Triple [5]Helicene in Naphthalenediimide Twistands with Panchromatic Chiroptical Characteristics

We report the design and synthesis of naphthalenediimide (NDI)-based triple [5]helicene twistands that enable symmetry-controlled stereodynamics and chiroptical properties. Fusion of three core-NDIs creates two conformational diastereomeric architectures, T1 and T2, with distinct configurational stability. Diastereomer T2 undergoes slow racemization at room temperature. In contrast, counterpart diastereomer T1 remains stable due to a significantly higher inversion barrier. The twistands feature a strong visible-region chiroptical response with a large molar circular dichroism of ∼70 L mol –1 cm –1 . Moreover, the twistands undergo a stepwise, reversible six-electron reduction process, highlighting efficient electronic communication across the fused framework.