ma6b01099_si_001.pdf (1.1 MB)
Highly Cis/Trans-Stereoselective (ONSO)CrCl-Catalyzed Ring-Opening Copolymerization of Norbornene Anhydrides and Epoxides
journal contribution
posted on 2016-08-26, 19:03 authored by Bing Han, Li Zhang, Min Yang, Binyuan Liu, Xiaofang Dong, Patrick TheatoA (ONSO)CrCl complex-based binary
catalyst for efficient ring-opening
copolymerization (ROCOP) of epoxide and norbornene anhydride (NA)
in a stereoselective manner to afford polymers with variable stereoisomerism
is reported. The role of (ONSO)CrCl complex on the cis/trans selectivity of resulting polyester as well
as enhancement of the reaction rate has been revealed. The formation
of chelates between the endo-diester unit of the
polyester chain and the metal center plays a determinate role in the
stereoselectivity of the cis-(endo, endo)-polyester in solution copolymerization of endo-NA with epoxides in the presence of metal complex.
Additionally, the stereostructure of resulting polyester is also dependent
on the polymerization method, NA type, and the bulkiness of the substituent
of the formed ester units in the polyester chain. Accordingly, a proposed
mechanistic pathway for the stereostructure formation of polyesters
is provided.