π‐Conjugated Surface Modification and Supramolecular Assembly of a Homochiral Zirconium‐Embonate Cage for Tunable Optical Properties

Comprehensive Summary The unique combination of solution processability, modular synthesis, and post‐synthetic modification (PSM) capabilities renders metal–organic cages (MOCs) a highly promising platform for diverse applications. In this work, a pair of pure enantiomers, PTC‐377(Λ,S) and PTC‐377(Δ,R) , were synthesized via selective coordination of π‐conjugated chiral cations, [Ag 2 (1 S ,2 S ‐DPEN)(DPPM)] 2+ and [Ag 2 (1 R ,2 R ‐DPEN)(DPPM)] 2+ , to the vertices of racemic ΔΔΔΔ‐ and ΛΛΛΛ‐Zr 4 L 6 (L = embonate) cage precursors, respectively. The chiral resolution and surface modification of the zirconium cage result in a pronounced circularly polarized luminescence (CPL) response. Furthermore, the loading of π‐conjugated 1,10‐phenanthroline (phen) within the mesoporous channels of PTC‐377 yields the composite phen@PTC‐377 . Thin films of this composite exhibit a dramatically enhanced optical limiting effect, with the normalized transmittance minimized at 0.11—a significant improvement over both the pristine Zr 4 L 6 cage (~1) and the parent PTC‐377 (~0.65). According to theoretical calculations, the enhanced optical limiting effect originates from the strong π–π stacking at the edge site between phen and the PTC‐377 framework, these interactions extend the conjugated system and facilitate efficient charge transfer, thereby enhancing the polarizability and hyperpolarizability of the molecule.