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

Abstract

AbstractThe synthesis of iron complexes bearing amidomethylpyridine ligands, one homoleptic [2‐[(2,6‐iPr2‐C6H3)NC(Me)]C5H4N]2Fe (1) complex and two heteroleptic silylamide iron complexes [2‐[(2,6‐iPr2‐C6H3)NC(Me)]‐6‐R‐C5H4N]Fe(N(SiMe3)2)C5H5N (R=H, 2Py and R=Me, 3Py), 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 1H 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 (cPLA) on the basis of MALDI spectra.