Anion-binding catalysis enables living cationic polymerization

Anion-binding interactions in nature have enabled the development of organocatalytic transformations; however, even though ionic species act as intermediates or precursors in many polymerizations, these interactions are underappreciated in polymerization catalysis. Here we introduce a powerful anion-binding catalytic strategy for cationic polymerization. In our approach, selenocyclodiphosph(V)azanes were designed as bench-stable hydrogen-bond donors to reversibly activate dormant covalent bonds (C–X, X=Cl, carboxylate and phosphate), in turn to precisely control the equilibrium between dormant covalent precursors and active cationic species under mild conditions. Experimental and computational analysis of this catalytic system revealed the key role of non-covalent anion-binding interactions between the catalyst and substrates. The living and controlled nature of this strategy, coupled with its capability for recycling catalysts and addressing certain fundamental constraints, such as metal residue and rigorous reaction conditions, delivers a versatile and robust living cationic polymerization methodology for precision polymer synthesis.