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

Abstract

ABSTRACT 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.