Wang Jinghao, Shen Chengshuo, Zhang Guoli, Gan Fuwei, Ding Yongle, Qiu Huibin
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
Angew Chem Int Ed Engl. 2022 Feb 7;61(7):e202115979. doi: 10.1002/anie.202115979. Epub 2021 Dec 20.
Synthetic innovation for constructing sophisticated nanographenes is of fundamental significance for a variety of advanced applications. Herein, we report a distinctive method to prepare π-extended chiral nanographenes with 29 benzenoid rings and two helical breaches from a highly crowded perylene-cored oligoarylene precursor. Under Scholl's conditions, the reaction predominantly involves the regioselective and sequential cyclization in the peri- and bay regions of the perylene core, and the complanation of the 1-phenyl[5]helicene intermediate module via 1,2-phenyl migration. The resulting chiral nanographenes are configurationally stable at 180 °C due to the high diastereomerization barriers of ca. 45 kcal mol . These molecules also possess globally delocalized π-systems with low HOMO/LUMO gaps, leading to nearly panchromatic absorption, intensive electronic circular dichroism signals and deep-red circularly polarized luminescence.
合成复杂的纳米石墨烯对于各种先进应用具有至关重要的意义。在此，我们报告了一种独特的方法，可从高度拥挤的苝核低聚亚芳基前体中制备具有29个苯环和两个螺旋缺口的π-扩展手性纳米石墨烯。在肖尔条件下，反应主要涉及苝核周边和湾区的区域选择性和顺序环化，以及通过1,2-苯基迁移使1-苯基[5]螺旋烯中间体模块共面。由于约45千卡·摩尔的高非对映异构化能垒，所得手性纳米石墨烯在180°C时构型稳定。这些分子还具有全局离域的π-体系，HOMO/LUMO能隙较低，导致近乎全色吸收、强烈的电子圆二色信号和深红色圆偏振发光。
