Synthesis of Bioctacene‐Incorporated Nanographene with Near‐Infrared Chiroptical Properties
Xiushang Xu, Rafael Muñoz‐Mármol, Serhii Vasylevskyi, Andrea Villa, Giulia Folpini, Francesco Scotognella, Giuseppe M. Paternò, Akimitsu Narita
Abstract
Abstract 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 −1 , 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 abs 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.