Dynamic H-Bonding Mediates Stimuli-Responsive Chiral Induction in Porous Aromatic Cages with Multicolor Chiral Afterglow.

The origin of biological chirality remains a fundamental scientific mystery. Developing artificial systems with on-off responsive chiral induction and transfer, and elucidating their mechanisms, is of paramount importance. Here, we report the first pair of chiral porous organic cage (R/S-BA-PAC) exhibiting unprecedented chiral afterglow in a film state, boosting a remarkable lifetime of 1.2 s and a dissymmetry factor (glum) of 0.001. Loading rhodamine B (RB) guest molecules enables multicolor afterglow ranging from green to red, achieving 88% energy transfer. Notably, the confined RB displays a pronounced mirror-imaged circular dichroism signal, and the induced chirality of RB demonstrates completely reversible on-off switching under water vapor/thermal stimulation, which is extremely rare in covalent porous materials. Experimental and theoretical studies have shown that the distortion of the benzoic acid moiety in RB is caused by hydrogen-bonding interactions between benzoic acid group and the BA-PAC. This distortion disrupts the electric-magnetic dipole moment orthogonality of RB, inducing its chirality. Furthermore, the reversible disruption and reconstruction of the host-guest hydrogen-bonding network induced by external stimuli is a key mechanism for dynamic chiral transfer. This study bridges chiral induction and stimuli response in porous cages, providing a versatile biomimetic platform for investigating molecular-level dynamic chirality transfer.