Han Yi, Xue Zibo, Li Guangwu, Gu Yanwei, Ni Yong, Dong Shaoqiang, Chi Chunyan
Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
Angew Chem Int Ed Engl. 2020 Jun 2;59(23):9026-9031. doi: 10.1002/anie.201915327. Epub 2020 Apr 7.
Incorporation of a non-hexagonal ring into a nanographene framework can lead to new electronic properties. During the attempted synthesis of naphthalene-bridged double [6]helicene and heptagon-containing nanographene by the Scholl reaction, an unexpected azulene-embedded nanographene and its triflyloxylated product were obtained, as confirmed by X-ray crystallographic analysis and 2D NMR spectroscopy. A 5/7/7/5 ring-fused substructure containing two formal azulene units is formed, but only one of them shows an azulene-like electronic structure. The formation of this unique structure is explained by arenium ion mediated 1,2-phenyl migration and a naphthalene to azulene rearrangement reaction according to an in-silico study. This report represents the first experimental example of the thermodynamically unfavorable naphthalene to azulene rearrangement and may lead to new azulene-based molecular materials.
将非六边形环并入纳米石墨烯框架可导致新的电子特性。在通过肖尔反应尝试合成萘桥连双[6]螺旋烯和含七元环的纳米石墨烯的过程中，通过X射线晶体学分析和二维核磁共振光谱证实，得到了一种意外的嵌入薁的纳米石墨烯及其三氟甲磺酸氧基化产物。形成了一个包含两个形式上的薁单元的5/7/7/5环稠合子结构，但其中只有一个显示出薁样的电子结构。根据计算机模拟研究，这种独特结构的形成是由芳鎓离子介导的1,2-苯基迁移和萘到薁的重排反应所解释的。本报告代表了热力学上不利的萘到薁重排的第一个实验实例，并可能导致新型基于薁的分子材料。
