Stereospecific Polymerization of Bulky Methacrylates Using Organocatalyst in Strong Donating Solvent via Self-Controlled Mechanism

Stereospecific polymerization is an important approach to advanced synthetic polymers, and a well-designed catalyst is typically necessary for achieving high stereocontrol. In this article, we report the simple use of solvent to control the tacticity in N-heterocyclic olefin-initiated polymerization of bulky methacrylates. Upon employment of a strong donating solvent (e.g., DMF), a series of highly isotactic polymethacrylates containing bulky substituents, with mm values up to 98.2%, can be readily prepared, and high stereocontrol is maintained over a wide temperature range (25-90 degrees C). The combination of experimental and computational studies reveals that the formation of free ion pair active species in DMF is the key to isospecific polymerization, thus constructing the self-control mode. Taking advantage of the good leaving property of a bulky substituent, a versatile platform for synthesizing isotactic polymethacrylates with various small pendent ester groups, generally inaccessible by conventional polymerization catalysis due to inherent syndiotactic tendency, has been established via efficient postfunctionalization.

Automated summary

This article demonstrates the use of solvent to control the tacticity in polymerization reactions, leading to the synthesis of highly isotactic polymethacrylates with bulky substituents. The study shows that the formation of free ion pair active species in DMF is crucial for achieving stereospecific polymerization. This finding allows the establishment of a versatile platform for synthesizing isotactic polymethacrylates with various small pendent ester groups.