1421130-58-6Relevant articles and documents
Iron(III) bromide catalyzed bromination of 2-tert-butylpyrene and corresponding position-dependent aryl-functionalized pyrene derivatives
Feng, Xing,Hu, Jian-Yong,Tomiyasu, Hirotsugu,Tao, Zhu,Redshaw, Carl,Elsegood, Mark R. J.,Horsburgh, Lynne,Teat, Simon J.,Wei, Xian-Fu,Yamato, Takehiko
, p. 8835 - 8848 (2015/03/04)
The present work probes the bromination mechanism of 2-tert-butylpyrene (1), which regioselectively affords mono-, di-, tri- and tetra-bromopyrenes, by theoretical calculation and detailed experimental methods. The bromine atom may be directed to the K-region (positions 5- and 9-) instead of the more reactive 6- and 8-positions in the presence of iron powder. In this process, FeBr3 plays a significant role to release steric hindrance or lower the activation energy of the rearrangement. The intermediate bromopyrene derivatives were isolated and confirmed by 1H NMR spectrometry, mass spectroscopy and elemental analysis. Further evidence on substitution position originated from a series of aryl substituted pyrene derivatives, which were obtained from the corresponding bromopyrenes on reaction with 4-methoxy-phenylboronic acid by a Suzuki-Miyaura cross-coupling reaction. All position-dependent aryl-functionalized pyrene derivatives are characterized by single X-ray diffraction, 1H/13C NMR, FT-IR and MS, and offered straightforward evidence to support our conclusion. Furthermore, the photophysical properties of a series of compounds were confirmed by fluorescence and absorption, as well as by fluorescence lifetime measurements.
Pyrene-based Y-shaped solid-state blue emitters: Synthesis, characterization, and photoluminescence
Feng, Xing,Hu, Jian-Yong,Yi, Liu,Seto, Nobuyuki,Tao, Zhu,Redshaw, Carl,Elsegood, Mark R. J.,Yamato, Takehiko
, p. 2854 - 2863 (2013/02/23)
A series of pyrene-based Y-shaped blue emitters, namely, 7-tert-butyl-1,3-diarylpyrenes 4 were synthesized by the Suzuki cross-coupling reaction of 7-tert-butyl-1,3-dibromopyrene with a variety of p-substituted phenylboronic acids in good to excellent yields. These compounds were fully characterized by X-ray crystallography, UV/Vis absorption and fluorescence spectroscopy, DFT calculations, thermogravimetric analysis, and differential scanning calorimetry. Single-crystal X-ray analysis revealed that the Y-shaped arylpyrenes exhibited a low degree of π stacking owing to the steric effect of the bulky tert-butyl group in the pyrene ring at the 7-position, and thus, the intermolecular π-π interactions were effectively suppressed in the solid state. Despite the significantly twisted nonplanar structures, these molecules still displayed efficient intramolecular charge-transfer emissions with clear solvatochromic shifts on increasing solvent polarity. An intriguing fact is that all of these molecules show highly blue emissions with excellent quantum yields in the solid state. Additionally, the two compounds containing the strongest electron-accepting groups, CN (4 d) and CHO (4 f), possess high thermal stability, which, together with their excellent solid-state fluorescence efficiency, makes them promising potential blue emitters in organic light-emitting device applications. Shades of blue: Pyrene-based Y-shaped blue solid-state emitters, 7-tert-butyl-1,3-diarylpyrenes 1, were synthesized by Suzuki cross-coupling reactions in good to excellent yields. Studies on single-crystal X-ray structures and the photophysical properties of these compounds strongly suggest that they are promising blue emitters in organic light-emitting device applications. Copyright
