偶氮苯双亲化合物的合成及在其DMF中的光谱特性

以4-氨基苯甲酸乙酯为原料,通过重氮化-偶合等反应,设计合成了4-（4-辛烷氧基苯偶氮）苯甲酸钾（AZO-a）和4-（4-十四烷氧基苯偶氮）苯甲酸钾（AZO-b）等偶氮苯双亲化合物,其结构经¹H NMR和FT-IR确证。采用UV-Vis考察合成产物在N, N-二甲基甲酰胺（DMF）溶剂中紫外吸收影响。      

铜离子的偶氮苯化合物探针的制备、应用及实验教学研究

以邻苯二胺为原料,在超氧化钾的氧化作用下合成了偶氮化合物--2,2′-二氨基偶氮苯,并通过紫外可见分光光度法分析2,2′-二氨基偶氮苯与铜离子的配位作用及定量关系,将合成的偶氮化合物制备成检测试纸,应用于实际水样中的铜离子检测。在实验基础上设计综合实验,实验内容按主题分为3部分:偶氮化合物的合成,偶氮化合物与铜离子配合物的组成及稳定常数的测定,铜检测试纸的制备与水样中铜离子的可视检测。实验涵盖有机化学、无机化学、分析化学的相关知识点与实验操作,适用对象为本科高年级学生。     

新型偶氮苯金属配合物的合成与性能

合成了新型偶氮苯金属配合物。分别采用光谱分析、热分析及X射线衍射测试技术对产物进行了表征和测试。结果表明,连接偶氮苯和金属配合物之间碳链的长度对该化合物的相转变和荧光特性具有特殊的影响。该系列化合物在紫外光和热作用下具有99%以上的偶氮苯顺-反异构化反应效率;具有290和560 nm这2个波段的荧光发射光谱。由其中1个金属配合物分散在聚甲基丙烯酸甲酯网络而形成的介质可作为全息信息存储材料而实现全息图像的写入和读出。     

偶氮噻吩-富勒烯星状化合物的合成与性能研究

利用2—[4—(N—乙基—N—6—羟己基)氨基苯偶氮基]—3—氰基—5—甲酰基噻吩(1)和N—甲基甘氨酸产生的亚胺叶立德与富勒烯反应，合成了含富勒烯的偶氮噻吩化合物(2)，2再与1，3，5-苯三甲酰氯进行取代反应生成了一类以苯为核心、偶氮噻吩为连接桥、三个富勒烯(C50)为电子受体端基的星状化合物3。制备了单层太阳能电池器件(ITO／化合物3／Al)，其单色光光电转换效率(IPCE)约为2．5％。     

偶氮苯高分子的光致可逆固液转变

偶氮苯化合物是一种极具吸引力以及较为常用的光响应材料,本文主要介绍偶氮苯的光响应性质以及一些偶氮苯高分子的合成方法,解析光化学反应导致偶氮苯高分子固液转变的机理,并介绍其在粘结性材料、光致动器、光致热导开关器件及非热纳米压印中的应用。     

含硝基偶氮苯侧基的丙烯酸酯类液晶聚合物的合成、结构与性能研究Ⅰ.含硝基偶氮苯侧基的丙烯酸酯液晶聚合物的合成

设计合成了溴烷基(对硝基偶氮苯基)醚■和含硝基偶氮苯的丙烯酸酯■两组化合物;用自由基聚合和化学改性两种方法合成了含硝基偶氮苯侧基的丙烯酸酯液晶聚合物,用DSC,偏光显微镜和x-射线衍射等方法表征了聚合物的相行为。     

1,4-苯并二(口恶)烷类新木脂素Eusiderin G的全合成

以没食子酸甲酯为原料,经过6步反应(总产率为24％),对 1,4-苯并二噁烷类新木脂素天然产物Eusiderin G进行了全合成。合成反应的关键步骤是在强酸性离子交换树脂催化下,分子内的醇羟基与酚羟基之间发生脱水反应,关环形成1,4-苯并二噁烷骨架化合物。该合成路线具有简便易行、产率较高、副反应少的特点,可适用于其它具有生理活性的1,4-苯二噁烷类化合物的合成。     

氨基树脂交联型聚合物的合成及其取向松弛

用双羟基偶氮（或氧化偶氮）苯化合物与对苯二甲酰氯缩聚反应合成了端羟基偶氮（或氧化偶氮）苯低聚物。将其与丁醇醚化氨基树脂进行电场极化交联反应合成交联型非线性光学聚合物。利用红外光谱和紫外可见吸收光谱分别对交联反应、电场极化取向稳定性进行了研究。     

8-5′新木脂素类化合物的合成方法研究

对羟基桂皮酸甲酯和阿魏酸甲酯分别在氧化银催化下发生自由基仿生氧化偶联反应,合成得苯并二氢呋喃环结构化合物1,1经甲基化反应得2．1和2分别在无水碳酸钾、10％氢氧化钠水溶液等不同的碱性条件下进行反应,获得了11个苯并二氢呋喃环开环产物,即8—5′新木脂素类化合物3a～9b,实现了由苯并二氢呋喃新木脂素向8—5′新木脂素的转变,也为合成芪类化合物提供了一种新方法．C-8位上的吸电子基团如酯基的影响使苯并二氢呋喃环易在碱性条件下开环形成8-5′新木脂素类化合物．所合成化合物的结构由MS,IR,^1H NMR和^13C NMR进行了表征．     

氧化偶氮苯类化合物的新法合成

报道了一种合成氧化偶氮苯类化合物的新方法,即在含有β-环糊精和氢氧化钠的水溶液中,芳香硝基化合物可被较高选择性地还原为相应的氧化偶氮苯类化合物.该方法成本低廉、操作简单且环境友好.     

