BIAN‐Fe(η6‐C6H6): Synthesis, Characterization, and L‐lactide Polymerization

ABSTRACTThe α‐diimine‐ligated Fe‐complex, BIAN‐Fe(C6H6), was synthesized and evaluated for the polymerization of l‐lactide. Characterization of BIAN‐Fe(C6H6) reveals that it is redox non‐innocent and suggests that it is an Fe(I) species bearing a radical‐anionic ligand. We will demonstrate that BIAN‐Fe(C6H6) is active for the ring‐opening polymerization of l‐lactide, and that polymer is produced with, or without, the use of an added external initiator. Interestingly, very high molecular weight polymers are produced in the absence of external initiator whereas polymer molecular weights that agree with theoretical calculations are produced in the presence of external initiator. To the best of our knowledge, BIAN‐Fe(C6H6) is the first Fe‐based α‐diimine catalyst reported to be active for the polymerization of l‐lactide. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2824–2830