摘要：

We examined ring-opening polymerizations (ROPs) of ε-caprolactone in toluene at 25−60 °C catalyzed by scandium perfluoroalkanesulfonates and perfluoroalkanesulfonimides. Using these scandium catalysts, which have strong electron-withdrawing ligands, the ROPs proceeded quickly. Under identical conditions, polymerizations were completed more rapidly for reactions catalyzed by scandium trifluoromethanesulfonimide [Sc(NTf2)3] and scandium nonafluorobutanesulfonimide [Sc(NNf2)3] than for those catalyzed by scandium trifluoromethanesulfonate [Sc(OTf)3]. It was possible to synthesize poly(ε-caprolactone)s (Mn = 2.6 × 103−9.8 × 103) with low polydispersities (Mw/Mn = 1.12−1.40). After polymerization, the catalysts were easily recovered by simple filtration or by extraction with H2O and could be reused. Other rare-earth nonafluorobutanesulfonimides [M(NNf2)3; M = Tm, Sm, and Nd] were also tested. Samarium nonafluorobutanesulfonimide [Sm(NNf2)3], as well as Sc(NNf2)3, catalyzed living polymerizations of ε-caprolact...

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