一种基于2, 2'-二吡啶胺功能化的新型空间位阻型9, 9'-二芳基芴的设计、合成及其光电性质研究

用2-溴吡啶通过乌尔曼反应修饰9-(4-苯胺基)-9-苯基芴合成了一种具有大体积空间位阻的双极性分子(PFPhDPy),这种化合物因其大的空间位阻、芴优异的双极型传输特性、共轭阻断结构以及吸电子的吡啶官能团而有望获得良好的热稳定性、稳定的无定形态、高的三线态能级和良好的双极性特征.热重分析曲线表明其失重5%的分解温度为336℃.差示扫描量热曲线显示将该化合物加热到190℃既没有熔化现象也没有结晶现象,意味着该化合物具有高的形貌稳定性.通过密度泛函理论计算,该化合物的最高占有轨道(HOMO)和最低未占有轨道(LUMO)完全分离,说明该化合物具有双极性特征,通过磷光光谱得到三线态能级为3.0 eV.紫外光谱显示该化合物不依赖于溶剂效应的三个特征吸收峰分别为276、298和308 nm.荧光光谱在二氯甲烷、乙酸乙酯、乙醇和乙腈溶剂中随着溶剂的极性增加光谱发生蓝移,其最大发射峰从390 nm转变为363 nm.另外,该化合物的结构分别通过基质辅助激光解析电离飞行时间质谱(MALDI-TOF MS)、氢核磁共振(¹H NMR)和碳核磁共振(¹³C NMR)谱进行了结构表征.

A Novel Molecule Based on 2, 2'-Dipyridylamine Functionalized 9, 9-Diarylfluorene with Steric Hindance: Design,Synthesis and Electro-Optical Property Research

The bipolar molecule N-(4-(9-phenyl-fluoren-9-yl)phenyl)-2, 2'-bipydylamine (PFPhDPy) with bulky steric hindrance was synthesized successfully by substituting 9-(4-anilino)-9-phenyl-fluorene with 2-bromopyridine via Ullmann reaction, which is expected to possess good thermal stability, stable morphology, high triplet energy (E_T), and good bipolar characteristics because of the bulky steric hindrance, excellent bipolar transporting characteristics of fluorene, interrupted conjugation, andelectrondeficient pyridine group. Thermo gravimetric analysis (TGA) indicates a decomposition transition temperature of 336℃ with 5% weight loss. Differential scanning calorimetry (DSC) curve reveals no crystallization and melting phenomena by heating to 190℃, which indicates the high morphological stability of the compound. The separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), calculated by density functional theory (DFT), indicates that a bipolar molecule was obtained and high triplet energy (E_T, 3.0 eV) was calculated from the phosphorescence spectrum. The UV-Vis spectrum is independent of solvent effects with three absorption peaks at about 276, 298, and 308 nm, respectively. The fluorescence emission spectra show blue shift as the solvents' polarity increasing with emission peaks from 390 to 363 nm in the solvents of dichloromethane, ethyl acetate, ethanol, and acetonitrile. In addition, the structure of the compound was characterized by matrix-assisted laser desorption ionization time of flight mass spectrometer (MALDI-TOF MS), hydrogen nuclear magnetic resonance (¹H NMR), and carbon nuclear magnetic resonance (¹³C NMR) spectra, respectively.