Iron(III) Salalen Complexes for the Polymerisation of Lactide

Herein, we report the preparation and characterisation of iron(III) salalen complexes, with variation of ligand substituents and backbone investigated. Six new complexes were prepared and characterised by elemental analysis, mass spectrometry and X‐ray crystallography. These complexes have been applied for the ring opening polymerisation (ROP) of rac ‐lactide in propylene oxide. Fe( 1 )Cl was found to have a moderate isotactic preference ( P m = 0.75–0.80) and demonstrated good molecular weight control in solution (Đ = 1.02–1.18). Fe( 2–7 )Cl were also active for ROP and activities could be related to ligand structure.