Fully Fused Hydrazine-Embedded Nanographene with Near-Infrared Chiroptical Emission

Embedding hydrazine into graphenic networks, where two graphitic nitrogen atoms are directly linked by an N-N bond, endows unique redox activity and antiaromatic character, yet the construction of such fully fused architectures has remained a synthetic challenge. Here we report the first fully fused hydrazine-embedded nanographene (1) synthesized via a dehydrocyclization strategy. Single-crystal X-ray diffraction revealed a hydrazine moiety embedded within a fused polycyclic carbon framework measuring 1.4 nm diagonally with a helical saddle-shape. This π-extended architecture displays near-infrared (NIR) absorption (830 nm) and emission (879 nm, Φ_F = 6.5%), as well as multistep redox processes accompanied by oxidation-induced planarization and an antiaromatic-to-aromatic transition. Chiral resolution further uncovered circularly polarized luminescence extending beyond 850 nm, which is observed for the first time from a helical nanographene. This study demonstrates that hydrazine embedment can be exploited to construct atomically precise nanocarbons with distinctive redox and NIR optical functions.