Multibridged azapyrenophanes were synthesized as organic circularly polarized luminescence (CPL) emitters. The glum reached +0.12 and the BCPL amounted to 2,600 M-1 cm-1 at -95 °C. The xylylene-bridging to the binaphthyl-bridged pyrenophane produced a quadruply bridged structure that prompted the pyrene excimer to adopt a D2-symmetric rigid conformation. This strategy maximized the latent CPL performance. Furthermore, these emitters functioned as temperature- and acid/base-triggered (+)/(-)- or on/off-CPL switches in which enantiospecific responses toward chiral solvents were also observed.
Takaishi et al. (2026) studied this question.