Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan.
Physics Department, Politecnico di Milano, Piazza L. da Vinci 32, 20133, Milano, Italy.
Angew Chem Int Ed Engl. 2023 Mar 27;62(14):e202218350. doi: 10.1002/anie.202218350. Epub 2023 Feb 20.
We report the synthesis of a hexabenzoperihexacene (HBPH) with two incorporated octacene substructures, which was unambiguously characterized by single-crystal X-ray analysis. The theoretical isomerization barrier of the (P,P)-/(P,M)-forms was estimated to be 38.4 kcal mol , and resolution was achieved by chiral HPLC. Notably, the enantiomers exhibited opposite circular dichroism responses up to the near-infrared (NIR) region (830 nm) with a high g value of 0.017 at 616 nm. Moreover, HBPH demonstrated NIR emission with a maximum at 798 nm and an absolute PLQY of 41 %. The excited-state photophysical properties of HBPH were investigated by ultrafast transient absorption spectroscopy, revealing an intriguing feature that was attributed to the rotational and/or conformational dynamics of HBPH after excitation. These results provide new insight into the design of chiral nanographene with NIR optical properties for potential chiroptical applications.
我们报告了一种具有两个并入的八并苯亚结构的六苯并对六苯并[def,pqr]蒄（HBPH）的合成，其通过单晶 X 射线分析得到了明确的表征。（P，P）/（P，M）构象的理论异构化势垒估计为 38.4 kcal/mol，并通过手性 HPLC 实现了拆分。值得注意的是，对映异构体在近红外（NIR）区域（830nm）表现出相反的圆二色性响应，在 616nm 处的 g 值高达 0.017。此外，HBPH 表现出 NIR 发射，最大发射波长为 798nm，绝对光致发光量子产率为 41%。通过超快瞬态吸收光谱研究了 HBPH 的激发态光物理性质，揭示了一个有趣的特征，这归因于激发后 HBPH 的旋转和/或构象动力学。这些结果为设计具有 NIR 光学性质的手性纳米石墨烯提供了新的见解，有望在手性应用中得到应用。
