Photocontrolled RAFT Polymerization Mediated by a Supramolecular Catalyst

A photocontrolled reversible addition fragmentation chain transfer (RAFT) polymerization mediated by a supramolecular photoredox catalyst is reported. Cucurbit[7]uril (CB[7]) was used to form a host guest complex with Zn(II) meso-tetra(4-naphthalylmethylpyridyl) porphyrin (ZnTPOR) to prevent aggregation of ZnTPOR, which in combination with a chain transfer agent (CTA) initiated efficient and controlled RAFT polymerization in water under visible light. RAFT polymerization was significantly affected by the subtle interplay of host guest, electrostatic, and steric interactions among CB[7], ZnTPOR, and CTA. Polymerization rate was remarkably improved using CB[7]@ZnTPOR in comparison with that using ZnTPOR. The use of supramolecular interactions to modulate photocontrolled RAFT polymerization provides new opportunities to manipulate controlled radical polymerizations.