Mechanistic Insight into Anion‐Binding Catalytic Living Cationic Polymerization

Abstract

AbstractExploiting non‐covalent interactions to catalyze challenging ionic polymerizations is an ambitious goal but is in its infancy. We recently demonstrated non‐covalent anion‐binding catalysis as an effective methodology to enable living cationic polymerization (LCP) of vinyl ethers in an environmentally benign manner. Here, we further elucidate the structure‐reactivity relationships of the elaborately designed seleno‐cyclodiphosph(V)azanes catalysts and the roles of anion‐binding interactions by a combined theoretical DFT study and experimental study. The investigation suggests that the distinct cis‐cyclodiphosph(V)azane framework combined with “selenium effect” and electron‐withdrawing 3,5‐(CF3)2‐Phenyl substitution pattern in catalyst enables a critical contribution to accessing excellent stability, anion affinity and solubility under polymerization conditions. Thus, the catalyst could leverage anion‐binding interactions to precisely control reversible and transient dormant‐active species equilibrium, allowing it to dynamically bind, recognize and pre‐organize propagating ionic species and monomer, thereby facilitating efficient chain propagation and minimizing irreversible chain transfer events under mild conditions. The more in‐depth understanding of the mechanism for anion‐binding catalytic LCP reported herein should help to guide future catalyst design and to extend this concept to broader polymerization systems where ionic species serve as crucial intermediates.