Cage-Type Porous Organic Salts as Ship-in-a-Bottle Nanoreactors for Light-Transparent and Reusable Molecular...

Heterogenizing molecular photocatalysts while preserving their intact, pre-designed structures-without redesigning the host-remains a fundamental challenge. Immobilization within porous materials offers control over reaction environments and improved recyclability; however, most host systems require catalyst-specific structural redesign, limiting generality. We introduce a cage-type porous organic salt (POS) as a modular host platform for homogeneous, molecularly defined photocatalysts (organic molecules and metal coordination complexes) based on a ship-in-a-bottle strategy. A sodalite-type POS constructed from adamantane-based sulfonic acid and tri(ethynylphenyl)methylamine provides well-defined, light-transparent, cage-like internal cavities. Single-crystal X-ray diffraction reveals that the POS accommodates diverse photocatalysts, including anthraquinone, phenanthrenequinone, and phthalocyanine, through a unified recrystallization protocol. The framework exhibits negligible absorption in the visible region, enabling selective excitation of photocatalysts without competitive light absorption. Post-synthetic thiol-yne crosslinking of ethynyl groups on the pore surface reinforces the framework and renders it insoluble while preserving cage-like cavities. For example, a phenanthrenequinone-encapsulated POS functions as a reusable heterogeneous photocatalyst for visible-light-driven hydrogen peroxide production from isopropanol and oxygen, achieving rates of up to 4.2 mmol g^-1 h^-1 without catalyst leaching. Overall, cage-type POSs serve as light-transparent nanoreactors for intact molecular photocatalysts, providing a modular, expandable platform for photocatalyst immobilization and post-synthetic functionalization.