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氮杂两性PAH衍生物的合成及其物性

Synthesis and Properties of Nitrogen-Doped Polycyclic Aromatic Hydrocarbon Amphiphiles

【作者】 张扬

【导师】 金武松;

【作者基本信息】 东华大学 , 有机化学, 2011, 硕士

【摘要】 六苯并蔻(HBC)是多环芳香族化合物的代表,由13个苯环稠合而成,具有良好的π-π堆积效应,易通过自组装形成各种具有新奇的光、电、磁等功能和特性的新型材料,在生产和生活的许多领域扮演了重要角色。通过在PAH分子骨架中引入电负性强,而原子半径与碳原子相近的氮等杂原子,可以在不改变其立体几何形状等结构的情况下,改变其理化性质,使其展现出完全不同的应用前景。本文分为两个部分:第一部分以5-溴-2-碘嘧啶为起始原料,设计并合成得到了三种两性氮杂PAH的关环前驱体13、22和26,并对它们的氧化关环条件进行了摸索。在使用36当量的FeCl3作为氧化剂,反应4个小时,我们成功的通过氧化22得到一种新型的两性氮杂PAH 2。而13在氧化反应过程中得到了一种与13的分子量相差为10的物质,但因为该物质溶解度很差,无法通过核磁等手段确认其结构。而26在使用FeCl3为氧化剂时完全不反应。这两种化合物的氧化关环条件还需要进一步摸索。第二部分对已得到的两性氮杂PAH的物性及自组装性能进行了研究,测定了化合物的红外吸收光谱、紫外吸收光谱、热重曲线以及荧光性质,并对其在多种溶剂条件下的自组装性能进行了探索,从这些数据中可以得出,该化合物具有较好的热稳定性,其自组装体主要以球体存在。在二氯甲烷和四氢呋喃溶液中,荧光颜色为金黄色,而在甲苯溶液中为黄绿色,化合物的荧光可以被酸(如三氟乙酸)淬灭。紫外和荧光谱图显示没有分裂的宽峰,这说明在溶液中化合物2并不是以单分子形式存在,而是以动态聚集体形式存在。

【Abstract】 Hexa-peni-hexabenzocoronene (HBC) consisting of 13 fused benzene rings is a one of representative compounds of the polycyclic aromatic hydrocarbon (PAH). The strong tendency to stack throughπ-πintermolecular interactions of PAHs make it easily self-assemble to form columnar structures, which can be utilized to fabricate nano soft materials with novel optical, electronic or magnetic features. Thus, the PAH derivatives plays a crucial role and occupied an important position in material science. Modificating molecular skeleton of PAH by incorporation with strong electronegativity and small atomic radius heteroatoms is an efficient method to improve the physicochemical properties without changing the molecular mophorlogies greatly, which reveals an unprecedented application prospects.The thesis was devided into two sections as follow:In the first section, three kinds of precusors 13,22 and 26 of nitrogen-doped amphiphilic PAH were designed and synthesized respectively using 5-bromo-2-iodopyrimidine as starting material, and the cyclization reaction conditions of 13,22 and 26 were investigated in detail. When 36 equivalents of FeCl3 was used as oxidant, a novel amphiphilic N-doped PAH 2 was successfully synthesized by dehydrogenative cyclization of corresponding precusor 22 for 4 hrous. Whereas oxidative cyclization of corresponding precursor 13 did not give the desired product, only a by-product with lessened about 10 in molecular weight compared with 13 was obtained. However, the clearfied sturcture could not be confirmed by NMR spectroscopy due to poor solubility of by-product. On the other hand, no reaction occurred when oxidization of 26 with FeCl3 as oxidant. Thus, the oxidation conditions for cyclization of 13 and 26 should be futher explored.In the second section, both the physicochemical properties and the self-assembling behaviors of compound 2 were studied. The essential physicochemical features of 2 were characterized with IR, UV-vis, fluorescence spectrometry, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) measurements, and the self-assembling performances of 2 were investigated in different solvents and temperatures. The results revealed that compound 2 exhibiting the preferable thermostability, and the self-assemblies were formed mainly as spherical shape. Compound 2 showed a goldish-yellow fluorescence in methylene chloride or THF and yellowish-green in toluene, respectively. By adding trifluoroacetic acid (TFA), the fluorescence was gradually quenched. Both UV-vis and fluorescence spectra resulted unstructured nature of peak bands, which suggested that compound 2 didn’t exist in monomer, but in dynamic aggregats in these solutions.

  • 【网络出版投稿人】 东华大学
  • 【网络出版年期】2011年 07期
  • 【分类号】O621.3
  • 【被引频次】1
  • 【下载频次】75
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