Calculation of Stereoselectivity and Alternating Probability for Chiral Cyclic Esters Polymerization
The stereostructure and monomer/unit sequence structure of chiral monomer homopolymers and copolymers are important parameters of the regularity of polymer.Improving the stereoselectivity of polymerization reactions and increasing the alternating level of two different chiral monomer copolymerization reactions are important means to obtain high regularity polymers.In order to demonstrate the performances of a new catalytic synthesis system,it is necessary to analyze the microstructure of the polymer through its nuclear magnetic resonance spectrum,and then derive the stereoselectivity and alternating level of the polymerization reaction.In recent years,there have been many publications on stereoselective polymerization and alternating polymerization of chiral cyclic ester monomers.However,there are few relevant literature,especially Chinese literature,on calculation methods.This article provides a systematic review of the identification of different chiral configurations in racemic chiral monomer homopolymers,and further demonstrates the stereoselectivity calculation methods based on two stereoselective mechanisms:chain end control mechanism and site control mechanism,as well as the alternating probability calculation method for polymers obtained from alternating polymerization reactions of different chiral monomers.
StereostructureSequence structureMultiadsStereoselectivityAlternating probability