Graphene-like Molecules Based on Tetraphenylethene Oligomers: Synthesis, Characterization, and Applications
摘要:
Graphene-like molecules were prepared by oxidative cyclodehydrogenation of tetraphenylethene(TPE) oligomers using iron(III) chloride as the catalyst under mild conditions. All the oxidized samples can be separated effectively from the stepwise ring-closing reaction that highly related to the reaction time. For example, the model compounds obtained from the stepwise cyclization reaction show a regular red-shift in UV/vis absorption and photoluminescence (PL) spectra. This result reveals that the molecular conjugation length will extend with the stepwise ring-closing reaction going on. Interestingly, we successfully obtained a series of colorful luminogens with blue, cyan, and green emission during this stepwise and accurate ring closing process. Cyclic voltammetry measurements taken give the corresponding band gap, which supports the results obtained from optical spectroscopy. For the strong intermolecular interaction, our graphene molecules can self-assemble to form a red-colored and hexagonal fiber. Furthermore, some molecules exhibit piezochromic luminescence. The PL emission of the molecules before and after oxidation can be dramatically quenched by picric acid through the electron transfer and/or energy transfer mechanism, enabling them to function as chemosensors for explosive detection. In addition, fluorescence cell imaging studies proved their potential biological application.
在这项工作中,从1,1-双(4-苯基羰基)-2,2-二苯乙烯的McMurry偶联反应中一步合成了四苯乙烯大环,收率为45%。通过用四氯化铁(III)在硝基甲烷中氧化四苯乙烯大环,可以得到更平面的环化化合物。探索了它们的异常光学性质和电性质。测得的迁移率分别为0.7022和0.0055cm 2 V -1 s -1。分解温度也通过热重分析测得分别为342°C和455°C,表明具有良好的热稳定性。对结构和性质的理解将有利于石墨烯的化学合成。