New heterocyclic tetrathiafulvalene compounds with an azobenzene moiety: photomodulation of the electron-donating ability of the tetrathiafulvalene moiety

New heterocyclic TTF compounds 1a-c and 2 with an azobenzene moiety were described. The oxidation potential of 1a could be reversibly modulated by alternating UV and visible light irradiation. As a result, a molecular switch with UV/visible light as the inputs and the electrochemical signal as the output was achieved. Moreover, it was found that the influence of the azobenzene photoisomerization on the electronic property of the TTF unit became stronger with shorter spacers in compounds 1a-c.     

Nick sealing by T4 DNA ligase on a modified DNA template: tethering a functional molecule on D-threoninol

Efficient DNA nick sealing catalyzed by T4 DNA ligase was carried out on a modified DNA template in which an intercalator such as azobenzene had been introduced. The intercalator was attached to a D-threoninol linker inserted into the DNA backbone. Although the structure of the template at the point of ligation was completely different from that of native DNA, two ODNs could be connected with yields higher than 90% in most cases. A systematic study of sequence dependence demonstrated that the ligation efficiency varied greatly with the base pairs adjacent to the azobenzene moiety. Interestingly, when the introduced azobenzene was photoisomerized to the cis form on subjection to UV light (320-380 nm), the rates of ligation were greatly accelerated for all sequences investigated. These unexpected ligations might provide a new approach for the introduction of functional molecules into long DNA strands in cases in which direct PCR cannot be used because of blockage of DNA synthesis by the introduced functional molecule. The biological significance of this unexpected enzymatic action is also discussed on the basis of kinetic analysis.     

Sulfur and Azobenzenes,a Profitable Liaison: Straightforward Synthesis of Photoswitchable Thioglycosides with Tunable Properties

Azobenzene photoswitches are valuable tools for controlling properties of molecular systems with light. We have been investigating azobenzene glycoconjugates to probe carbohydrate-protein interactions and to design glycoazobenzene macrocycles with chiroptical and physicochemical properties modulated by light irradiation. To date, direct conjugation of glycosides to azobenzenes was performed by reactions providing target compounds in limited yields. We therefore sought a more effective and reliable coupling method. In this paper, we report on a straightforward thioarylation of azobenzene derivatives with glycosyl thiols as well as other thiols, thereby increasing the scope of azobenzene conjugation. Even challenging unsymmetrical conjugates can be achieved in good yields via sequential or one-pot procedures. Importantly, red-shifted azoswitches, which are addressed with visible light, were easily functionalized. Additionally, by oxidation of the sulfide bridge to the respective sulfones, both the photochromic and the thermal relaxation properties of the core azobenzene can be tuned. Utilizing this option, we realized orthogonal three-state photoswitching in mixtures containing two distinct azobenzene thioglycosides.     

甲基橙制备实验的衍生与探索

Preparation of methyl orange is regarded as a classical basic experiment in organic chemistry. Based on the derivation of methyl orange preparation, we design a mini comprehensive experiment by combining the synthetic experiment of azobenzene compounds with spectral analysis to achieve the multi-disciplinary interactions. It not only can guide students to further understand properties of azobenzene compounds, but also can help to improve the synthetic operation skills of solid organic compounds and master the spectral analysis methods. In the meantime, we hope to break the limitation of basic experimental training and make it easier for students to cultivate scientific thinking methods.     

Influence of helical twisting power on the photoswitching behavior of chiral azobenzene compounds: applications to high-performance switching devices

Five photochromic chiral azobenzene compounds and one nonphotochromic chiral compound were synthesized and characterized by IR, 1H NMR spectroscopy, and elemental analysis. Cholesteric liquid crystalline phases were induced by mixing of the nonphotochromic chiral compound and one of the photochromic chiral azobenzene compounds in a host nematic liquid crystal (E44). The helical pitch of the induced cholesteric phase was determined by Cano's wedge method and the helical twisting power (HTP) of each sample was thus determined. The helical twisting powers of azobenzene compounds were decreased upon UV irradiation, due to trans-->cis photoisomerization of azobenzene molecules. Among the azobenzene compounds synthesized in our study, Azo-5, with isomannide (radical) as chiral photochromic dopant, showed the highest HTP and contrast ratio (Tmax/Tmin). Photoswitching between compensated nematic phase and cholesteric phase was achieved through reversible trans<-->cis photoisomerization of the chiral azobenzene molecules through irradiation with UV and visible light, respectively. Transmission rates (contrast ratios) increased with decreasing helical pitch length in the induced cholesteric phase. The influence of helical twisting power on the photoswitching behavior of chiral azobenzene compounds is discussed in detail.     

