Aromaticity of the triplet states of corannulene and coronene
Aromaticity of the triplet states of corannulene and coronene
复制标题
晕烯和晕烯三重态的芳香性
DOI：
10.1002/poc.4464
复制
发表时间：
2022
影响因子：
1.8
通讯作者：
Gudmundsdottir, Anna D.
中科院分区：
文献类型：
--
作者：
Govorov, Dmitrii;Pitawela, Niroodha R.;Gudmundsdottir, Anna D.
阳光驱动的光化学反应是可持续有机合成的重要工具。然而，与结构对性质和反应性的影响已经确定的基态相比，对激发态的理解是有限的。特别是，提高对激发态芳构性和反芳构性的理解对于开发合成多环芳香族化合物的战略性光化学方法是必要的。本文利用密度泛函理论（DFT）优化的结构，比较了冠烯和冠烯的基本单重态（S0）和最低三重态（T1）。键长分析表明，三态冠烯和三态冠烯与苯有部分相似之处。通过核无关化学位移(NICS（0)， NICS(1.7)ZZ， NICS扫描）和感应电流密度（ACID）的各向异性计算来比较这些分子中的感应磁电流。该分析表明，每个分子在s0态具有较弱的π共轭性和部分抗芳香性。相比之下，在每个分子的t1状态中发现了圆形感应电流和明显的抗芳香性的组合。然而，环烯的t1表现出更高的稳定性，这应该有利于功能化。因此，角烯被认为更适合光化学应用。
Sunlight‐driven photochemical reactions are an important tool for sustainable organic synthesis. However, compared with ground states, for which the effects of structure on properties and reactivity are well established, the understanding of excited states is limited. In particular, an improved understanding of aromaticity and antiaromaticity in excited states is necessary to develop strategic photochemical methods for synthesizing polycyclic aromatic compounds. Herein, using density functional theory (DFT)‐optimized structures, the ground singlet (S0) and lowest triplet (T1) states of coronene and corannulene were compared. Bond length analysis demonstrated that both triplet corannulene and triplet coronene bear a partial resemblance to benzene. Nucleus‐independent chemical shift (NICS(0), NICS(1.7)ZZ, NICS scans) and anisotropy of the induced current density (ACID) calculations were carried out to compare the induced magnetic currents in these molecules. This analysis demonstrated rather weak π‐conjugation and partial antiaromaticity in the S0state of each molecule. In contrast, a combination of circular induced currents and pronounced antiaromaticity was found in the T1state of each molecule. However, the T1of corannulene exhibited higher stability, which should facilitate functionalization. Consequently, corannulene is considered more suitable for photochemical applications.