Anionic lanthanide complexes supported by a pyrrole-based tetradentate Schiff base ligand: Synthesis, structures and catalytic activity toward the polymerization of ε-caprolactone

► The synthesis of the anionic organolanthanide complexes was reported. ► Eight complexes were prepared and characterized. ► The polymerization of ε-caprolactone initiated by 1·THF was investigated.