Synthesis and molecular structure of the cationic samarium phenoxide complex [(ArO)2Sm(DME)2][BPh4]•THF and its catalytic activity for the polymerization of ε-caprolactone

The first cationic samarium phenoxide complex, [(ArO)(2)Sm(DME)(2)][BPh4] center dot THF (ArO = 2,6-di-tert-butyl-4-metyl-phenoxide) (1), has been synthesized by one-electron oxidation reaction of (ArO)(2)Sm(THF)(3) with AgBPh4 in high yield and structurally characterized. The complex I can be used as a single-component catalyst for the ring-opening polymerization of e-caprolactone (epsilon-CL) with high activity. The activity of the complex I is much higher than that of the parent neutral complex (ArO)(3)Sm(THF)(2), and is comparable to that of the divalent complex (ArO)(2)Sm(THF)(3). A coordination-insertion polymerization mechanism was supposed according to the end-group analysis. (c) 2006 Elsevier B.V. All rights reserved.