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.
Aggregation Emission Properties of Oligomers Based on Tetraphenylethylene
摘要:
A series of eight derivatives based on tetraphenylethylene were prepared, and two of these, i.e., 1,1-bis(4-phenylcarbony1)-2,2-diphenylethylene (2), 1,1,2,2-tetrakis(4-phenylcarbonyl)phenylethylene (4), were characterized crystallographically. Because the rigidity and steric hindrance in the molecular structure enhanced regularly from sample 5 to 8, UV-visible absorption and PL spectra of 5-8 show the transition from aggregation-induced emission (AIE) to aggregation-induced emission enhancement (AIEE) behavior. Solid fluorescence lifetime characterization shows that samples with less steric hindrance and more interaction in or between molecules will result in a short fluorescence lifetime. All samples 5-8 become more emissive when their chains are induced to aggregate by adding water into their acetonitrile solutions. Cyclic voltammetry measurements taken give the band gap of sample 5-8 as 2.88, 2.70, 2.56, and 2.43 eV, and theoretical calculations also support these bad gap results. Conformational simulations also suggest that the origin of transition from AIE to AIEE behavior is due to the restricted intramolecular rotations of the aromatic rings in samples.
Synthesis and properties of a graphene-like macrocycle based on tetraphenylethene
作者:Han Wang、Tingting Lin、Ji Ma、Weizhi Wang
DOI:10.1016/j.tet.2014.06.018
日期:2014.8
this work, tetraphenylethene macrocycles are selectively synthesized in one step from McMurry coupling reaction of 1,1-bis(4-phenylcarbonyl)-2,2-diphenylethene in 45% overall yield. A more planar cyclized compound can be obtained by oxidization of tetraphenylethene macrocycles with iron (III) chloride in nitromethane. Their unusual optical properties and electrical properties are explored. The measured
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。
Aggregation Emission Properties of Oligomers Based on Tetraphenylethylene
A series of eight derivatives based on tetraphenylethylene were prepared, and two of these, i.e., 1,1-bis(4-phenylcarbony1)-2,2-diphenylethylene (2), 1,1,2,2-tetrakis(4-phenylcarbonyl)phenylethylene (4), were characterized crystallographically. Because the rigidity and steric hindrance in the molecular structure enhanced regularly from sample 5 to 8, UV-visible absorption and PL spectra of 5-8 show the transition from aggregation-induced emission (AIE) to aggregation-induced emission enhancement (AIEE) behavior. Solid fluorescence lifetime characterization shows that samples with less steric hindrance and more interaction in or between molecules will result in a short fluorescence lifetime. All samples 5-8 become more emissive when their chains are induced to aggregate by adding water into their acetonitrile solutions. Cyclic voltammetry measurements taken give the band gap of sample 5-8 as 2.88, 2.70, 2.56, and 2.43 eV, and theoretical calculations also support these bad gap results. Conformational simulations also suggest that the origin of transition from AIE to AIEE behavior is due to the restricted intramolecular rotations of the aromatic rings in samples.
Graphene-like Molecules Based on Tetraphenylethene Oligomers: Synthesis, Characterization, and Applications
作者:Ji Ma、Tingting Lin、Xiaoyong Pan、Weizhi Wang
DOI:10.1021/cm501590w
日期:2014.7.22
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.