Multistate Circularly Polarized Luminescence Switching through Stimuli-Induced Co-Conformation Regulations of Pyrene-Functionalized Topologically Chiral [2]Catenane

Aiming at the construction of novel circularly polarized luminescence (CPL) switches with multiple switchable emission states and high dissymmetry factors (g(lum)), topologically chiral [2]catenanes were employed as the key platform to construct a novel multistate CPL switching system. Taking advantage of the precise co-conformation regulations of the resultant pyrene-functionalized [2]catenanes under different external stimuli, reversible transformations between three emission states with different CPL performances, i.e. the initial "closed" form with a |g(lum)| value of 0.012, the "open" form with an almost complete turn-off of CPL emission, and the "protonated" form with a boosted |g(lum)| value of 0.022, were successfully realized. This study demonstrates the successful construction of not only the first topological chirality-based CPL switch, but also a novel bidirectional CPL switch, thus providing a promising platform for the construction of novel chiral materials.