Liu Yujia, Yuan Liuzhong, Fan Zengming, Yang Jingyuan, Wang Yue, Dou Chuandong
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 P. R. China
Chem Sci. 2024 Jul 8;15(32):12819-12826. doi: 10.1039/d4sc03124e. eCollection 2024 Aug 14.
Helicenes, featuring unique helical structures, have a long history as three-dimensional polycyclic aromatic hydrocarbons (PAHs). Incorporation of heteroatoms into helicenes may alter their electronic structures and achieve unexpected physical properties. Here, we disclose fusion of boron-doped π-systems onto helicenes as an efficient strategy to design boron-doped carbohelicenes. Two boron-doped double [6]carbohelicenes were synthesized, which possess the CB and CB polycyclic π-skeletons containing two [6]helicene subunits, respectively. The CB molecule thus represents the largest-size helicene-based boron-doped PAH. A thorough investigation reveals that the helicene moieties and boron atoms endow the polycyclic π-systems with delocalized electronic structures, and well-tunable ground-state and excited-state photophysical properties. It is notable that the CB molecule displays excited-state stimulated emission behavior and amplified spontaneous emission (ASE) properties in not only the blend films with various doped concentrations but also the pure film. To our knowledge, it is the first example of ASE-active []helicene ( ≥ 6), and moreover, such robust ASE performance has rarely been observed in PAHs, demonstrating the promising utility of boron-doped carbohelicenes for laser materials.
螺旋烯作为三维多环芳烃（PAHs）有着悠久的历史，其具有独特的螺旋结构。将杂原子引入螺旋烯中可能会改变其电子结构并获得意想不到的物理性质。在此，我们揭示了将硼掺杂的π体系融合到螺旋烯上作为设计硼掺杂碳螺旋烯的有效策略。合成了两种硼掺杂的双[6]碳螺旋烯，它们分别拥有包含两个[6]螺旋烯亚基的CB和CB多环π骨架。因此，CB分子代表了基于螺旋烯的最大尺寸的硼掺杂PAH。深入研究表明，螺旋烯部分和硼原子赋予了多环π体系离域电子结构以及可良好调节的基态和激发态光物理性质。值得注意的是，CB分子不仅在具有不同掺杂浓度的共混薄膜中，而且在纯薄膜中都表现出激发态受激发射行为和放大自发发射（ASE）性质。据我们所知，这是具有ASE活性的[]螺旋烯（≥6）的首个实例，此外，这种强大的ASE性能在PAHs中很少被观察到，这证明了硼掺杂碳螺旋烯在激光材料方面具有广阔的应用前景。
