Catalytic insights into acid/base conjugates: Highly selective bifunctional catalysts for the ring-opening polymerization of lactide

Herein, we report the use of acid/base complexes for the ring opening polymerization of (L)-lactide. The salt formed from an equimolar reaction of benzoic acid and DBU produced a catalyst capable of controlled polymerizations allowing for targeted molecular weights and narrow polydispersities. The use of computational analysis suggests a bifunctional catalytic mechanism wherein both the monomer and propagating hydroxyl group are activated toward polymerization. © 2011 Royal Society of Chemistry.