Metal–Organic Layers Efficiently Catalyze Photoinduced Polymerization under Visible Light

A photosensitizing metal–organic layer (MOL), IrBPY-MOL, based on hafnium–oxo clusters and cyclometalated iridium-complex-derived organic linkers, was synthesized and used as an efficient catalyst for photopolymerization of methyl methacrylate and other monomers to afford polymers with high-number-averaged molar masses and low polydispersity indices. The corresponding metal–organic framework (MOF) failed to photopolymerize or exhibited low catalytic efficiency under identical conditions. This work highlights the advantages of MOLs over their MOF counterparts in overcoming pore-size and diffusion limitations in photopolymerization reactions.