【作者】 李贵珍；

【导师】 赵继全； 蒲守智；

【作者基本信息】 河北工业大学 ， 应用化学， 2006， 硕士

【摘要】 二芳基乙烯类光致变色化合物具有优良的热稳定性、抗疲劳性和较快的反应时间等特性,在光存储和分子开关等光电器件应用方面备受关注。因此,设计合成了一系列新型非对称二芳基乙烯化合物,并对其光电性质进行了系统的研究。主要内容如下: 设计合成了{[1-(2-甲基-5-苯基),2-(2-甲基-5-(R-基苯基))]噻吩-3-基}全氟环戊烯(R=-对氟,邻氟,间氟,对甲基,间甲基,三氟代甲基,3-噻吩基),{[1-(2,5-二甲基),2-(2-甲基-5-(R-苯基))]噻吩-3-基}全氟环戊烯(R=-对甲氧基,对乙氧基,对氯)和{[1-(2,5-二甲基)噻吩,2-(1,2-二甲基-5-氰基)]吡咯-3-基}全氟环戊烯共11种新型非对称全氟二芳基乙烯化合物,并利用核磁波谱、红外和紫外光谱等手段对其结构进行了鉴定。其中,有4种化合物培养成单晶,进行了X-射线单晶衍射分析。 研究了二芳基乙烯化合物在溶液、非晶态PMMA薄膜及晶相中的光致变色性质。结果表明,每一种物质都具有良好的光致变色特性和较高的环化量子产率。此外,考察了部分二芳基乙烯的溶剂效应,发现溶剂极性增大,闭环态的最大吸收波长发生红移。 考察了开环和闭环反应的动力学特性。在紫外光照射下,光致变色开环异构体的闭环反应为零级反应;而在可见光的照射下,闭环异构体的开环反应为一级反应。 研究了二芳基乙烯的荧光性质,重点考察了溶剂效应和浓度效应。实验结果表明,每一种物质的开环态都具有较好的荧光,而闭环态没有或者具有较弱的荧光;随着溶剂极性的增加,最大发射波长发生红移;同样随着浓度的增加,最大发射波长也呈现红移趋势。在一定浓度范围内,随着浓度的增加,荧光强度增强;但当浓度增加到一定程度时,荧光强度逐渐减弱,直到猝灭。该物质在PMMA薄膜中的最大发射波长与溶液中最大发射波长相比,均发生不同程度的红移。 对二芳基乙烯的电化学性质进行了初步研究。由于闭环态共轭长度的增加,开环态的氧化电位高于闭环态的氧化电位。 研究了二芳基乙烯的热稳定性和抗疲劳性。杂环为噻吩基的二芳基乙烯化合物具有较好的热稳定性和抗疲劳性;杂环为吡咯基的热稳定性较差,但具有较好的抗疲劳性。更多还原

【Abstract】 Diarylethenes have so far been shown to be one of the most promising materials in realizing the development of photo-mode data storage and molecule switches having photochromic characteristics, because of their thermal stability, high fatigue resistance, and very rapid response time. Many efforts have been made to study in detail the diarylethene class, including molecular design principle, synthesis, their properties, and so on.In the present dissertation, we have designed eleven nonsymmetric molecule, 1-(2-methyl-5-phenylthiophen-3-yl)-2-(2-methyl-5-(R-phenyl)thiophene-3-yl)perfluorocyclopentene (R=-p-fluoro, m-fluoro, o-fluoro, p-methyl, m-methyl, m-trifluoromethyl, 3-thienyl) and 1-(2, 5-dimethyl)-2-[2-methyl-5-(R-phenyl)thiophene-3-yl]perfluorocyclopentene(R=-p-methoxy, p-eth -oxy, p-chloro), and characterized by NMR, IR, UV-Vis spectra, et al. Four single crystal samples of the diarylethenes were prepared and analyzed by X-ray crystallography.Their optoelectronic properties, such as UV-Vis spectra, fluorescence spectra, thermal irreversibility, fatigue resistance and electrochemical properties were investigated in solution, crystalline state, and on PMMA films. They all showed good photochromic properties and gave strong fluorescence. Both the maximum emission and absorption wavelength of the diarylethenes in PMMA were longer than that of them in solutions. In addition, solvent effect and photochemical reaction kinetics of diarylethenes were also investigated. Diarylethenes showed positive solvent effect which the maximum wavelength is increased with the enhance of solvent polarity. When the intensity of the irradiation light is constant, the cyclization and cyclorevsion reaction belonged to zero and first order reaction, respectively. When the aryl groups are thiophene rings, which have low aromatic stabilization energies, the closed-ring isomers are thermally stable and can not return to the open-ring form isomers. Their fatigue resistance can be measured by irradiation with UV and Vis light by turns. The results showed that they have good fatigue resistance. Finally, the electrochemical properties of diarylethene were investigated in acetonitrile. It was found that the oxidation potentials of opening-ring state are all higher than those of closed-ring state because of the extent of π-conjugation in the closed-ring isomers.更多还原