluoromethyl-substituted indolylfulgide. The nitrogen of the succinimide moiety is linked to either a dimethyl amino or one of seven substituted phenyl groups. The phenyl groups feature substituents with increasing electron-withdrawing ability. The spectral characteristics of each compound have been examined, revealing that the wavelength absorption maxima of each form increases with increasing electron-withdrawing ability of the substituted N-phenyl ring. The quantum yields of the photoreactions have been determined with the N-(phenyl)fulgimide showing a ring closure value of nearly 0.30 in toluene. In addition, the hydrolytic, thermal, and photochemical stabilities of each compound have been measured. The fulgimides exhibit at least a 200-fold enhancement of hydrolytic stability for the Z-form and over a 1000-fold enhancement for the C-form in comparison to the same form of the parent fulgide. The N-(2,3,5,6-tetrafluoro-4-trifluoromethylphenyl)fulgimide can undergo up to 3000 photochemical cycles (coloration followed by bleaching) before losing 20% of its initial absorbance at photostationary state.     

Potentiometric discrimination of neutral forms of nitrophenol isomers by liquid membrane electrodes incorporated with corroles

The results of studies on the use of corrole derivatives as a host ligand in the PVC liquid membrane electrodes and their ability for the potentiometric high-throughput discrimination of nitrophenol guests have been presented. The significance of parameters which govern the mechanism of generation of potentiometric signals such as the attachment of substituents in the corrole structure, acidity and lipophilicity of the guests, and pH of the aqueous solutions has been discussed in details. Supramolecular recognition processes between corroles and para-nitrophenol molecules have been confirmed by independent NMR measurements.     

C- and N-Substituted Phosphorus(III) Derivatives of Azomethines

Abstract

The reactions of halogenides of P(III) acids with lithium derivatives of azomethines depending on the substituents at the phosphorus atom, the structure of azomethines and conditions of the reaction were studied. A method for synthesizing tile C- and N-phorphorus(III) substituted azomethines was proposed:     

A comparative PMR study of exchange reactions in some substituted N-methylbenzenesulphonamides and their N-phenylmercury derivatives

Proton---proton, metal---metal and metal---proton exchange type reactions have been studied for a number of substituted _N-methylbenzenesulphonamides and their N-phenylmercury derivatives through the use of a PMR technique. It has been found that metal---metal type exchange processes proceed more readily than proton---proton processes in some cases. The presence of substituents in the aromatic ring of the benzenesulphonamide moiety has been shown to affect the rate of the metal---metal exchange process to a smaller extent than that of hydrogen exchange. It has been demonstrated that transfer from a chlorobenzene to a pyridine solution accelerates exchange in N-methylbenzenesulphonamides but retards exchange in their phenylmercury derivatives, whereas intramolecular coordination inhibits exchanges in both types of compound. The differences in the influence of substituents and solvents upon the rates of the metal---metal and proton---proton exchange processes are discussed in terms of the ease of formation of a transition state in such exchange reactions.     

Direct atomic force microscopy observation of DNA tile crystal growth at the single-molecule level

While the theoretical implications of models of DNA tile self-assembly have been extensively researched and such models have been used to design DNA tile systems for use in experiments, there has been little research testing the fundamental assumptions of those models. In this paper, we use direct observation of individual tile attachments and detachments of two DNA tile systems on a mica surface imaged with an atomic force microscope (AFM) to compile statistics of tile attachments and detachments. We show that these statistics fit the widely used kinetic Tile Assembly Model and demonstrate AFM movies as a viable technique for directly investigating DNA tile systems during growth rather than after assembly.     

Synthesis of 2,2'-Quinocyanines with Long N-Alkyl Substituents

2,2'-Quinocyanines with long alkyl substituents on one or both nitrogen atoms have been synthesized. ¹H NMR spectroscopy has been used to study the processes occurring during the alkylation of the starting quinoline bases.     

The mass spectra of substituted 2-methylbenzophenones

The mass spectra of some methoxy and methyl derivatives of 2-methylbenzophenone have been examined. Loss of a substituents from 3′-and 4′-positions as well as the previously known loss from 2′-positions are important fragmentation processes. Thus, these fragmentations are of little use in locating substituents on benzophenones of unknown structure. Deuterium labelling shows the [M - 1]⁺ ion from 3′,4,4′,5,5′-pentamethoxy-2-methyl benzophenone to be due largely to loss of hydrogen from 2′- and 6′-positions.     

The azido-tetrazole equilibrium in the thiazolo[2,3-e]tetrazole series

Thiazolo[2, 3-e]tetrazole and its derivatives with electropositive and electronegative substituents have been synthesized. The bromination, thiocyanation, and nitration reactions of some thiazolo[2,3-e]tetrazoles have been studied. By means of the IR spectra, the structure of the compounds synthesized in the crystalline state and in solutions has been determined. The influence of substituents and the polarity of solvents on the position of the azido-tetrazole equilibrium in the thiazolo[2, 3-e]tetrazole series has been studied.     

Effects of Substituents on Metastable‐State Photoacids: Design,Synthesis, and Evaluation of their Photochemical Properties

Recently, metastable‐state photoacids have been widely used to control proton transfer in numerous chemical and biological processes as well as applications with visible light. Generally, substituents have a great influence on the photochemical properties of molecules, which will further affect their applications. Yet, the effects of substituents on metastable‐state photoacids have not been studied systematically. In this work, 16 metastable‐state photoacid derivatives were designed and synthesized on the basis of substituents having a large range of σ–π electron–donor–acceptor capabilities. The effects of substituents on the color display [or maximum absorption band(s)], solubility, pK_a values, dark/photoacidity, photosensitivity, and relaxation kinetic(s) were investigated in detail. This study will be helpful for the targeted design and synthesis of promising photoacids and the application of their photocontrolled proton‐release processes in functional materials/devices.