Controlled cationic polymerization using RAFT agents with selenonium cations as metal-free Lewis acids: from homogeneous to heterogeneous catalysis

Abstract

Living cationic polymerization is a well-known technique, but is generally limited by strict operating conditions. Here, a series of selenonium cations was used as a new class of catalysts in this polymerization. When combined with a cationic reversible addition–fragmentation chain transfer agent, these bench-stable catalysts showed excellent ability to catalyze controlled cationic polymerization under ambient conditions, i.e., without purification of the reagents, under a non-inert atmosphere and at room temperature. Poly(vinyl ether)s with controlled molecular weights and narrow molecular weight distributions were obtained. Good chain end fidelity was demonstrated by a successful chain extension experiment. Furthermore the mechanism study showed that side reactions with water occurred in the presence of water. Moreover, heterogeneous catalysis of the polymerization was realized by loading the catalyst on polystyrene microspheres, which can be further recycled and reused.