Photocatalysis Meets Confinement: An Emerging Opportunity for Photoinduced Organic Transformations

Abstract The self‐assembled metal‐organic cages (MOCs) have been evolved as a paradigm of enzyme‐mimic catalysts since they are able to synergize multifunctionalities inherent in metal and organic components and constitute microenvironments characteristic of enzymatic spatial confinement and versatile host–guest interactions, thus facilitating unconventional organic transformations via unique driving‐forces such as weak noncovalent binding and electron/energy transfer. Recently, MOC‐based photoreactors emerged as a burgeoning platform of supramolecular photocatalysis, displaying anomalous reactivities and selectivities distinct from bulk solution. This perspective recaps two decades journey of the photoinduced radical reactions by using photoactive metal‐organic cages (PMOCs) as artificial reactors, outlining how the cage‐confined photocatalysis was evolved from stoichiometric photoreactions to photocatalytic turnover, from high‐energy UV‐irradiation to sustainable visible‐light photoactivation, and from simple radical reactions to multi‐level chemo‐ and stereoselectivities. We will focus on PMOCs that merge structural and functional biomimicry into a single‐cage to behave as multi‐role photoreactors, emphasizing their potentials in tackling current challenges in organic transformations through single‐electron transfer (SET) or energy transfer (EnT) pathways in a simple, green while feasible manner.