Nitrogen-rich pi-conjugated stars - discotic liquid crystals with an electron deficient core

将合成具有宽中间相、高电子亲和、高效荧光和传感能力的新型盘状液晶。缺电子杂环、吡嗪、1,3,5-三嗪、1,2,4-三唑和1,3,4-恶二唑是这些星形或圆盘状分子中心的组成部分。一系列的烷基链以醚、胺或硫醚的形式附着在星形的边缘，以提供溶解度和熔融性。链条的数量、位置、类型和长度是调节热性能的工具；pi-片段的聚集产生柱，它们的脂肪族表面应该导致广泛的中间相。N、O、S是中等到强给电子基团，从而改变了光学性质。研究了相、浓度、极性和质子对光谱和非线性光学性质的影响。热方法将用于表征相行为，x射线衍射来阐明lc相的结构。作为oled中潜在的新型n型半导体和发射体，将进行电学研究。一些恒星将成为反应的底物，将芳烯碎片转化为环杂环体系。Cadogan反应将邻硝基二芳基单元还原为杂类咔唑，1,2-二芳基芳烃在Scholl反应中被氧化，氧化光环作用将相邻的二芳基芳烃转化为扩展凝聚的杂环芳烃体系。s-七嗪是一种独特的荧光团，将作为一种新的hekates核心。

New discotic liquid crystals displaying broad mesophases, high electron affinity, efficient fluorescence and sensing ability will be synthesized. Electron deficient heterocycles, pyrazine, 1,3,5-triazine, 1,2,4-triazole and 1,3,4-oxadiazole are building blocks for the center of these star- or disc-shaped molecules. A series of alkyl chains is attached as ether, amine or thioether to the rim of the stars to provide solubility and fusibility. Number, position, type and length of the chains are tools to tune the thermal properties; aggregation of pi-segments yields columns and their aliphatic surface should result in broad mesophases. N,O,S are moderate to strong electron donating groups, thus modifying the optical properties. The impact of phase, concentration, polarity and protons on optical spectra as well as non-linear optical properties will be studied. Thermal methods will be used to characterize phase behavior, X-ray diffraction to elucidate structures of the LC-phases. As potential new n-type semiconductors and emitters in OLEDs, electrical studies will be performed. Some stars will be substrates for reactions converting arylene fragments to annulated heterocyclic systems. Cadogan reaction reduces o-nitrobiaryl units to heteroanalogous carbazoles, 1,2-diarylarenes will be oxidized in a Scholl reaction and oxidative photocyclisation transforms vicinal distyrylarenes to extended condensed heterocyclic aromatic systems. s-Heptazine, a unique fluorophore, will be introduced as a new core for hekates.