Tanaka Yuki, Fukui Norihito, Shinokubo Hiroshi
Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan.
Nat Commun. 2020 Aug 3;11(1):3873. doi: 10.1038/s41467-020-17684-6.
Carbon and hydrogen are fundamental components of organic molecules and a fascinating plethora of functions can be generated using these two elements. Yet, realizing attractive electronic structures only by using carbon and hydrogen remains challenging. Herein, we report the synthesis and properties of the C fragment as-indaceno[3,2,1,8,7,6-ghijklm]terrylene, which exhibits near-infrared (NIR) absorption (up to ca. 1300 nm), even though this molecule consists of only 34 carbon and 14 hydrogen atoms. A remarkably small highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap is confirmed by electrochemical measurement and theoretical calculations. Furthermore, as-indacenoterrylene is stable despite the absence of peripheral substituents, which contrasts with the cases of other NIR-absorbing hydrocarbons such as diradicaloids and antiaromatic molecules. The results of this study thus offer fundamental insights into the design of hydrocarbons with a small band gap.
碳和氢是有机分子的基本组成部分，仅利用这两种元素就能产生大量迷人的功能。然而，仅通过碳和氢来实现吸引人的电子结构仍然具有挑战性。在此，我们报告了C片段即茚并[3,2,1,8,7,6-ghijklm]并四苯的合成及性质，该分子即使仅由34个碳原子和14个氢原子组成，仍表现出近红外（NIR）吸收（高达约1300 nm）。通过电化学测量和理论计算证实了其最高占据分子轨道-最低未占据分子轨道（HOMO-LUMO）间隙非常小。此外，茚并并四苯在没有外围取代基的情况下仍很稳定，这与其他近红外吸收烃如双自由基类和反芳香分子的情况形成对比。因此，本研究结果为设计具有小带隙的烃类提供了基本见解。
