Homoleptic and Heteroleptic Substituted Amidomethylpyridine Iron Complexes: Synthesis, Structure and Polymerization of rac ‐Lactide

The synthesis of iron complexes bearing amidomethylpyridine ligands, one homoleptic [2‐[(2,6‐iPr 2 ‐C 6 H 3 )NC(Me)]C 5 H 4 N] 2 Fe ( 1 ) complex and two heteroleptic silylamide iron complexes [2‐[(2,6‐iPr 2 ‐C 6 H 3 )NC(Me)]‐6‐R‐C 5 H 4 N]Fe(N(SiMe 3 ) 2 )C 5 H 5 N (R=H, 2 Py and R=Me, 3 Py ), are described together with their application as catalysts for the Ring‐Opening Polymerization (ROP) of rac ‐lactide ( rac ‐LA). The determination of the crystal structure of the three iron complexes is reported as well as their behavior in solution by means of 1 H NMR studies. All of these complexes have shown to be active for the polymerization of rac ‐LA at 50 °C in toluene, producing, among others, high molecular weight polylactides (PLA) according to SEC analysis, along with a portion of low molecular weight cyclic polymer ( c PLA) on the basis of MALDI spectra.