Iron-Based Metal-Organic Frameworks (MOF) as Photocatalysts for Radical and Cationic Polymerizations under Near UV and Visible LEDs (385-405 nm)

Photoinitiating systems consisting of a highly porous iron(III)-based metal-organic framework (MOF), an iodonium salt, and N-vinylcarbazole are developed to initiate the free radical promoted cationic polymerization of epoxides under air and the free radical polymerization of acrylates in laminate upon exposure to near UV (385 nm) or visible (405 nm) light-emitting diodes. These systems present a satisfactory initiating ability. Among the five tested iron carboxylate MOFs exhibiting different compositions and topologies, the flexible microporous iron(III) terephthalate MIL53 is particularly interesting, leading to a final conversion of 58% for the ring-opening polymerization of epoxides. This provides the possibility of designing MOF/polymer composite materials with enhanced mechanical properties through the in situ incorporation of the MOF structure during the photopolymerization process.