Control of the electrochemical and photophysical properties of N-substituted benzo[ghi]perylene derivatives
Control of the electrochemical and photophysical properties of N-substituted benzo[ghi]perylene derivatives
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N-取代的苯并苝衍生物的电化学和光物理性质的控制
DOI：
10.1039/c7qm00301c
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发表时间：
2017
影响因子：
7
通讯作者：
Hasobe Taku
中科院分区：
文献类型：
--
作者：
Tokuo Kokichi;Sakai Hayato;Sakanoue Tomo;Takenobu Taishi;Araki Yasuyuki;Wada Takehiko;Hasobe Taku
本文报道了一系列N-取代苯并[ghi]？（BP）衍生物的合成、电化学性质和物理化学性质。孤对电子的取向对芳香核的电子结构和能级有很大的影响。也就是说，吸电子氮原子和酰亚胺基团的引入稳定了7，8-二氮杂苯并[ghi]二萘嵌苯（DABP）和7，8-二氮杂苯并[ghi]二萘嵌苯酰亚胺（DABPIm）中的最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）的能级，因为它们平行于芳环平面取向。这与1，2-重氮-7，8-二氮杂苯并[ghi] 苝酰亚胺（TABPIm）中HOMO的下降趋势形成鲜明对比。也就是说，在TABPIm的7和8位置的氮孤对电子，其垂直于环平面（即，π-系统的一部分），诱导HOMO能级增加。这些结果成功地解释了DFT计算和符合光谱和电化学的结果。关于这些衍生物的激发态动力学，引入氮原子和/或酰亚胺单元到BP核上使得能够控制荧光和系间交叉（ISC）途径的速率常数，这显著影响相应的量子产率。荧光量子产率（ΦFL）随着氮原子的引入而降低，而随着酰亚胺单元的取代而增加。
In this work, we report the synthesis, and electrochemical and photophysical properties of a series of N-substituted benzo[ghi]perylene (BP) derivatives. The orientation of the lone-pair of electrons toward the aromatic core is expected to have a great effect on the electronic structures and energy levels. Namely, the introduction of electron-withdrawing nitrogen atoms and imide groups stabilized the energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) in 7,8-diazabenzo[ghi]perylene (DABP) and 7,8-diazabenzo[ghi]peryleneimide (DABPIm) because of the parallel orientation to the aromatic ring plane. This is in sharp contrast with the decreased trend of the HOMO in 1,2-diazonia-7,8-diazabenzo[ghi]peryleneimide (TABPIm). Namely, the nitrogen lone-pair of electrons in the 7 and 8 positions of TABPIm, which are perpendicular to the ring plane (i.e., part of π-system), induced an increased HOMO level. These results are successfully explained by DFT calculations and agree well with the spectroscopic and electrochemical results. With regard to the excited-state dynamics of these derivatives, the introduction of nitrogen atoms and/or an imide unit onto the BP core enables control of the rate constants of both the fluorescence and intersystem crossing (ISC) pathways, which significantly affects the corresponding quantum yields. The quantum yields of fluorescence (ΦFL) decreased with the introduction of nitrogen atoms, whereas an increasing trend of ΦFL was observed with substitution of an imide unit.