摘要/Abstract

将多环芳烃中的碳碳双键替换成等电子体和等结构体的硼氮键是有效调节多环芳烃光物理性质的手段之一，已成为有机材料领域研究的热点.文献中报道的多是平面型的硼氮芳烃分子，非平面的硼氮芳烃研究相对较少.本工作研究了两个系列非平面的硼氮[4]螺烯分子的合成和性质，通过Suzuki偶联、亲电芳香硼化及亲核取代反应，简洁地合成了目标分子，并通过¹H NMR、¹³C NMR和¹¹B NMR等表征.单晶结构表明硼氮[4]螺烯具有螺烯的特征螺旋结构.结合理论计算对硼氮[4]螺烯的芳香性进行了定性定量分析，发现硼氮[4]螺烯的硼氮子环具有弱的芳香性.光物理研究表明，硼氮[4]螺烯相对于全碳螺烯，表现出了显著的红移吸收光谱和轻微的蓝移发射光谱，以及较高的荧光量子产率.
关键词: 芳烃, 硼氮杂环, 螺烯, 硼
Repalcement of C=C bond with an isoeletronic and isosturctural B—N bond is an effective way to tune the photophyscial properties of polycylic aromatic hydrocarbons (PAHs), which have become the hot topic in the filed of optoelectronics. There are relatively smalll number of the non-planar BN-PAHs exsited, compared to the large number of planar BN-PAHs being synthesized. In this paper, the synthesis and properties of two series of non-planar BN[4]helicenes are discribed. The synthesis is quite straightforward by sequence of Suzuki cross coupling reaction, electrophilic borylation and nuleophilic substitution reactions. All of the target BN-[4]helicenes were characterized by ¹H NMR, ¹³C NMR and ¹¹B NMR. One of the BN-[4]helicene was also unmbigiously confired by X-ray crystal analysis, which showed the typical helically twisted geometries. Futhermore, the BC4N ring in the BN[4]helicene exhibited weak aromaticites, wihch were quantitified by experimental and theorectical calculations. Furthermore, both of the two series of BN[4]helicene showed significant redshift of their absorption spectra and slightly blueshift emission spectra comparing to the all-carbon [4]helicene analogue. Also, good fluorescence quantum yields range from 0.42 to 0.70 were obtained for the two series of BN[4]helicenes.
Key words: arenes/aromatics, boron/nitrogen heterocycle, helicene, boron


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