Fast Ring-Opening Polymerization of 1,2-Disubstituted Epoxides Initiated by a CoIII-Salen Complex

Polyethers are an important class of polymers that find numerous applications. Ring-opening polymerization of various 1,2-disubstituted epoxides initiating a commercial, and well-defined Co-III-Salen complex is investigated in this paper. Remarkable reactivity (0.01% Co-III loadings, TOF up to 19200 h(-1)) is discovered in this transformation. High molecular weight polymers (up to 80 kg mol(-1)) are produced. In particular, polyether from ring-opening polymerization of 1,4-dihydronaphthalene oxide exhibits a glass transition temperatures (T-g) of up to 108 degrees C. By investigating the relationship between polymerization reactivity and counter ion in the Co-III complex, as well as the properties of the resultant polyethers, a cationic mechanism through an oxonium species is proposed.