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Complexes of lanthanide trisborohydrides, formally Ln(BH4)3(THF)n (Ln=La, Ce, Sm, Yb), were synthesized and their catalytic activity for polymerization of ε-caprolactone was studied. All the complexes can catalyze this polymerization. It was found that the catalytic activities decreased in the order of La>Ce>Sm>Yb. The crystal structure of cerium trisborohydride was determined for the first time by single crystal X-ray diffraction analysis. It is an ionic pair complex of [Ce(BH4)2(THF)5][Ce(BH4)4(THF)2]. The cationic part involves two η3-BH4 ligands, while the anionic part involves two η3-BH4 groups and two η2-BH4 groups.
Complexes of lanthanide trisborohydrides, formally Ln (BH4) 3 (THF) n (Ln = La, Ce, Sm, Yb) were synthesized and their catalytic activity for polymerization of ε-caprolactone was studied. It was found that the catalytic activities decreased in the order of La> Ce> Sm> Yb. The crystal structure of cerium trisborohydride was determined for the first time by single crystal X-ray diffraction analysis. It is an ionic pair complex of [Ce (BH4) 2 (THF) 5] [Ce (BH4) 4 (THF) 2] The cationic moiety contains two η3-BH4 ligands while the anionic moiety contains two η3-BH4 groups and two η2-BH4 groups.