Helical Bilayer Nonbenzenoid Nanographene Bearing a [10]Helicene with Two Embedded Heptagons

作者：Lin Yang, Yang‐Yang Ju, Miguel A. Medel, Yubin Fu, Hartmut Komber, Evgenia Dmitrieva, Jinjiang Zhang, Sebastian Obermann, Araceli G. Campaña, Ji Ma, Xinliang Feng · 发表于：Angewandte Chemie International Edition · 年份：2022 · DOI：10.1002/anie.202216193 · 被引用次数：68 · 研究领域：Synthesis and Properties of Aromatic Compounds、Luminescence and Fluorescent Materials、Graphene research and applications

The precision synthesis of helical bilayer nanographenes (NGs) with new topology is of substantial interest because of their exotic physicochemical properties. However, helical bilayer NGs bearing non-hexagonal rings remain synthetically challenging. Here we present the efficient synthesis of the first helical bilayer nonbenzenoid nanographene (HBNG1) from a tailor-made azulene-embedded precursor, which contains a novel [10]helicene backbone with two embedded heptagons. Single-crystal X-ray analysis reveals its highly twisted bilayer geometry with a record small interlayer distance of 3.2 Å among the reported helical bilayer NGs. Notably, the close interlayer distance between the two layers offers intramolecular through-space conjugation as revealed by in situ spectroelectrochemistry studies together with DFT simulations. Furthermore, the chiroptical properties of the P/M enantiomers of HBNG1 are also evaluated by circular dichroism and circularly polarized luminescence.