Photomodulated Supramolecular Chirality in Achiral Photoresponsive Rodlike Compounds Nanosegregated from the Helical Nanofilaments of Achiral Bent-Core Molecules

We prepared a nonchiral mixture of achiral bent-core molecules and photoresponsive rodlike liquid crystalline (LC) molecules. With the help of the isothermal photochemical nematic (N)-isotropic (Iso) phase transition of the photoresponsive rodlike LC molecules, the corresponding phase transition from a dark conglomerate BX phase to another distinguishable dark conglomerate B4 phase took place in the mixture. A large circular dichroism (CD) signal originating from supramolecular chirality was detected in the initial BX phase. On the other hand, the detected CD signal was decreased in the B4 phase after UV irradiation. Interestingly, the decreased CD signal could be reverted to the initial CD signal with visible irradiation. This chiroptical process revealed in this work was stable and reversible and thus opens up the possibility of practical applications such as rewritable optical storage.