Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen (China).
Angew Chem Int Ed Engl. 2015 Mar 2;54(10):2927-31. doi: 10.1002/anie.201409932. Epub 2015 Jan 22.
The chemical nature of the edge periphery essentially determines the physical properties of graphene. As a molecular-level model system, large polycyclic aromatic hydrocarbons, that is, so-called nanographenes, can be chemically modified through either edge functionalization or doping with heteroatoms. Although the synthetic methods for edge substitution are well-developed, incorporation with heteroatoms by the bay annulation of large PAHs remains an enormous challenge. In this study, we present a feasible peripheral sulfur annulation of hexa-peri-hexabenzocoronene (HBC) by thiolation of perchlorinated HBC. The tri-sulfur-annulated HBC and di-sulfur-annulated HBC decorated with phenylthio groups were obtained and characterized by X-ray diffraction, revealing their distinct sulfur-annulated peripheral structure. Associated with theoretical calculations, we propose that the regioselective sulfur annulation results from the minimization of strain in the aromatic backbone. We further demonstrate the structure-correlated property modulation by sulfur annulation, manifested by a decrease in band gap and tunable redox activity.
边缘外围的化学性质从本质上决定了石墨烯的物理性质。作为一个分子级别的模型系统，大的多环芳烃，即所谓的纳米石墨烯，可以通过边缘功能化或杂原子掺杂来进行化学修饰。尽管边缘取代的合成方法已经很成熟，但通过大的 PAHs 的 bay 环化来掺入杂原子仍然是一个巨大的挑战。在本研究中，我们通过全氯代 HBC 的硫醇化，提出了一种可行的六并苯并[ c ][1,2,5]噻二唑（HBC）的外围硫环化方法。得到了三硫环化 HBC 和二硫环化 HBC，并对其进行了苯基硫基修饰，通过 X 射线衍射对其进行了表征，揭示了它们独特的硫环化外围结构。结合理论计算，我们提出了区域选择性硫环化是由于芳构化主链应变最小化的结果。我们进一步通过硫环化来证明结构相关的性质调制，表现为带隙减小和可调谐的氧化还原活性。
