Abstract
AbstractA detailed mechanistic study of ring‐opening polymerization (ROP) of l‐lactide by a lanthanum aryloxide complex, La(OTMP)3 (−OTMP = 2,4,6‐trimethylphenolate), is carried out using DFT theoretical calculations. Both initiation and propagation steps were considered. The calculations reveal the two‐step coordination‐insertion mechanism, proceeding via an unprecedented lanthanum π‐arene intermediate, with the selective acyl‐oxygen bond scission of the monomer. The first step of phenolate insertion into the La − O bond of the initiator is rate‐limiting, and the bulkiness of the aryloxide ligand initiates the ROP slowly with the activation energy of 19.3 kcal mol−1, in consistent with the activation energy (15 kcal mol−1) obtained with previous kinetic experiment. Furthermore, a rationale for the broadening of molecular weight distribution reported in this initiating system is also provided.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.