【作者】 李刚；

【导师】 宁桂玲； 贡卫涛；

【作者基本信息】 大连理工大学 ， 功能材料化学与化工， 2013， 博士

【摘要】 吡啶盐是一类重要的六元氮杂环有机芳香盐类化合物,在化学、材料及生物学领域具有广泛的应用前景。优异的光物理化学性能使其可以用作非线性光学材料、荧光材料、光敏材料、光引发剂等：而离子结构特性使其可以用作相转移催化剂、阳离子表面活性剂、离子液体等。近年来,吡啶盐在基因传送及超分子化学领域表现出的优异性能为其研究注入了新鲜活力。因此设计合成新型吡啶盐并研究其功能具有重要的理论意义和应用价值。在吡啶盐的几种合成方法中,吡喃盐与伯胺反应合成吡啶盐具有反应条件温和、产物易分离、产率高等优点,但到目前为止利用该方法合成口-单取代毗啶盐却未见报道。由于吡啶盐的性能与吡啶环上取代基的种类和位置有关,而a-单取代吡喃盐因其α-H的高反应活性,可能衍生出一系列新型吡啶盐,进而获得新性能。本课题组在前期工作中发现了由多取代环戊二烯合成α-单取代吡喃盐的新方法,可以得到不同结构的a-单取代吡喃盐,如2,4,5-三苯基吡喃盐和2,3,4,5-四苯基吡喃盐,研究表明这些a-单取代吡喃盐在一定条件下能与伯胺进行一步反应生成相应的a-单取代吡啶盐。这不仅实现了一系列新型吡啶盐的新方法合成,也突破了a-单取代毗啶盐不能由a-单取代毗喃盐直接制取的限制。以此为基础,本论文设计合成了一系列新型α-单取代吡啶盐,讨论了合成机理并研究了其在有机合成以及超分子化学领域的应用。具体的研究内容和结果如下：(1)a-单取代吡啶盐的合成。选取带有不同取代基的伯胺与2,4,5-三苯基吡喃盐和2,3,4,5-四苯基吡喃盐进行反应,探讨了反应的普遍性,研究了溶剂和取代基对反应的影响,利用核磁、质谱、红外、元素分析及单晶衍射等表征手段确定了产物结构。结果表明：a-单取代吡啶盐可以由a-单取代吡喃盐直接制取,吡喃环苯基取代基数量是反应能否发生的决定因素之一；(2)α-单取代吡啶盐的光环化反应。利用吡啶盐的光环化反应合成出菲啶盐类化合物,考察取代基对反应的影响,研究了菲啶盐的光谱性质和自组装性能。结果表明：当吡啶盐上带有强供电子基团时光环化反应不能发生；菲啶盐具有较好的荧光性质；在不同条件下菲啶盐可以形成具有不同形貌的微纳米结构；(3)α-单取代吡啶盐的阴离子识别研究。考察了带有氨基取代基的吡啶盐及具有钳形结构双吡啶盐在阴离子识别方面的应用,利用荧光、紫外光谱、核磁滴定及单晶表征研究了识别过程和识别机理。结果表明：1-(2-氨基苯)-2,4,5-三苯基吡啶盐是一种F-反应识别剂,具有很高的选择性,利用吡啶盐在F-作用下发生分子内环化反应生成1,3,4-三苯基吡啶[1,2-a]苯并咪唑实现对F-识别；1,1’-(1,3-亚苯基)-双-2,4,5-三苯基吡啶盐是一种NO3-识别剂,由于受体与阴离子间分子构型的匹配,利用氢键及电荷诱导效应使得双吡啶盐分子结构趋于平面化导致荧光增强从而达到识别目的；(4)α-单取代吡啶盐的分子内闭环反应研究。研究了在碱作用下(2-氨基苯)-吡啶盐发生分子内环化生成吡啶[1,2-a]苯并咪唑类化合物的反应,利用核磁、质谱和单晶衍射表征手段确定了产物的结构,讨论了溶剂、碱、反应温度、反应气氛及反应时间对反应的影响,确定了最优反应条件,并研究了这类化合物的荧光性质。结果表明：常温下,吡啶盐在氧气及碱作用下发生分子内环化反应生成吡啶[1,2-a]苯并咪唑：这类化合物具有较高荧光量子效率,硝基取代基的引入可以起到调变荧光的目的。更多还原