Controlled Sol–Gel Transitions of a Thermoresponsive Polymer in a Photoswitchable Azobenzene Ionic Liquid as a Molecular Trigger

Producing ionic liquids (ILs) that function as molecular trigger for macroscopic change is a challenging issue. Photoisomerization of an azobenzene IL at the molecular level evokes a macroscopic response (light‐controlled mechanical sol–gel transitions) for ABA triblock copolymer solutions. The A endblocks, poly(2‐phenylethyl methacrylate), show a lower critical solution temperature in the IL mixture containing azobenzene, while the B midblock, poly(methyl methacrylate), is compatible with the mixture. In a concentrated polymer solution, different gelation temperatures were observed in it under dark and UV conditions. Light‐controlled sol–gel transitions were achieved by a photoresponsive solubility change of the A endblocks upon photoisomerization of the azobenzene IL. Therefore, an azobenzene IL as a molecular switch can tune the self‐assembly of a thermoresponsive polymer, leading to macroscopic light‐controlled sol–gel transitions.     

偶氮苯功能化的光响应共价有机框架材料

通过后修饰的方法, 在共价有机框架(COFs)材料JUC-500的孔道中引入光敏性的偶氮苯小分子, 合成了具有光热刺激响应的共价有机框架材料JUC-501. 在紫外线和加热作用下, 孔道中的偶氮苯会发生可逆的顺-反异构变化, 对染料污染物甲基橙(MO)表现出优异的可逆吸附与释放性能.     

Photoviscosity Effect of Polymer Solutions

Poly(methyl methacrylate) and poly(methacrylic acid) having spirobenzopyran in the side groups and polyamide having azobenzene in the main chain were synthesized in attempting to construct photoresponsive polymer systems, the conformation of which can be photoregulated. The solution viscosity in benzene of poly(methyl methacrylate) containing spirobenzopyran groups (9 mole% in base unit) during irradiation was found to be 12% lower than the viscosity in the dark. The viscosity is restored to the initial value in less than 3 min in the dark after cutting off the light. A study of the solvent effect and a spectroscopic study have verified that the photoviscosity effect is due to the self-solvation of the ester side groups to the photo-produced merocyanines. Photoregulation of the polymer conformation was also achieved in methanol for poly(methacrylic acid) having spirobenzopyran and in dimethylacetamide for a polyamide having azobenzene in the main chain.     

Optical behaviour of photoimageable cholesteric liquid crystal cells with various novel chiral compounds

In theory, both polarity and steric hindrance are basic factors which affect molecular interactions. To investigate the optical properties and steric structures of chiral compounds having different chiral moieties which affect the wavelength of light reflection in liquid crystal (LC) cells, a series of novel chiral compounds and azobenzene derivatives were synthesized. The liquid crystalline phases of the compounds were identified using small angle X‐ray diffraction, differential scanning calorimetry and polarizing optical microscopy. Cholesteric LC cells with various synthesized chiral dopants which selectively reflect visible light were first prepared, the photochemical switching behaviour of colours was then investigated, with special reference to the change in transmittance in cholesteric LC cells containing an azobenzene derivative as a photoisomerizable guest molecule. Reversible isomerization of azobenzene molecules occurred in the cholesteric systems, resulting in a depression of T _ChI and a shift of the selectively reflected wavelength. We discuss the photochemically driven change in the helical pitch of the cholesteric LCs with respect to structural effects involving the chiral moieties. Molecular interactions caused by the added dopants, reliability and stability of the photoisomerization, and UV irradiation effects on the cholesteric LC cells were also investigated. A real image was recorded through a mask on a cholesteric LC cell fabricated in this investigation.     

Optical behaviour of photoimageable cholesteric liquid crystal cells with various novel chiral compounds

In theory, both polarity and steric hindrance are basic factors which affect molecular interactions. To investigate the optical properties and steric structures of chiral compounds having different chiral moieties which affect the wavelength of light reflection in liquid crystal (LC) cells, a series of novel chiral compounds and azobenzene derivatives were synthesized. The liquid crystalline phases of the compounds were identified using small angle X-ray diffraction, differential scanning calorimetry and polarizing optical microscopy. Cholesteric LC cells with various synthesized chiral dopants which selectively reflect visible light were first prepared, the photochemical switching behaviour of colours was then investigated, with special reference to the change in transmittance in cholesteric LC cells containing an azobenzene derivative as a photoisomerizable guest molecule. Reversible isomerization of azobenzene molecules occurred in the cholesteric systems, resulting in a depression of T_ChI and a shift of the selectively reflected wavelength. We discuss the photochemically driven change in the helical pitch of the cholesteric LCs with respect to structural effects involving the chiral moieties. Molecular interactions caused by the added dopants, reliability and stability of the photoisomerization, and UV irradiation effects on the cholesteric LC cells were also investigated. A real image was recorded through a mask on a cholesteric LC cell fabricated in this investigation.