Chen Ying, Lin Chaojun, Luo Zhixing, Yin Zhibo, Shi Haonan, Zhu Yanpeng, Wang Jiaobing
School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, China.
Angew Chem Int Ed Engl. 2021 Mar 29;60(14):7796-7801. doi: 10.1002/anie.202014621. Epub 2021 Feb 26.
This work reports the first double π-extended undecabenzo[7]helicene 1, which is a large chiral nanographene, composed of 65 fused rings and 186 conjugated carbon atoms. The molecular identity of 1 has been confirmed by single crystal X-ray diffraction. A wine coloured solution of 1 in dichloromethane absorbs light from ultraviolet to the near infrared, featuring an extremely large molar absorption coefficient of 844 000 M cm at 573 nm. Optically pure 1 shows a record high electronic circular dichroism intensity in the visible spectral range (|Δϵ|=1375 M cm at 430 nm) known for any discrete polycyclic aromatic hydrocarbon. These unusual photophysical properties of 1 contrast sharply with those of a mono-undecabenzo[7]helicene derivative 2.
本研究报道了首个双π-扩展的十一苯并[7]螺旋烯1，它是一种大型手性纳米石墨烯，由65个稠环和186个共轭碳原子组成。1的分子结构已通过单晶X射线衍射得以确认。1在二氯甲烷中的酒红色溶液吸收从紫外到近红外的光，在573 nm处具有844000 M⁻¹ cm⁻¹的极大摩尔吸收系数。光学纯的1在可见光谱范围内显示出创纪录的高电子圆二色性强度（在430 nm处|Δε| = 1375 M⁻¹ cm⁻¹），这在任何离散的多环芳烃中都是已知的。1的这些异常光物理性质与单十一苯并[7]螺旋烯衍生物2的性质形成鲜明对比。
