Ito Suguru, Fukuhara Kiyotaka, Arakawa Nayuta, Suzuki Seika, Imai Yoshitane
Department of Chemistry and Life Science, Graduate School of Engineering Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
Chemistry. 2025 Jun 18:e202501677. doi: 10.1002/chem.202501677.
The arrangement of molecules plays a crucial role in governing the luminescent properties of organic crystals. While quasiracemic crystallization, based on the co-crystallization of two structurally similar but nonidentical enantiomeric molecules, offers a promising strategy for organizing distinct species within a single crystal, its potential for tuning luminescent behavior remains largely unexplored. Herein, we have prepared quasiracemic crystals from a pair of enantiomeric binaphthyl derivatives functionalized with either ethynylnaphthalene or ethynylbenzothiadiazole groups. The molecular arrangement of the quasiracemic crystal is analogous to that of the racemic ethynylnaphthalene derivative, whereas the quasiracemic crystals exhibit mechanochromic luminescence (MCL) behavior similar to that of the racemic ethynylbenzothiadiazole derivative. Notably, the quasiracemic crystals exhibit circularly polarized luminescence (CPL), and the CPL sign is inverted relative to that of the enantiopure crystal of the ethynylbenzothiadiazole derivative. These results highlight quasiracemic crystallization as a new strategy for modulating MCL and CPL properties.
分子排列在决定有机晶体的发光特性方面起着至关重要的作用。虽然基于两个结构相似但不相同的对映体分子共结晶的准外消旋结晶为在单晶中组织不同物种提供了一种有前景的策略，但其调节发光行为的潜力在很大程度上仍未被探索。在此，我们从一对用乙炔基萘或乙炔基苯并噻二唑基团功能化的对映体联萘衍生物制备了准外消旋晶体。准外消旋晶体的分子排列类似于外消旋乙炔基萘衍生物的排列，而准外消旋晶体表现出与外消旋乙炔基苯并噻二唑衍生物相似的机械变色发光（MCL）行为。值得注意的是，准外消旋晶体表现出圆偏振发光（CPL），并且CPL信号相对于乙炔基苯并噻二唑衍生物的对映纯晶体的CPL信号是反转的。这些结果突出了准外消旋结晶作为调节MCL和CPL性质的一种新策略。
