Well-defined, solvent-free cationic barium complexes: Synthetic strategies and catalytic activity in the ring-opening polymerization of lactide

► Well-defined, solvent-free cationic barium complexes are available in high yields. ► Their solid-state structures have been elucidated. ► They can be stabilized by internal Ba···F−C secondary interactions. ► In combination with an alcohol, they promote the controlled, immortal ROP of lactide.