【Abstract】 Pyridinium salts are a type of organic aromatic compounds with six-numbered N-heterocyclic cations and have wide applications in many fields covering chemistry, biology and materials science. Pyridinium salts can be used as non-linear optical materials, fluorescence materials, photosensitive materials, photoinitiators due to their excellent photophysical and photochemical properties. On the other hand, owing to their unique ionic structures, they can also be used as phase transfer catalysts, cationic surfactants, ionic liquids. In recent years, new applications expanded to gene transfer and supramolecular chemistry bring new energy to the pyridinium research. In this case, design and synthesis new pyridinum salts are of great significance.Among several synthetic approaches for pyridinium salts, the reaction of pyrylium salts with primary amines is a predominant method due to its mild reaction condition, easy separation of production and high yield. However, there is no report about the synthesis of a-monosubstituted pyridinium salts by using this method. The properties of pyridinium salts depend on the kind and the position of substituents on pyridinium rings. Due to the a-H of a-monosubstituted pyrydinium salts, it is possible to get a series of new pyridinium salts with novel functions. In our previous research, we found a new method to synthesize a-monosubstituted pyrylium salts from polysubstituted cyclopentadienes, such as2,4,5-triphenylpyrylium salt and2,3,4,5-tetraphenylpyrylium salt. We tried the reaction of them with various primary amines. It was found surprisingly that, in our case, a-monosubstituted pyridiniums were obtained directly from their a-monosubstituted pyrylium precursors. This result also proved the previous conclusion was wrong. This paper is aimed at the synthesis of new a-unsubstituted pyridinium salts, reaction mechanism discussion and applications in synthetic chemistry and supramolecular chemistry fields. The study consists of four parts as below:(1) Synthesis of a-unsubstituted pyridinium salts. Performed the reaction of2,4,5-triphenylpyrylium salt and2,3,4,5-tetraphenyl pyrylium salt with various primary amines. A series of a-monosubstituted pyridinium salts were synthesized and carefully characterized. It was found that a-monosubstituted pyridinium salts can be obtained directly from their a-monosubstituted pyrylium precursors, the number of the phenyl gourps is one of the key roles of this reaction;(2) The photocyclization of α-unsubstituted pyridinium salts. Phenanthridinium salts were synthesized by α-unsubstituted pyridinium salts photocyclization. It was found that the reaction did not occur when pyridinium salts with strong electron-donating substituents. And the spectra indicated that phenanthridinium salts have good fluorescence properties. Meanwhile, under different conditions phenanthridinium salts can form different crystal morphologies;(3) a-unsubstituted pyridinium salts as anions sensors. Pyridinium salts with amino substituent and dipodand bipyridinium salt were studied as anions sensors, the sensing and induce-fit process were examined by fluorescence spectra, UV-vis spectra, H NMR titration and single crystal. The results show that1-(2-aminophenyl)-2,4,5-triphenylpyridinium can be served as an efficient chemodosimeter for sensing fluoride ion, an intramolecular cyclization from pyridinium3q to pyrido[1,2-a]benzimidazole7a initiated by F-.1,1-(1,3-phenylene)bis-2,4,5-triphenylpyridinium could be served as an efficent NO3-sensor. Due to the match of moleculars’ structures, hydrogen bond and the charge induction enhanced planarity of molecular5e. And the planarity of molecular induced the increasing of the fluorescence intensity;(4) Intramolecular cyclization of a-unsubstituted pyridinium salts. The intramolecular cyclizations from2-aminophenyl-pyridinium salts to pyrido[1,2-a]benzimidazole in the presence of base were studied. By studying reaction conditions, such as solvents, base, temperature, atmosphere, reaction time, the best reaction condition was confirmed. A series of pyrido[1,2-α]benzimidazoles were synthesized and carefully characterized. And the fluorescence spectra indicated that this kind of compounds with high quantum yield could be served as good fluorescence materials. The nitro substituent can modulate the fluorescence.更多还原