Sustainable Polymerization of Natural Lactones via Iron Catalysis: An Integrated Experimental and Computational Study

An earth-abundant Fe(II)-based catalyst was employed
for efficient
and sustainable ring-opening polymerization of naturally occurring
ε- and δ-lactones. High turnover frequencies (TOFs) and
excellent control over the polymerization of δ-substituted δ-lactones
demonstrate the catalyst’s ability to process monomers traditionally
considered challenging or poorly polymerizable. Density Functional
Theory (DFT) calculations suggest the formation of dinuclear iron
species and underscore the mechanistic complexity of the system, including
a monomer-dependent variation in the rate-determining step.